physical and chemical soil properties of ten virginia

Physical and Chemical Soil Properties of Ten Virginia Department of Transportation (VDOT) Mitigation Wetlands

Gabriela Isabel Fajardo

Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE In

Crop and Soil Environmental Sciences

W. Lee Daniels, Chairman W. Michael Aust John Galbraith

James Perry G. Richard Whittecar

January 30, 2006 Blacksburg, Virginia

Keywords: Organic Amendment, Bulk Density, Hydric Soils, Redox Features

Physical and Chemical Soil Properties of Ten Virginia Department of

Transportation (VDOT) Mitigation Wetlands

Gabriela Isabel Fajardo

(ABSTRACT) In 1998, the Virginia Department of Transportation (VDOT) adopted standards for soil handling and amendments to improve created non-tidal wetland soil conditions. This study was conducted in sites where these new reconstruction practices were supposedly being implemented. Specific objectives were (i) to determine the relative effects of soil reconstruction practices on mitigation site soils, (ii) to assess the degree to which hydric soil indicators were present, and (iii) to evaluate the relative edaphic potential of mitigation site soils. Soil physical, chemical and morphological properties were analyzed in ten mitigation wetlands located in Virginia’s Piedmont and Coastal Plain. Surface soil pH was high due to liming, although some sites demonstrated low subsoil pH, indicating the presence of sulfidic materials. Nutrient levels varied, while C:N ratios were low (<25:1), suggesting a high quality organic matter complex. Organic amendments were generally applied at a rate of 4% soil organic matter content. Actual measured carbon content was <2.6% (<50 Mg ha-1). Sites not receiving organic materials and associated tillage had root-limiting bulk densities at the surface, while the majority of sites had root-limiting subsoil (30 cm) bulk densities due to weakly developed soil structure and a lack of deep ripping practices. Many sites also contained high sand content (>50%), which may negatively affect other soil properties. Nine sites had confirmed Hydric Soil Indicators, with their occurrence in a site as high as 70%. Soil reconstruction methods need to incorporate higher organic amendment rates and/or routine disking/ripping practices to improve mitigation wetland soil conditions.

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TABLE OF CONTENTS 1. INTRODUCTION..................................................................................................................... 1 2. LITERATURE REVIEW ........................................................................................................ 2

2.1 Introduction......................................................................................................................... 2 2.2 Functions and Values.......................................................................................................... 2 2.3 The U.S. Clean Water Act .................................................................................................. 3 2.4 Wetland Criteria ................................................................................................................. 3 2.5 Hydric Soils Criteria........................................................................................................... 4 2.6 Hydric Soil Indicators ........................................................................................................ 4 2.7 Wetland Mitigation ............................................................................................................. 9 2.8 Soil Properties of Mitigation Wetlands........................................................................... 10 2.9 Summary............................................................................................................................ 12

3. MATERIALS AND METHODS ........................................................................................... 13

3.1 Site Descriptions................................................................................................................ 14 3.1.1 Butcher Creek .............................................................................................................. 14 3.1.2 Charles City ................................................................................................................. 17 3.1.3 Dick Cross.................................................................................................................... 21 3.1.4 Manassas...................................................................................................................... 24 3.1.5 Mattaponi ..................................................................................................................... 29 3.1.6 Mount Stirling .............................................................................................................. 32 3.1.7 Reedy Creek ................................................................................................................. 36 3.1.8 Sandy Bottom ............................................................................................................... 43 3.1.9 Stony Creek .................................................................................................................. 46 3.1.10 SW Suffolk/Lake Kilby................................................................................................ 48

3.2 Field Sampling................................................................................................................... 51 3.3 Laboratory Methods ......................................................................................................... 53 3.4 Statistical Analysis ............................................................................................................ 53

4. RESULTS AND DISCUSSION ............................................................................................. 55

4.1 Wetland Summary ............................................................................................................ 55 4.1.1 Butcher Creek .............................................................................................................. 55 4.1.2 Charles City ................................................................................................................. 57 4.1.3 Dick Cross.................................................................................................................... 57 4.1.4 Manassas...................................................................................................................... 58 4.1.5 Mattaponi ..................................................................................................................... 58 4.1.6 Mount Stirling .............................................................................................................. 59 4.1.7 Reedy Creek ................................................................................................................. 59 4.1.8 Sandy Bottom ............................................................................................................... 60 4.1.9 Stony Creek .................................................................................................................. 61 4.1.10 SW Suffolk .................................................................................................................. 61 4.1.11 Summary of Hydric Soil Occurrence ......................................................................... 62

4.2 Soil Chemical Properties .................................................................................................. 62 4.2.1 pH................................................................................................................................. 62

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4.2.2 Acid Extractable Nutrients........................................................................................... 65 4.2.3 Soil Carbon Content .................................................................................................... 67 4.2.4 Total Nitrogen .............................................................................................................. 70 4.2.5 Carbon to Nitrogen (C:N) Ratio .................................................................................. 72 4.2.6 Mass Carbon ................................................................................................................ 74

4.3 Soil Physical Properties .................................................................................................... 76 4.3.1 Texture ......................................................................................................................... 76 4.3.2. Bulk Density ................................................................................................................ 79

4.4 Summary............................................................................................................................ 80 5. CONCLUSIONS ..................................................................................................................... 82 REFERENCES............................................................................................................................ 84 APPENDICES ............................................................................................................................. 91 VITA........................................................................................................................................... 134

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LIST OF FIGURES Figure 1. Land Resource Region (LRR) designations for Virginia. ............................................... 7 Figure 2. Location of VDOT sites sampled in this study. ............................................................ 14 Figure 3. Butcher Creek site map. ................................................................................................ 15 Figure 4. Southern view of BCK. ................................................................................................. 16 Figure 5. Charles City site map..................................................................................................... 18 Figure 6a. Southwest view of CCW. ............................................................................................ 19 Figure 6b. Northern view of CCW. .............................................................................................. 19 Figure 7. Dick Cross site map....................................................................................................... 22 Figure 8a. Northern view of DC. .................................................................................................. 23 Figure 8b. Southern view of DC................................................................................................... 23 Figure 9. Manassas site map. ........................................................................................................ 25 Figure 10a. Eastern view of MAN................................................................................................ 26 Figure 10b. Southern view of MAN. ............................................................................................ 26 Figure 11. Mattaponi site map. ..................................................................................................... 30 Figure 12a. Western view of MATTA.......................................................................................... 31 Figure 12b. Eastern view of MATTA........................................................................................... 31 Figure 13. Mount Stirling site map. .............................................................................................. 33 Figure 14a. Northern view of MTS............................................................................................... 34 Figure 14b. Southeastern view of MTS ........................................................................................ 34 Figure 15a. Reedy Creek site map – Section A. ........................................................................... 37 Figure 15b. Reedy Creek site map – Section B. ........................................................................... 38 Figure 15c. Reedy Creek site map – Section C. ........................................................................... 39 Figure 16a. Northern view of Section B at RCK. ......................................................................... 40 Figure 16b. Southern view of Section C at RCK.......................................................................... 40 Figure 17. Sandy Bottom site map................................................................................................ 44 Figure 18a. Northeastern view of SB............................................................................................ 45 Figure 18b. Southeastern view of SB ........................................................................................... 45 Figure 19. Stony Creek site map................................................................................................... 47 Figure 20. Southern view of SCW................................................................................................ 48 Figure 21. SW Suffolk site map.................................................................................................... 49 Figure 22a. Northern view of SWS............................................................................................... 50 Figure 22b. Eastern view of SWS................................................................................................. 50 Figure 23a. Average surface bulk density across sites ................................................................. 56 Figure 23b. Average subsoil bulk density across sites ................................................................. 56 Figure 24a. Average pH at 0-15 cm across sites........................................................................... 63 Figure 24b. Average pH at 30-45 cm across sites ........................................................................ 64 Figure 24c. Average pH at 90-105 cm across sites....................................................................... 64 Figure 25a. Average %C at 0-15 cm across sites.......................................................................... 67 Figure 25b. Average %C at 30-45 cm across sites ....................................................................... 68 Figure 25c. Average %C at 90-105 cm across sites...................................................................... 68 Figure 26a. Average %N at 0-15 cm across sites ......................................................................... 71 Figure 26b. Average %N at 30-45 cm across sites ....................................................................... 71 Figure 26c. Average %N at 90-105 cm across sites ..................................................................... 72 Figure 27a. Average C:N at 0-15 cm across sites......................................................................... 73

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Figure 27b. Average C:N at 30-45 cm across sites....................................................................... 73 Figure 27c. Average C:N at 90-105 cm across sites..................................................................... 74 Figure 28a. Average mass C at 0-15 cm across sites.................................................................... 75 Figure 28b. Average mass C at 30-45 cm across sites.................................................................. 75 Figure 28c. Average mass C at 90-105 cm across sites................................................................ 76

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LIST OF TABLES Table 1. Hydric Soil Indicators found in Virginia . .................................................................... 7 Table 2. Hydric Soil Indicators in Virginia grouped by Land Resource Region........................ 9 Table 3. Ten selected VDOT sites. ........................................................................................... 13 Table 4a. Typical pedon description for Chewacla soils mapped at BCK and DC.................... 16 Table 4b. Typical pedon description for Congaree soils mapped at BCK and DC. ................... 17 Table 5a. Typical pedon description for Chickahominy soils mapped at CCW......................... 20 Table 5b. Typical pedon description for Newflat soils mapped at CCW. .................................. 20 Table 6a. Typical pedon description for Aden soils mapped at MAN. ...................................... 27 Table 6b. Typical pedon description for Bermudian soils mapped at MAN. ............................. 27 Table 6c. Typical pedon description for Dulles soils mapped at MAN. .................................... 28 Table 7. Typical pedon description for Altavista soils mapped at MATTA............................. 32 Table 8a. Typical pedon description for Augusta soils mapped at MTS.................................... 35 Table 8b. Typical pedon description for Tomotley soils mapped at MTS. ................................ 35 Table 9a. Typical pedon description for Forestdale soils mapped at RCK. ............................... 41 Table 9b. Typical pedon description for Lenoir soils mapped at RCK. ..................................... 41 Table 9c. Typical pedon description for Molena soils mapped at RCK..................................... 41 Table 9d. Typical pedon description for Dogue soils mapped at RCK. ..................................... 42 Table 9e. Typical pedon description for Pamunkey soils mapped at RCK. ............................... 42 Table 10. Typical pedon description for Suffolk soils mapped at SWS. .................................... 51 Table 11. Representative pedon at BCK..................................................................................... 55 Table 12. Representative pedon at SB. ....................................................................................... 60 Table 13. Hydric Soil Indicator occurrence in 10 young VDOT wetlands................................. 62 Table 14. Comparison of acid-extractable nutrients across sites. ............................................... 66 Table 15. Comparison of %C in mitigation site soils to pre-existing soil conditions................. 70 Table 16. Soil texture by depth across sites. ............................................................................... 78 Table 17. Summary of site soil reconstruction methods and an estimate of soil quality............ 80

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ACKNOWLEDGEMENTS

I would like to express my sincere gratitude to my advisor and committee chair, Dr. W. Lee Daniels for his support and guidance throughout this project. His vast knowledge and expertise in soils has motivated me to do my best, and for that, I am forever grateful. I would also like to extend my thanks to my committee: Dr. Jim Perry and Dr. Rich Whittecar for their support and assistance in this project, Dr. W. Michael Aust, who first exposed me to wetland science, and Dr. John Galbraith for his endless encouragement. Special thanks to the Virginia Transportation Research Council for funding this study, and allowing me to pursue my interest in wetland science. I would like to especially thank Mike Fitch and Mike Perfater of the TRC in Charlottesville. The VDOT Environmental Division and their district personnel provided access and essential background information on all sites which I am thankful for. Steve Russell, Leo Snead and Ricky Woody with the Environmental Division were particularly helpful.

In addition, I would like to offer my sincere thanks and appreciation to Steve Nagle, Megan Carter, and Molly Rogerro for their help in the field, W.T. Price for his assistance in the lab, Sue Brown for her support, and Pat Donovan for her assistance in generating maps. I would also like to recognize Mike Schmidt for initiating this project.

I would like to thank my family and friends as well for their undying support and

encouragement. They have been a constant source of unconditional love and inspiration.

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1. INTRODUCTION Cowardin et al. (1979) define wetlands as transitional zones between upland and aquatic environments, where the presence of water at or near the soil surface supports plants adapted to such conditions. Wetlands, through their normal everyday functions, provide enumerable values to society, which include water quality (Confer & Niering, 1992; Reddy & Gale, 1994), flood storage (National Research Council, 2001; Reddy & Gale, 1994), endangered species habitat (Allen & Feddema, 1996; National Research Council, 2001), and recreational activities (Brinson and Rheinhardt, 1998). With our recent knowledge of the importance of wetlands, the U.S. Federal Government has established a policy of “no-net-loss” of wetlands via compensatory mitigation in the United States (National Research Council, 2001). Through the Clean Water Act, and similar federal and state legislation, mitigation is a mandatory process to safeguard wetlands against non-permitted human activities. Mitigation is a procedure that includes avoidance of impacts, minimization of impacts, restoration, and finally, compensation for unavoidable impacts (Brown & Lant, 1999). Predominant activities responsible for wetland loss include urban development, agricultural/forestry activities, and highway construction. In Virginia, the Department of Transportation (VDOT) has been responsible for the majority of impacts to wetlands in recent years (Atkinson et al. 1993). Many have questioned the effectiveness of mitigation due to the perceived and reported failure of created wetlands to replace original form and functions (Edwards & Proffitt, 2003; Mitsch & Wilson, 1996; Race & Fonseca, 1996; Shaffer & Ernst, 1999). Improper water levels and hydroperiod (Confer & Niering, 1992; Whittecar & Daniels, 1999; Mitsch & Wilson, 1996), as well as inadequate soil physical (Bishel-Machung et al., 1996; Cummings, 1999), chemical (Daniels & Whittecar, 2004), biogeochemical (Atkinson et al., 1993; Stolt et al., 2000) and hydrologic properties (Daniels & Whittecar, 2004) have been cited as reasons that limit ecological development and appropriate succession in created wetlands. These apparent differences between created and natural wetlands stem from lax permit compliance and enforcement (Race & Fonseca, 1996), certain design and construction methods (Daniels & Whittecar, 2004), and insufficient length of time for post-construction monitoring (Mitsch & Wilson, 1996). Hydric soils are perhaps the least understood and most difficult to establish of the three parameters used to delineate and assess wetlands (hydrology and vegetation are the other two). More research is needed to better understand hydric soil development and processes, which will presumably lead to improved site design methods and created wetland viability. Therefore, the specific objectives of this study were to: 1. Determine the relative effects of soil reconstruction practices, such as topsoiling and organic

amendments on mitigation site soils; and 2. Evaluate the degree to which hydric soil indicators are found in created wetlands; and 3. Assess the relative edaphic potential of mitigation site soils.

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2. LITERATURE REVIEW 2.1 Introduction In the past, “wetlands” were often considered a nuisance and deemed to be useful only when drained. However, since the 1970s, our knowledge and understanding of wetlands’ role in the environment has increased dramatically. A resulting reversal in attitude by scientists and politicians alike toward wetlands led to the inclusion of policies within existing federal and state regulations, such as Section 404 of the Clean Water Act (CWA). The CWA was first enacted “to maintain and restore the chemical, physical, and biological integrity of the waters of the United States”. In order for wetlands to be protected under the CWA, they must meet three criteria: wetland hydrology, wetland vegetation, and hydric soils. In addition, wetlands have to be connected to navigable waters of the United States, which include coastal and inland waters, lakes, rivers, streams, and their tributaries (Environmental Laboratory, 1987). Before jurisdictional wetlands (those that meet all three criteria) can be disturbed, impact mitigation requirements must be met (exempted disturbance activities include agriculture, silviculture, and ranching activities (Gaddis & Cubbage, 1998)). Wetland mitigation is a sequential process that involves avoidance, minimization, restoration, and then compensation for unavoidable impacts. Once it is deemed that impacts to wetlands are unavoidable, a permit must be obtained from the U.S. Corps of Engineers, and certain state and local agencies. Since this process has been in effect, the number of wetland creation projects has soared (Abbruzzese et al., 1987; Allen & Feddema, 1996). Overall, new wetland creation has proven to be a very difficult task (National Research Council, 2001). Certain important functions are not being replaced and the physical and chemical properties of created wetlands are often not comparable to natural wetlands. For the most part, created wetland soils have less microtopographic variability (Stolt et al., 2000; Whittecar & Daniels, 1999), lower organic matter contents (Atkinson et al., 1993; Bishel-Machung et al., 1996; Campbell et al., 2002; Cole et al., 2001; Cummings, 1999; Havens et al., 2002; Shaffer and Ernst, 1999; Stolt et al., 2000; Whittecar & Daniels, 1999), sandier textures (Bishel Machung et al., 1996; Campbell et al., 2002; Stolt et al., 2000), and higher bulk densities (Atkinson et al., 1993; Bishel-Machung et al., 1996; Cummings, 1999; Nair et al., 2001; Whittecar & Daniels, 1999) when compared with adjacent or local natural wetland soils. 2.2 Functions and Values Functions and values are often used synonymously with respect to description of important wetland processes, however it should be noted that only some wetland functions have value. As explained by Brinson and Rheinhardt (1998), functions are the normal or characteristic activities that take place within a wetland, whereas values are societal benefits derived from the goods and services provided by wetland functions. In essence, wetland value is assessed by an estimate of the monetary worth of various functions to society. Wetland functions include water storage, nutrient trapping, accumulation of inorganic sediments and organic matter, and maintenance of plant communities as well as vertebrate populations (Brinson & Rheinhardt, 1998; Dahl, 1990). Many of these functions are beneficial, and even manipulated by society, because these respective traits can prevent flood damage

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(National Research Council, 2001; Reddy & Gale, 1994), improve water quality (Confer & Niering, 1992; Reddy & Gale, 1994), and provide habitat for threatened and endangered species (Allen & Feddema, 1996; National Research Council, 2001) at little or no cost. For example, a 1990 study by the Environmental Protection Agency (1995) showed that without the Congaree Bottomland Hardwood Swamp in South Carolina, the area would need a $5 million wastewater treatment plant. While most wetlands perform multiple functions, it is important to note that not all wetlands provide all documented functions (National Research Council, 2001). 2.3 The U.S. Clean Water Act In general, before the 1970s, wetlands were widely considered wastelands that perpetuated disease and various pests. Due to this negative image, many wetlands were drained and filled for alternative uses, particularly agriculture, forestry, and coastal development. For example, wetlands are often associated with prime agricultural land due to their high organic matter content and nutrient availability (Reddy & Gale, 1994). As a result, the United States lost an estimated 53% of its estimated wetlands base (Dahl, 1990) to agricultural and urban uses between the late 1700s and 1990. In light of recent understanding of wetland function and the values they provide to society, Section 404 of the CWA was expanded to protect wetlands from further anthropogenic destruction. The basic provisions of the CWA are to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters”. Section 404 granted the U.S. Corps of Engineers (USCOE) permit authority for dredge and fill operations in jurisdictional wetlands (Gaddis & Cubbage, 1998). Once authority was established, the USCOE proceeded in defining the term ‘wetland’, which is as follows:

Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas (Federal Register, 1982).

2.4 Wetland Criteria A wetland is deemed to be jurisdictional when three criteria have been established: hydrophytic vegetation, wetland hydrology, and hydric soils (Environmental Laboratory, 1987). To meet the vegetation criterion, a site must be dominated (> 50%) by plants that are adapted to life in saturated soil conditions. A list of plant species can be found in the U.S. Fish and Wildlife Service’s National List of Plant Species that Occur in Wetlands (Reed, 1988), and state and federal agencies maintain updated lists for each regulatory region or district. Wetland species have an indicator status of obligate wetland (OBL), facultative wetland (FACW), or facultative (FAC), which is a measure of their affinity for wetland conditions (Environmental Laboratory, 1987). OBL species almost always occur (>99%) in wetlands, FACW species usually occur in wetlands (67%-99%), but can sometimes be found in non-wetlands, and FAC species are equally likely to occur in wetlands or non-wetlands (34%-66%). Upland species have an indicator status of facultative upland (FACU) and obligate upland (UPL). FACU species occur sometimes (1-33%) in wetlands, but occur more often in non-wetlands (67-99%), while UPL species rarely

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occur (<1%) in wetlands, but occur almost always in non-wetlands under natural conditions (>99%) (Reed, 1988). Wetland hydrology is defined by the frequency and duration of soil saturation or inundation during the growing season. According to the Corps of Engineers’ Wetlands Delineation Manual (1987), the soil must be inundated or saturated to the surface continuously for 5 to 12.5% of the growing season in most years (50% probability of recurrence). The lower threshold is used for areas that are definitely wetlands (e.g. long term ponded and very poorly drained conditions), while the longer threshold is used in marginal wetland systems (Burdt, 2003), such as poorly and somewhat poorly drained soils. The 1987 manual also defines the growing season as the portion of the year when soil temperature at 50 cm below the surface is above biological zero (5° C). In eastern Virginia, the average growing season lasts 248 days; therefore in areas that are undeniably wetlands, hydrology must be evident for 12 consecutive days, while those in marginal areas (e.g. somewhat poorly and poorly drained conditions) must demonstrate wetland hydrology for 31 consecutive days (National Research Council, 2001). Hydric soils are soils that “formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part” (Federal Register, July 13, 1994). Although this current definition has been revised over time, it still is subject to questions of interpretation. Duration of saturation, flooding, or ponding is vaguely defined (Mausbach & Parker, 2001; Vepraskas & Sprecher, 1997), but it is expected to be of sufficient time-frame for anaerobic conditions to develop and persist. Faulkner et al. (1991) found that, in Louisiana, 14 to 28 days of surface saturation were needed to promote anaerobic conditions. 2.5 Hydric Soils Criteria In addition to the hydric soils definition, a list of criteria was developed to identify hydric soil series. The criteria are as follows (Federal Register, February 24, 1995):

1. All Histosols except Folists, or 2. Soils in the Aquic suborders, great groups or subgroups, Albolls suborder, Aquisalids, Pachic subgroups, or

Cumulic subgroups that are: a. somewhat poorly drained with a water table to 0 cm from the surface during the growing season; or b. poorly drained or very poorly drained and have either:

i. a water table equal to 0 cm during the growing season if textures are coarse sand, sand, or fine sand in all layers within 50 cm, or for other soils

ii. a water table less than or equal to 15 cm from the surface during the growing season if the permeability is ≥15 cm/h or in all layers within 50 cm, or

iii. a water table at ≤30 cm from the surface during the growing season if permeability is <15 cm/h in any layer within 50 cm, or

3. Soils that are frequently ponded for long (1 wk+) duration or very long duration during the growing season, or

4. Soils that are frequently flooded for long duration or very long duration during the growing season. 2.6 Hydric Soil Indicators Generally, applying the Hydric Soils Criteria in the field is not directly practical because it requires that water table depths and permeability be estimated, both of which are time-

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consuming and expensive (Vepraskas & Sprecher, 1997). Instead, hydric soil indicators are used for on-site investigations. Field indicators are meant to complement the hydric soils definition and criteria, thus lack of hydric soil indicators does not necessarily exclude the soil from being hydric (USDA-NRCS, 2003). However, presence of confirmed hydric soil indicators is considered as proof-positive evidence in the field. Hydric soils develop via reduction-oxidation (redox) chemical reactions, which are driven by anaerobic conditions (Vepraskas, 2001) and an active microbial biomass. Water saturation slows oxygen movement in the soil, and as a result, it does not replenish quickly enough to accommodate the demands of soil flora and fauna. Once oxygen in the soil is depleted, other elements (Mn, Fe, and S) are used as terminal electron acceptors in bacterial respiration (Craft, 2001; Vepraskas, 2001). As this occurs, distinctive morphological features develop within the soil. These include accumulation of organic materials, redox related color patterns, and S odors (Vepraskas, 2001). Thus, field indicators are formed predominately by accumulation, loss, or transformation of Fe, Mn, S, or C compounds (Hurt & Carlisle, 2001; USDA-NRCS, 2003). Organic Carbon Organic carbon-based features consist of significant accumulations of organic soil material, mucky mineral soil material, and black mineral soil material (Vepraskas, 2001). Each type of material is defined by the organic carbon content within a narrowly defined soil layer. Organic soils must have at least 12% organic carbon, mucky mineral contains at least 5%, and anything below the 5% threshold is mineral soil (based on 0 percent clay). As the clay content increases, the requisite C-content thresholds increase as well (Sprecher, 2001). Organic matter accumulation occurs in soils when the rate of accumulation exceeds the rate of decomposition. This “turnover” dynamic is regulated by several factors, including i) environmental conditions such as temperature, Eh, and pH; ii) hydrologic regime and associated saturation and gas exchange; iii) C-substrate palatability, and iv) supply of available electron acceptors, such as O2, NO3

-, and SO42- (Collins & Kuehl, 2001; Craft, 2001; McLatchey & Reddy, 1998). All of these

factors determine the active microbial biomass in the soil, which in turn control the rate of decomposition (Haraguchi et al., 2002). McLatchey and Reddy (1998) concluded that organic matter turnover is strongly correlated with electron acceptor availability and redox conditions. Stolt et al. (2001) concurred that hydrologic regime played a role in organic matter accumulation. They observed that wetland sites with longer periods of saturation at or near the soil surface had higher amounts of organic carbon, presumably due to anaerobic conditions inhibiting decomposition. Manganese and Iron Related Features The oxidation and reduction of Mn and Fe generate a range of soil color patterns and solid forms that are components of a set of features termed “redoximorphic features” (Vepraskas, 1992). Because these types of features are visible and frequently occur in zones with alternating periods of reducing and oxidizing conditions, they are often used to predict where seasonal saturation occurs in soils (He et al., 2003; Stolt et al., 1998). Some redox features form under permanently saturated conditions as well (e.g. reduced matrix). The reduced forms of Fe and Mn are mobile in water, and will continue to move until they reach an oxidizing environment or are lost from the system (Soil Survey Staff, 1999; Stolt et al., 1998). There are three categories of Fe

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and Mn redoximorphic features: redox concentrations, redox depletions, and the reduced matrix (Vepraskas, 1992). Soil Survey Staff (1999) describes each category and are listed as follows:

a. Redox concentrations. – These are zones of apparent accumulation of Fe-Mn oxides, including: 1. Nodules and concretions, which are cemented bodies that can be removed from the soil intact.

Concretions are distinguished from nodules on the basis of internal organization. A concretion typically has concentric layers that are visible to the naked eye. Nodules do not have visible organized internal structure. Boundaries commonly are diffuse if formed in situ and sharp after pedoturbation. Sharp boundaries may be relict features in some soils; and

2. Masses, which are noncemented concentrations of substances within the soil matrix; and 3. Pore linings, i.e., zones of accumulation along pores that may be either coatings on pore surfaces

or impregnations from the matrix adjacent to the pores. b. Redox depletions. – These are zones of low chroma (chromas less than those in the matrix) where either

Fe-Mn oxides alone or both Fe-Mn oxides and clay have been stripped out, including: 1. Iron depletions, i.e., zones that contain low amounts of Fe and Mn oxides but have a clay content

similar to that of the adjacent matrix (often referred to as Albans or neoalbans); and 2. Clay depletions, i.e., zones that contain low amounts of Fe, Mn, and clay (often referred to as silt

coatings or skeletans). c. Reduced matrix. – This is a soil matrix that has low chroma in situ but undergoes a change in hue or

chroma within 30 minutes after the soil material has been exposed to air. Redoximorphic features form varying color patterns of gray, red, yellow, brown, and black. Gray colors are associated with reduced conditions because gray is the natural color of mineral particles when they are not coated by Fe-Mn oxides (Vepraskas & Sprecher, 1997) or organic matter. In order for distinct redox features to form, one or more of the following processes must occur: i) Fe3+ and Mn4+ in oxides or hydroxides have been reduced, ii) the solubilized Fe2+ and Mn2+ have moved to another portion of the soil, and iii) the mobile Fe2+ and Mn2+ oxidize to form an Fe or Mn mass, pore lining, or nodule. The first step above is required for a reduced matrix, the first two steps for formation of redox depletions, and all three steps are needed for redox concentrations to subsequently form (Vepraskas, 2001). Sulfur The reduction of S most often occurs in estuarine wetland soils because saline waters contain an abundance of sulfur; however, sulfate reduction can occur in freshwater systems as well, given that SO4

2- is present (frequently from organic matter decomposition). Sulfate-reducing bacteria, such as Desulfovibrio, Desulfobacter, and Desulfococcus are strict anaerobes (Widdel & Hansen, 1992), thus they require saturated, anoxic soil conditions. These anaerobes are responsible for reducing sulfate to H2S gas, which produces a “rotten egg” odor (Craft, 2001). Hydric Soil Field Indicators for Virginia Virginia is comprised of four USDA-NRCS (2003) Land Resource Regions (LRR; Figure 1): the East and Central Farming and Forest Region (N), South Atlantic and Gulf Slope Cash Crops, Forest and Livestock Region (P), Northern Atlantic Slope Diversified Farming Region (S), and Atlantic and Gulf Coast Lowland Forest and Crop Region (T).

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Figure 1. Land Resource Region (LRR) designations for Virginia: East and Central Farming and Forest Region (N), South Atlantic and Gulf Slope Cash Crops, Forest and Livestock Region (P), Northern Atlantic Slope Diversified Farming Region (S), and Atlantic and Gulf Coast Lowland Forest and Crop Region (T) (USDA-NRCS, 2003).

Approved USDA-NRCS hydric soil field indicators vary by LRRs. In all, Virginia has 29 out of the possible 53 nationally defined hydric soil indicators (Table 1). Region N has 22 field indicators, region P has 17 indicators, region S has 22, and region T has 20 hydric soil indicators (Table 2). Presence of one or more indicators is proof that the soil meets the hydric soil definition (Hurt & Carlisle, 2001). Table 1. Hydric Soil Indicators found in Virginia (USDA-NRCS, 2003). A. INDICATORS FOR ALL SOILS REGARDLESS OF TEXTURE:

A1 – Histosol. Soil that classifies as a Histosol, except Folists. A2 – Histic Epipedon. Soil that has a histic epipedon A3 – Black Histic. Soils with a layer of peat, mucky peat, or muck 20 cm (8 in.) or more thick starting within the upper 15 cm of the soil surface having hue 10YR or yellower, value 3 or less, and chroma 1 or less. A4 – Hydrogen Sulfide. Soils with a hydrogen sulfide odor within 30 cm of the soil surface. A5 – Stratified Layers. Soils with several stratified layers starting within the upper 15 cm of the soil surface. One or more of the layers has value 3 or less with chroma 1 or less and/or it is muck, mucky peat, peat, or mucky modified mineral texture. The remaining layers have value 4 or more and chroma 2 or less. A6 – Organic Bodies. Soils with a layer that has 2% or more organic bodies of muck or a mucky modified mineral texture, approximately 1 to 3 cm in diameter, starting within 15 cm of the soil surface. A7 – 5 cm Mucky Mineral. Soils with a mucky modified mineral layer 5 cm or more thick starting within 15 cm of the soil surface. A9 – 1 cm Muck. Soils with a layer of muck 1 cm or more thick with value 3 or less and chroma 1 or less starting within 15 cm of the soil surface. A10 – 2 cm Muck. Soils with a layer of muck 2 cm or more thick with value 3 or less and chroma 1 or less starting within 15 cm of the soil surface.

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Table 1. Hydric Soil Indicators found in Virginia (cont.). S. INDICATORS FOR SOILS WITH SANDY SOIL MATERIALS:

S1 – Sandy Mucky Mineral. Soils with a mucky modified mineral layer 5 cm or more thick starting within 15 cm of the soil surface. S4 – Sandy Gleyed Matrix. Soils with a gleyed matrix which occupies 60% or more of a layer starting within 15 cm of the soil surface. S5 – Sandy Redox. Soils with a layer starting within 15 cm of the soil surface that is at least 10 cm thick that has a matrix with 60% or more of its volume chroma 2 or less and 2% or more distinct or prominent redox concentrations as soft masses and/or pore linings. S6 – Stripped Matrix. Soils with a layer starting within 15 cm of the soil surface in which iron/manganese oxides and/or organic matter have been stripped from the matrix exposing the primary base color of soil materials. The stripped areas and translocated oxides and/or organic matter form a diffuse splotchy pattern of two or more colors. The stripped zones are 10% or more of the volume; they are rounded and approximately 1 to 3 cm in diameter. S7 – Dark Surface. Soils with a layer 10 cm or more thick starting within the upper 15 cm of the soil surface with a matrix value 3 or less and chroma 1 or less. At least 70% of the visible soil particles must be covered, coated, or similarly masked with organic material. The matrix color of the layer immediately below the dark layer must have chroma 2 or less. S8 – Polyvalue Below Surface. Soils with a layer that has value 3 or less and chroma 1 or less starting within 15 cm of the soil surface underlain by a layer(s) where translocated organic matter unevenly covers the soil material forming a diffuse splotchy pattern. At least 70% of the visible soil particles in the upper layer must be covered, coated, or masked with organic material. Immediately below this layer, the organic coating occupies 5% or more of the soil volume and has value 3 or less and chroma 1 or less. The remainder of the soil volume has value 4 or more and chroma 1 or less. S9 – Thin Dark Surface. Soils with a layer 5 cm or more thick within the upper 15 cm of the surface, with value 3 or less and chroma 1 or less. At least 70% of the visible soil particles in this layer must be covered, coated , or masked with organic material with value 4 or less and chroma 1 or less to a depth of 30 cm or to the spodic horizon, whichever is less.

F. INDICATORS FOR SOILS WITH LOAMY AND CLAYEY SOIL MATERIAL:

F2 – Loamy Gleyed Matrix. Soils with a gleyed matrix that occupies 60% or more of a layer starting within 30 cm of the soil surface. F3 – Depleted Matrix. Soils with a layer at least 15 cm thick with a depleted matrix that has 60% or more chroma 2 or less starting within 25 cm of the surface. The minimum thickness requirement is 5 cm (2 in.) if the depleted matrix is entirely within the upper 15 cm of the mineral soil. F4 – Depleted Below Dark Surface. Soils with a layer at least 15 cm thick with a depleted matrix that has 60% or more chroma 2 or less starting within 30 cm of the surface. The layer(s) above the depleted matrix have value 3 or less and chroma 2 or less. F5 – Thick Dark Surface. Soils with a layer at least 15 cm thick with a depleted matrix that has 60% or more chroma 2 or less (or a gleyed matrix) starting below 30 cm of the surface. The layer(s) above the depleted or gleyed matrix have hue N and value 3 or less to a depth of 30 cm and value 3 or less and chroma 1 or less in the remainder of the epipedon. F6 – Redox Dark Surface. Soils with a layer at least 10 cm thick entirely within the upper 30 cm (12 in.) of the mineral soil that has: a. matrix value 3 or less and chroma 1 or less and 2% or more distinct or prominent redox concentrations as

soft masses or pore linings, or b. matrix value 3 or less and chroma 2 or less and 5% or more distinct or prominent redox concentrations as

soft masses or pore linings. F7 – Depleted Dark Surface. Soils with redox depletions, with value 5 or more and chroma 2 or less, in a layer at least 10 cm thick entirely within the upper 30 cm of the mineral soil that has: a. matrix value 3 or less and chroma 1 or less and 10% or more redox depletions, or b. matrix value 3 or less and chroma 2 or less and 20% or more redox depletions. F8 – Redox Depressions. Soils in closed depressions subject to ponding with 5% or more distinct or pore linings in a layer 5 cm or more thick entirely within the upper 15 cm of the soil surface.

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Table 1. Hydric Soil Indicators found in Virginia (cont.).

F12 – Iron/Manganese Masses. Soils on floodplains with a layer 10 cm or more thick with 40% or more chroma 2 or less, and 2% or more distinct or prominent redox concentrations as soft iron/manganese masses with diffuse boundaries. The layer occurs entirely within 30 cm of the soil surface. Iron/manganese masses have value 3 or less and chroma 3 or less; most commonly they are black. The thickness requirement is waived if the layer is the mineral surface layer. F13 – Umbric Surface. Soils on concave positions of interstream divides and in depressions, a layer of 15 cm or more thick starting within the upper 15 cm of the soil surface with value 3 or less and chroma 1 or less immediately underlain by a layer 10 cm or more thick with chroma 2 or less.

TF. TEST INDICATORS FOR SOILS WITH LOAMY AND CLAYEY SOIL MATERIAL: TF2 – Red Parent Material. Soils formed in parent material with a hue of 7.5YR or redder that have a layer at least 10 cm thick with a matrix value 4 or more and chroma 4 or less and 2% or more redox depletions and/or redox concentrations as soft masses and/or pore linings. The layer is entirely with 30 cm of the soil surface. The minimum thickness is 5 cm if the layer is a mineral surface layer. TF4 – 2.5Y/5Y Below Dark Surface. Soils with a layer at least 15 cm thick with 60% or more hue 2.5Y or yellower, value 4 or more, and chroma 1; or hue 5Y or yellower, value 4 or more, and chroma 2 or less starting within 30 cm of the soil surface. The layer(s) above the 2.5Y/5Y layer have value 3 or less and chroma 2 or less. TF7 – Thick Dark Surface 2/1. Soils with a layer at least 15 cm thick with a depleted matrix that has 60% or more chroma 2 or less (or a gleyed matrix) starting below 30 cm of the soil surface. The layer(s) above the depleted or gleyed matrix have hue 10YR or yellower, value 2.5 or less and chroma 1 or less to a depth of 30 cm and value 3 or less and chroma 1 or less in the remainder of the epipedon. TF10 – Alluvial Depleted Matrix. Soils on frequently flooded floodplains that have a layer with a matrix that has 60% or more chroma 3 or less with 2% redox concentrations as soft iron masses, starting within 15 cm of the soil surface and extending to a depth of more than 30 cm.

Table 2. Hydric Soil Indicators in Virginia grouped by Land Resource Region: East and Central Farming and Forest Region (N), South Atlantic and Gulf Slope Cash Crops, Forest and Livestock Region (P), Northern Atlantic Slope Diversified Farming Region (S), and Atlantic and Gulf coast Lowland Forest and Crop Region (T) (USDA-NRCS, 2003). LRR Indicators N A1, A2, A3, A4, A5, A10, S1, S4, S5, S6, S7, F2, F3, F4, F5, F6, F7, F8, F12, TF2, TF7, TF10. P A1, A2, A3, A4, A5, A6, A7, A9, S4, S5, S6, S7, F2, F3, F8, F12, F13. S A1, A2, A3, A4, A5, A10, S1, S4, S5, S7, S8, S9, F2, F3, F4, F5, F6, F7, F8, TF2, TF4, T510. T A1, A2, A3, A4, A5, A6, A7, A9, S4, S5, S6, S7, S8, S9, F2, F3, F6, F8, F12, F13. 2.7 Wetland Mitigation In 1989, the Bush administration formally declared its no-net loss of wetlands goal (National Research Council, 2001). This goal is met primarily through wetland mitigation, which is used to limit impacts to wetlands via a process of avoidance, minimization, restoration, and compensation. Avoidance, as the term suggests, prevents impacts to wetlands, either by not taking a certain action or modifying parts of an action. Restoration involves rectification of an impact by the on-site repair, rehabilitation, or restoration of the actual affected environment to pre-existing conditions. Compensating for an impact requires replacement of a wetland, which usually entails creating wetlands in formerly upland or drainage modified environments (Atkinson et al., 1993; Brown & Lant, 1999). As a part of this process, wetland creation and

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restoration projects have increased dramatically over the years (Abbruzzese et al., 1987; Allen & Feddema, 1996). The increase of wetland creation projects in Virginia has been primarily a result of highway construction in the Coastal Plain (Atkinson et al. 1993), where approximately 72% of the state’s wetlands are located (Tiner & Finn, 1986). Nationally, the USCOE receives approximately 10,000 permit applications per year, of which it approves 6,500, denies 500, and sees 3,000 withdrawn (Beck, 1994). Although wetland creation has become more prevalent, the success rate of created wetlands leaves much to be desired. A controversial 1991 study in Florida reported an overall success rate of only 27% (Florida Department of Environmental Regulation, 1991). Nonetheless, many other authors concur that compensatory mitigation may not be replacing lost wetlands on either an aerial and/or a functional basis (Allen & Feddema, 1996; Brown & Lant, 1999; Brown & Veneman; Kelly, 2001; Shaffer & Ernst, 1999). However, Dahl (2000) reports that although the no-net loss goal is not being met, substantial progress has been made in reducing the rate of loss, as an 80% reduction in wetland loss was observed from the previous decade (1980s). Because the low success rate of compensatory mitigation is recognized by USCOE, mitigation requirements tend to mandate additional area beyond the actual impact size. Recommended mitigation ratios (amount mitigated: amount lost) are 1:1, 2:1, 5:1, and even higher (Allen & Feddema, 1996; Kelly, 2001). In Virginia, the ratio is commonly 1:1 for emergent wetlands, 1.5:1 for shrub-scrub, and 2:1 for forested wetlands (W.L. Daniels, personal communication). Exceptional areas may require mitigation rates at 5:1 or higher. These ratios reflect a presumed success rate, with forested wetlands being the most difficult to successfully replace. 2.8 Soil Properties of Mitigation Wetlands There are many factors that are presumed to affect soil functions in wetlands. However, as I reported earlier, many studies indicate that mitigation wetlands do not exhibit the same properties and functions as those of comparable natural wetlands. Many attribute this contrast to differing soil properties, such as lower organic matter content, higher bulk density, and coarser textures. Organic Matter Organic matter is the driving force behind many wetland functions; thus it is a frequent parameter used to assess hydric soil development (Campbell et al., 2002; Shaffer and Ernst, 1999). Organic matter supports macroinvertebrate detritivores, herbivores, and their predators (Gibson et al., 1994), improves cation exchange (Stanturf & Schoenholtz, 1998) and supplies nutrients, such as N and P (Stauffer & Brooks, 1997). Physical properties affected by organic matter include lowered bulk density and increased hydraulic conductivity, infiltration capacity, and water holding capacity (Stanturf & Schoenholtz, 1998). In addition, organic matter maintains the structural stability of a soil by reducing wind and water erosion (Stauffer & Brooks, 1997).

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In general, soil organic matter consists of approximately 56% organic carbon (Nelson and Sommers, 1982), but that ratio (C:OM) varies somewhat by soil type and other factors. It is estimated that wetlands contain an average soil organic carbon (SOC) content of 72 kg C m-2 in the contiguous United States (Kern, 1994), and it is believed that wetlands can be managed for their potential C gain and storage in the next few decades. In fact, the potential global carbon sequestration in wetlands is estimated to be 0.1-0.2 Gt C y-1 (Metting et al., 1998). It is a well established fact that the organic matter levels in created wetlands are much lower than in reference wetlands (Atkinson et al., 1993; Bishel-Machung et al., 1996; Campbell et al., 2002; Cole et al., 2001; Havens et al., 2002; Shaffer and Ernst, 1999; Stolt et al., 2000; Whittecar & Daniels, 1999). Stolt et al. (2000) reported that carbon concentrations in A horizons were five to ten times higher in reference wetlands. Atkinson et al. (1993) also interpreted that low organic matter coupled with high oxygen levels could be a self-perpetuating problem because high oxygen levels accelerate remobilization of organic matter that could otherwise accumulate in soils with appropriate anoxic conditions. A case in point is Cummings’ (1999) five year study on five paired wetlands in Virginia. She found that C levels in the mitigation sites were not increasing with time, and concluded that the degree of saturation was insufficient to promote organic matter accumulation. Although differences in organic matter in created versus natural wetlands are well understood, the lateral variability, depth distribution, and mass accumulation functions of soil carbon in wetlands are not. Many studies have measured only the surface horizon and did not extend sampling beyond 20 cm (Atkinson et al., 1993; Campbell et al., 2002; Havens et al., 2002; Shaffer & Ernst, 1999). Furthermore, many researchers report carbon content in soils solely as a concentration percentage (% C kg-1), without calculating or estimating the actual total mass of carbon (Mg C ha-1) within the soil (Atkinson et al., 1993; Bishel-Machung et al., 1996; Campbell et al., 2002; Craft et al., 1991; Shaffer & Ernst, 1999). This latter calculation requires data on both %C and bulk density within defined and sampled depths in a given pedon. Because soil carbon is a major component of organic matter, and organic matter plays a major role in hydric soil development, this property deserves more detailed estimation. Bulk Density From the onset, created wetland soils exhibit higher bulk densities than natural wetlands due to compaction of soils during construction (Campbell et al., 2002; Nair et al., 2001). These denser soil layers are sustained by low organic matter contents (Atkinson et al., 1993; Bishel-Machung et al., 1996; Nair et al., 2001) and lack of associated biotic mixing and pedoturbation. Nair et al. (2001) found a direct relationship between C content and bulk density in Florida, showing that soils with ≤2.5% total C were more compact than soils with >2.5% total C. Increased bulk densities in soils directly result in reduced porosity, gas exchange, infiltration, and hydraulic conductivity. As a consequence, increased surface water flow, erosion, and sedimentation may occur (Montgomery et al., 2001). Furthermore, and perhaps most importantly, highly compacted soils prevent vegetation establishment or lead to limited growth and depth due to an inability for roots to penetrate exceedingly firm soils. Root limiting bulk densities in soils range from 1.45 Mg m-3 for fine textures to 1.75 Mg m-3 for coarse loamy textures (Daniels & Whittecar, 2004).

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Texture In addition to low organic matter contents and high bulk densities, created wetlands tend to have differing textures (Bishel-Machung et al., 1996; Campbell et al., 2002) than reference wetlands. Surface soil textures in created wetlands often have higher sand contents due to excavation of finer-textured upper soil layers (Bishel Machung et al., 1996; Campbell et al., 2002; Stolt et al., 2000) and exposure of coarser textured C horizons. This is problematic because sand-sized particles commonly have lower cation exchange and water-holding capacities and higher permeability and porosity (Stolt et al., 2000) than finer-textured soils. However, many coarse-loamy hydric soils underlie native forested wetlands in the Virginia Coastal Plain (P.J. Thomas, personal communication), so coarse soil texture per se is not directly limiting to wetland function where soil hydrologic conditions are appropriate. Coarse textured soils in mitigation sites are also common where dredge spoil and/or sandy mining overburden wastes and tailings have been placed (W.L. Daniels, personal communication). 2.9 Summary Wetlands are diverse ecosystems that play a critical role in the environment. Jurisdictional wetlands are identified by the presence of hydrophytic vegetation, wetland hydrology, and hydric soils. Hydric soil development is controlled largely by the hydrologic regime, organic matter dynamics, and microbial population. Redoximorphic features and H2S production in hydric soils result from an active microbial population, while organic matter accumulates when its decomposition is inhibited by slowed rates of biotic turnover. Field indicators, such as redox features, are used as a direct way to examine whether hydric soils are present because they are field recognizable. However, hydric soils can exist where field indicators are not present. The number of created wetlands has increased as a result of the mitigation process, however the quality of these wetlands are still under debate. Low quantities of organic matter, high bulk densities, and unsuitable textures persist in created wetlands, which result in a reduced level of function and inappropriate vegetation types and structures. The issues of soil compaction and low organic matter in VDOT mitigation sites were originally reported to VDOT in the early and mid-1990’s by Daniels and co-workers in annual research reports and in previously cited articles. By 1998, VDOT had responded by introducing specific soil handling and amendment criteria into new permit specifications. This study was funded by VDOT in 2000 to specifically assess the quality of newly implemented soil reconstruction practices across a range of new mitigation sites.

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3. MATERIALS AND METHODS This research program was funded by the Virginia Transportation Research Council with the support of the VDOT Environmental Division. The overall goal of VDOT in funding this portion of this research project was to obtain a relative (but scientifically defensible) estimation of the quality and effectiveness of their recent (post-1998) non-tidal compensatory mitigation efforts. Therefore, our site selection was focused upon (1) recently constructed wetlands that are (2) relatively large in size, and (3) have been constructed by a variety of different methods with respect to soil reconstruction approaches. This project was also collaborative with Dr. Rich Whittecar at Old Dominion University and Dr. Jim Perry at the Virginia Institute of Marine Science (VIMS), who assessed each mitigation site for hydrologic setting and vegetation, respectively. Their detailed hydrologic/vegetation sampling locations were nested within our soil sampling locations, and they performed overall hydrologic/vegetation assessments of each site (Daniels et al., 2005). Ten sites were selected for sampling in 2002 and 2003 based upon a combination of factors including (1) input from the VDOT Environmental Division and (2) previous experience of the principal investigators and established background research histories. Thus, the ten recently constructed VDOT wetlands listed in Table 3 were assessed for combined soil/hydrologic/vegetation indicators. Figure 2 shows their general location in Virginia.

Table 3. Ten selected VDOT sites used in this study. Site Name Site

Abbreviation Initial Construction Date /Sampling

Date Size (ha)

VDOT District

Butcher Creek BCK 1999/10-2003 2.02 Richmond Charles City CCW 1998/4-2002 20.78 Richmond Dick Cross DC 2000/8-2002 10.45

Richmond

Manassas MAN 1999/7-2002 15.87

Northern Virginia

Mattaponi MATTA 2001/5-2002 8.41

Fredericksburg

Mt. Stirling MTS 1999/10-2003 13.00 Richmond

Reedy Creek RCK 2001/3-2004 18.22 Richmond Sandy Bottom SB 2002/8-2003 19.43 Hampton Roads

Stony Creek SCW 1998/7-2002 2.27 Hampton Roads SW Suffolk/Lake

Kilby SWS 2002/4-2004 5.02 Hampton Roads

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Figure 2. Location of VDOT sites sampled in this study.

3.1 Site Descriptions 3.1.1 Butcher Creek Butcher Creek (BCK; Figs. 3-4) is located north of State Route 677 within the western floodplain of Butcher Creek in Mecklenburg County, VA. It is a small (2.02 ha) constructed non-tidal riverine wetland situated entirely within the Piedmont region of Virginia, and is compensatory mitigation for impacts related to the widening of State Route 58. The geology of the site is composed of felsic volcanic rocks of the Carolina Slate Belt (Rader & Evans, 1993), and original soils mapped at the site include Chewacla (Table 4a) and Congaree (Table 4b) series. The Congaree series consists of deep, well to moderately well-drained loamy soils that formed in fluvial sediments. Chewacla soils are described as having very deep, somewhat poorly drained conditions, and formed in alluvium. The Congaree series are classified as Oxyaquic Udifluvents, while the Chewacla series are Fluvaquentic Dystrudepts. Chewacla is found on the hydric soils list, and has a seasonal high water table that is 15 – 46 cm below the surface from November to April (NTCHS, 1995). BCK is situated on a floodplain and was used previously for agricultural purposes.

BCK was designed into multiple compartments to generate different hydrologic regimes. Two basins (A & B) were created, where basin A is the northernmost, hour-glass shaped basin, with a base elevation of 93.1 m. Basin B is a triangle-shaped system that stretches east-west, and has a base elevation of 92.7 m. These two basins are separated by a central berm that has a maximum elevation of 93.9 m, and drops to 93.4 m on the eastern end of the berm to allow drainage from Basin A into Basin B. Dividing the site permitted multiple water capture, which included floodwater from Butcher Creek, groundwater, and sheetflow/precipitation.

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Figure 3. Butcher Creek site map.

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Figure 4. Field work at sample location 4 at BCK (view of southern portion).

Table 4a. Typical pedon description for Chewacla soils mapped at BCK and DC (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description

Redox Location Roots Texture Structure Comments

Ap 0-10 7.5YR 4/4 -- -- --

2VF, 2F, 2M L 1MGR few fine flakes of mica

Bw1 10-36 10YR 4/4

10YR 5/3 F2F Fe masses 2F, 2M SICL 1MSBK

common fine flakes of mica

Bw2 36-66 10YR 4/4

10YR 5/2 C2F In matrix 2F, 2M CL 1MSBK many fine flakes of mica

7.5YR 4/6 C2D Fe masses

Bw3 66-97 7.5YR 4/4

10YR 5/1 C2D In matrix 2F L 1MSBK many fine flakes of mica

Bw4 97-119 7.5YR 5/8

10YR 5/1 C2D In matrix 1F CL 1MSBK many fine flakes of mica

Bw5 119-152

7.5YR 5/8 -- -- -- 1F CL 1MSBK many fine flakes of mica

10YR 5/1

2.5YR 5/8

C 152-183

7.5YR 4/4 -- -- -- -- L 0MA many fine flakes of mica

7.5YR 5/1

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Table 4b. Typical pedon description for Congaree soils mapped at BCK and DC (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-28 7.5YR 4/4 -- -- -- 3F L 1FGR many fine flakes of mica

C1 20-46 10YR 4/3 -- -- -- 3F L 0MA many fine flakes of mica

C2 46-56 10YR 3/3 -- -- -- 3F L 0MA few fine flakes of mica

C3 56-81 10YR 3/3 -- -- -- 3F SL 0MA

many fine flakes of mica; few fine fragments of charcoal

Ab 81-97 10YR 3/2 -- -- -- 3F L 1FGR many fine flakes of mica

Bb 97-157 7.5YR 4/4 -- -- -- 1F SICL 2COPR/SBK common fine flakes of mica

C' 157-203

7.5YR 5/8 -- -- -- -- CL 0MA common fine flakes of mica

10YR 5/3

10YR 6/3

In order to achieve wetland hydrology, soil cutting and reconstruction was necessary. An average depth of 1.07 m of soil was removed, which was based on the regional groundwater table and flooding of Butcher Creek. Nine wells were monitored for six months (one growing season before construction). Before local (non-hydric) topsoil was returned, one part composted organic backfill (492 m3 ha-1) was mixed with two parts topsoil. The organic amendment originated from Scott Company, located in Lawrenceville, VA, and consisted of composted leaf matter and yard waste that had a pH of 6-8, was at least 40% organic, and had an average bulk density that did not exceed 0.74 g cm-3 per VDOT’s established criteria. This mixture was then spread over the site to a 15 cm layer. Shallow disking (5 – 8 cm) occurred before planting, and lime was added at a rate of 560 kg ha-1. Furthermore, 120 kg ha-1 of fertilizer (15-30-15) was applied to the soil, as well as a total of 70 kg of time released fertilizer (18-6-12) for the plants. No deep soil ripping occurred onsite. Three wetland planting zones were included in the design of the site to maintain a system that involves 50% forested, 12% scrub-shrub, and 38% emergent wetland. The planned forested habitat surrounds the two basins, and includes species such as green ash (See App. A for scientific names), pin oak, willow oak, American elm, and swamp white oak. Scrub-shrub species were generally located in the northwestern section of the site, and included black willow, silky dogwood, and swamp rose. Emergents were planted in the basins, and consisted of mud plantain, woolgrass, hop sedge, and seedbox. 3.1.2 Charles City Charles City (CCW; Figs. 5, 6a-b) is a large, non-tidal wetland flat located west of State Route 623 in Charles City County, VA, near the town of Mount Airy and the Chickahominy River. It serves as mitigation for impacts associated with the construction of Route 199 around Williamsburg. In order to achieve no-net loss, CCW was designed to support 88% forested, 6% scrub-shrub, and 6% emergent wetlands.

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CCW lies within the Coastal Plain physiographic province, and is underlain by the Shirley formation. The soils at CCW were mapped as Chickahominy loam (Table 5a) and Newflat (Table 5b) silt loam. The Chickahominy soils series are very deep and poorly drained. They are classified as Typic Endoaquults, and are hydric. The seasonal high water table in this series ranges from 0 – 15 cm during November to April (NTCHS, 1995). The Newflat soil series are very deep and somewhat poorly drained. They are classified as Aeric Endoaquults. Both the Chickahominy and Newflat soils form in clayey fluvial sediments on nearly level areas of Coastal Plain stream terraces. The creation of CCW was initiated in 1998/1999 and involved placing a berm across a headwater stream to Barrows Creek to periodically and differentially pond the site.

Figure 5. Charles City site map.

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Figure 6a. Southwest view of CCW near sample location 1.

Figure 6b. Northern view of CCW near sample location 4.

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Table 5a. Typical pedon description for Chickahominy soils mapped at CCW (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


A 0-5 2.5Y 4/2 -- -- --

3F, 3M, 3C SIL 2M/FGR

Eg 5-18 2.5Y 4/2

2.5Y 5/4 C1F Fe masses

3F, 3M, 3C SIL

2MGR/ 1FSBK few fine flakes of mica

10YR 3/2 C1D

Mn masses

Btg1 18-33 N 6/0 10YR 5/8 C2P Fe masses 2F, 2M SICL 3M/FSBK few fine flakes of mica

Btg2 33-84 N 6/0 10YR 5/8 C1P Fe masses 2F, 2M SIC

1MPR/ 3FABK few fine flakes of mica

Btg3 84-119 5Y 6/1 10YR 5/8 C2P Fe masses 2F, 1M SIC

2COPR/ 3MABK few fine flakes of mica

Btg4 119-155 5Y 5/1

10YR 5/8 C2P Fe masses 1F, 1M SIC 3MABK few fine flakes of mica

Btg5 155-216 5Y 6/1

10YR 5/8 C2P Fe masses 1F, 1M CL 3MABK few fine flakes of mica

Table 5b. Typical pedon description for Newflat soils mapped at CCW (Soil Survey Staff, 1994). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Oi 3-0 -- -- -- -- -- -- --

leaf litter and partially decomposed organic materials

A 0-5 10YR 3/1 -- -- -- 3F, 2M SIL 2FGR

E 5-13 10YR 6/2

10YR 6/4 F1F Fe masses 2F SIL 2FGR

10YR 5/6 F1D Fe masses

Bt 13-25 10YR 6/4

10YR 7/1 F1D In matrix 1F CL 1FSBK

10YR 6/6 M3F Fe masses

Btg1 25-51 10YR 6/2

10YR 5/6 C2D Fe masses 1F CL

2MPR/ 2FABK


Btg2 51-89 10YR 6/1

10YR 5/6 C2D Fe masses 1F CL

2MPR/ 2FABK


Btg3 89-191 10YR 6/1

7.5YR 5/6 C2D Fe masses -- SIC 2MSBK

Land excavation occurred around the perimeter of the inundated area. Ideally, the

shallow areas of the pond would provide suitable conditions for the proposed emergent and scrub-shrub wetlands, while the excavated area would offer an environment in which the proposed forested wetland could thrive. Average excavation of the upper soil profile was 0.61 – 0.91 m, which was based on soils analysis, well data, and nearby reference wetlands. Overall, forested areas have an elevation from 9.97 – 10.58 m, scrub-shrub zones have elevations ranging

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from 9.51 – 9.81 m, and emergent wetland ranges from 8.84 – 9.69 m. Because CCW is underlain by a thick argillic soil horizon, the site was designed to perch water. In reconstructing the soil profile, the existing topsoil (approx. 2.5 – 7.6 cm thick) was stockpiled and then graded, incorporating the clayey subsoil.

Also, some burn piles of pine (prior vegetation) were integrated at the location of the

burn pile and spread out. The site was then disked once prior to USCOE grade approval to a depth of 15 cm, making many passes over the site, since the topsoil/clay chunks were not breaking up easily due to the very dry conditions (drought year). Deep ripping was also done once with a chisel plow crossing twice, which ended up recompacting the ripped soil on the second pass (Peter Constanzer, personal communication). The site also received a lime application at the rate of 1.2 Mg ha-1. No fertilizer or organic amendments were used. Planting did not occur until spring 2004 because of lack of agency concurrence on hydrology. Trees planted include willow oak, pin oak, river birch, and cherrybark oak. In the scrub-shrub sections, swamp rose, buttonbush, and bald cypress were planted. Emergents included soft rush, swamp smartweed, and woolgrass. 3.1.3 Dick Cross Dick Cross (DC; Figs. 7, 8a-b) is located off Rt. 615 near South Hill, VA in Mecklenburg County, VA and is situated on the northern floodplain of the Roanoke River and the upslope edge of the floodplain. Bordering the wetland is Allen Creek, a tributary of the Roanoke River; DC is approximately 1.2 km west of where Allen Creek joins the Roanoke River, which is impounded as Lake Gaston. DC is located in the Piedmont region, and overlies late Proterozoic to Mississippian aged Buggs Island Granite (Rader & Evans, 1993). The soils at DC, like BCK, were mapped as Congaree silt loam and Chewacla silt loam (Jurney & Henry, 1956; see BCK for description). In conjunction with BCK, DC is compensation for unavoidable impacts associated with the widening of State Route 58 and construction of the State Route 1 Bridge over the Roanoke River.

DC can be described as having three distinct zones: north of the access road, south of the access road, and east of the oxbow feature. The access road was intentionally situated and designed to function as a berm, creating a zone that is capable of supporting forested wetland. Extensive excavation of this site was required because there were very few surface water inputs that could be relied on to sustain a large wetland area. In fact, north of the access road was the only zone that received significant water inputs. Thus, both groundwater and overbank flooding were expected to drive the water budget. The area south of the access road was graded and terraced to produce cells of lower elevation. The terraces designated for forested wetland range in elevations of 61.4 – 61.6 m, while those terraces created for scrub-shrub wetland are at elevations of 61.6 m. The cell elevations are at 61.4 m. The oxbow feature was graded to an elevation of 61.6 – 61.9 m to correspond with the elevation of the surrounding existing forested wetland. Likewise, east of the oxbow feature was graded to match that of the existing forested wetland and the oxbow feature. Thus, the average excavation of the upper soil profile was 0.6 – 0.9 m, and was based on well data and the adjacent natural wetland. Overall, 32 wells were monitored for approximately 10 months (11/1996 – 9/1997) prior to construction.

22

Figure 7. Dick Cross site map.

23

Figure 8a. Northern view of DC from sample location 6.

Figure 8b. Southern View of DC from sample location 10.

24

In reconstructing the soil, the local non-hydric topsoil was stockpiled prior to excavation, and then replaced to a 15 cm depth. The topsoil layer was then disked to 15 cm, and received 5.0 Mg ha-1 of lime and 0.7 Mg ha-1 of fertilizer (15-30-15). No deep ripping or organic amendments were applied to the site (Chris Frye, personal communication).

Planting was approved in August, 2003 even though the site hydrology was not approved (David Bova, personal communication). DC was designed to support 75% forested, 22% scrub-shrub, and 3% emergent wetland. Forested zones were planted with water oak, swamp white oak, willow oak, and river birch, among others. Scrub-shrub species include buttonbush, crimsoneyed rosemallow, and silky dogwood. Plants in the emergent wetlands include lizard tail, duck potato, and fringed sedge. 3.1.4 Manassas

Manassas (MAN; Figs. 9, 10a-b) is located in central Prince William County, east of the Manassas Municipal Airport, and was developed to compensate for impacts to wetlands associated with the construction of the State Route 234 Bypass. MAN lies within the Piedmont physiographic province on the floodplain of Broad Run, a tributary of the Occoquan River. Its geology consists of the Triassic Newark Supergroup, which includes interbedded sandstone, siltstone, and shale (Rader & Evans, 1993). The vast majority of the native soils at MAN were mapped as Aden silt loam (Table 6a), Bermudian silt loam (Table 6b), and Dulles silt loam (Table 6c), though an inclusion of Rowland silt loam was present as well (Elder, 1989). The site was once used for farming operations.

Aden soils are very deep, poorly drained soils that form on low stream terraces in alluvial

sediments and are classified as Aeric Ochraqualfs. Bermudian soils are very deep, well-drained soils found on floodplains that form in alluvial deposits, and are classified as Fluventic Dystrudepts. Dulles silt loams are characterized as deep, moderately well and somewhat poorly drained soils formed partly in colluvium (likely periglacial slope movements) and partly in residuum from red, Triassic and Jurassic, interbedded fine grained sandstone, siltstones and shales in the Culpeper Basin of the Northern Piedmont Plateau. They occur on broad, nearly level upland and concave lowlands, and are classified as Aquultic Hapludalfs. The Rowland soil series consist of very deep, moderately well and somewhat poorly drained soils formed in alluvial sediments weathered from red and brown shale, sandstone, and conglomerate. They are classified as Fluvaquentic Dystrudepts. Aden soils are listed as a hydric soil. The seasonal high water table for the Aden series occurs from December to March at a depth of 0 – 31 cm below the surface (NTCHS, 1995).

Two major streams enter the project area: Cannon Branch from the north and Cockrell

Branch from the east. Intermittent streams from the northeast and southeast also feed the site. MAN was constructed by positioning two berms perpendicular to Cockrell Branch so as to expand wetland acreage. The pond elevation associated with the upstream berm on Cockrell Branch was established at 50.3 m by grading back the colluvium and residuum to the east at the base of the hillslopes, and grading the northwestern area down to intercept the raised water table created by the new berm. The downstream berm on Cockrell Branch has an invert elevation of 49.7 m, supposedly inhibiting an open water habitat yet providing a sufficient water table to

25

generate wetland hydrology. This second berm took advantage of the natural topography by continuing the natural ridge into the steep bordering hillslopes.

Figure 9. Manassas site map.

26

Figure 10a. Eastern view of MAN near sample location 3.

Figure 10b. Southern view of MAN near sample location 8.

27

Table 6a. Typical pedon description for Aden soils mapped at MAN (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Oi 3-0 -- -- -- -- -- -- -- partially decomposed leaves, pine needles, and twigs

Ap 0-20 10YR 6/4

10YR 7/1 M2D

In matrix

3F, 3M, 3C SIL 2FGR 1% subrounded quartz gravel

10YR 7/3 M1D

Fe masses

Btg 20-36 10YR 7/1

10YR 6/2 M2D

In matrix

3F, 3M, 3C SICL 2FSBK 1% subrounded quartz gravel

10YR 6/6 M2D

Fe masses

Bt1 36-79 7.5YR 5/6

10YR 7/1 C2P

In matrix

7.5YR 6/2 C2P

In matrix

1F, 1M C 2MSBK 1% subrounded quartz gravel

Bt2 79-147

5YR 4/4

7.5YR 6/2 C1D

In matrix

1F, 1M SICL 1M/FSBK 1% subrounded quartz gravel

C 147-198

5YR 6/2 -- -- -- -- SIL 0MA few fine mica flakes;

5YR 5/8 1% silt stone gravels

10YR 5/8

Cr 198 2.5YR 5/6 -- -- -- -- -- -- silt stone

10YR 7/1

Table 6b. Typical pedon description for Bermudian soils mapped at MAN (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-20 5YR 3/3 -- -- -- -- SIL 1FGR Bw1 20-76 5YR 3/3 -- -- -- -- SIL 1FSBK

Bw2 76-127 2.5YR 4/4 -- -- -- -- SICL 1MSBK

C 127-165

2.5YR 4/4 -- -- -- -- S 0SGR

28

Table 6c. Typical pedon description for Dulles soils mapped at MAN (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-20 7.5YR 4/4 -- -- -- 3F SIL 2FGR

1% rounded and subrounded quartz gravel up to 5 cm

Bt1 20-38 10YR 5/6 -- -- -- 3F SICL 2MSBK


Bt2 38-56 10YR 5/6

10YR 7/2 F1P

In matrix 3F SICL 2FSBK

Bt3 56-86 10YR 5/8

10YR 6/2 C1P

In matrix 1F SIC 2FSBK


10YR 6/1 C1P

In matrix

10YR 7/2 C1P

In matrix

2Btg 86-99 10YR 6/2

10YR 6/1 M3P

In matrix 1F C 2COSBK 10% weathered red shale channers

10YR 7/1 M3P

In matrix

5B 6/1 M3P In matrix

10YR 3/4 M3P

Fe masses

2Cr 99-109 -- -- -- -- -- -- -- red partially weathered shale

R 109-150 -- -- -- -- -- -- -- shale bedrock

A gradient of soil saturation was supposedly produced from the creation of the two dams.

Close to the dams there is an open water habitat at an elevation of 50.1 m, where emergent and aquatic species can exist. Further away from the dams, the soil saturation decreases to support scrub-shrub species as well as emergents. Swale terraces were also created, and are associated with the existing drainages, Cockrell Branch, and the smaller tributaries. These terraces were constructed to support scrub-shrub species and emergents. In the floodplain area, located west of Cannon Branch, broad flats and terraces were constructed to support tree species.

Overall, the original soil was cut on an average of 0.56 m, which was based on adjacent

reference wetlands and well data. In all, there were 56 wells that were installed on the site and monitored for 7 months by VDOT, VPI, and the USGS. The site hydrology was expected to be maintained by the occurrence and movement of groundwater since the geologic formation (fractured Mesozoic sedimentary rocks) of this area could transmit appreciable amounts of locally derived groundwater through its fractures (VHB, 1997). Subgrade soils were compacted to 95% maximum compaction to limit seepage losses followed by the return of loose subsoil and topsoil. Before seeding occurred, the soil was disked to an unknown depth, though no deep ripping took place. In addition, 2.6 Mg ha-1 of fertilizer (15-30-15) and 1.4 Mg ha-1 of lime were applied to the site to increase nutrient availability. No organic amendments were used.

Wetland hydrology was approved in April 2000, and planting occurred the following month. MAN is designed to support 68% forest, 8% scrub-shrub, and 24% emergent wetland. Trees planted include green ash, pin oak, and willow oak. Scrub-shrub species include black

29

willow, tag alder, buttonbush, and swamp rose. Emergents include shallow sedge, water plantain, and duck potato.

3.1.5 Mattaponi Mattaponi (MATTA; Figs. 11, 12a-b) is a multiple impact mitigation wetland “bank” that is located southwest of Milford, VA in Caroline County, VA. It is bounded on the north by State Route 207, on the east by railroad tracks and State Route 722, and on the south and west by the Mattaponi River. The site was built to provide off-site compensation for unavoidable impacts to wetlands in the non-tidal portions of the York River watershed. MATTA is located within the Coastal Plain physiographic province near the fall line that separates the Coastal Plain from the Piedmont. Because of this, the site is in a geologic transition zone that includes the Chesapeake Group and Lower Tertiary deposits (Rader & Evans, 1993). The site sat on a terrace above the active floodplain, where agricultural activities were predominant. The majority of the soils were mapped as Altavista sandy loam (Table 7), while a small area on the southern boundary was mapped as a Bojac sandy loam. Altavista soils are very deep, moderately well drained soils on stream terraces that formed in loamy marine and fluvial sediments. They are classified as Aquic Hapludults. Bojac soils are very deep, well drained soils, and are found in stream terraces and floodplains. They form in loamy and sandy marine and fluvial sediments, and are classified as Typic Hapludults.

MATTA was created by grading the surface down to 0.61 – 1.2 m to produce microtopographical features that model the ridge and swale landscape of point bars found nearby in the Mattaponi river floodplain. The ridge terraces, with a base elevation of 25.9 m, were designed to support forested wetlands, the sloped banks (25.8 m) for scrub-shrub vegetation, and the depressional flats (25.75 m) for water-tolerant emergent species. In effect, MATTA encompasses 50% forested wetland, 25% scrub-shrub, and 25% emergent wetland.

Forested zones were designed across the site, and include American hornbeam, green ash, river birch, and willow oak. Scrub-shrub zones were designed along linear ‘fingers’ that stretch toward the northwest portion of the site. The scrub-shrub community consists of tag alder, buttonbush, and possumhaw. Emergent areas are situated throughout the sloughs, and include arrow arum, crimsoneyed rosemallow, creeping primrose-willow, and watercress. Wetland hydrology was approved in May 2003 and the site was planted to permanent vegetation during that time.

The site design grades were based on one year data from 22 groundwater monitoring wells and adjacent wetlands. The soil was reconstructed by excavating 0.3 m below final grade and then back-filled to final grade with sandy loam topsoil. Prior to replacement, the topsoil was amended to 4% organic content with composted yard waste, which consists of blended leaves, branches, and grass clippings. This compost material originated from Grind-All, a commercial handler based in Richmond, VA. The specifications for the composted yard waste included moisture content (35-55%), pH (5.5-8.0), particle size (passing a 25 mm screen), soluble salt concentration (≤ 3.0 dS/m), and nutrient contents (N: 0.5-2.5%; P: 0.2-2.0%; K: 0.3-1.5%). In addition to these requirements, the compost material also had to be free of viable weed seed and low in heavy metal content (Robert Pickett, personal communication). Before seeding occurred,

30

the soils were disked to a depth of 15 cm, and during the seeding of the site, 1.8 Mg ha-1 of lime and 240 kg ha-1 of fertilizer (15-30-15) were applied. No deep ripping occurred on-site.

Figure 11. Mattaponi site map.

31

Figure 12a. Western view of MATTA near sample location 4.

Figure 12b. View of eastern section of MATTA near sample location 8.

32

Table 7. Typical pedon description for Altavista soils mapped at MATTA (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-20 10YR 5/2 -- -- -- 3F SL 1MGR E 20-30 10YR 6/3 -- -- -- 1F SL 1FGR BE 30-38 10YR 6/6 -- -- -- 1M SCL 1FSBK Bt1 38-51 10YR 5/6 5YR 5/8 C1P Fe masses 1F CL 1MSBK few flakes of mica Bt2 51-89 10YR 5/8 10YR 6/2 C2P In matrix 1F SCL 1MSBK few flakes of mica BC 89-107 10YR 6/6 10YR 6/2 M2P In matrix -- SL 1FSBK few flakes of mica

C 107-152 10YR 5/8 -- -- -- -- SL 0MA few flakes of mica,

10YR 6/1 gravelly

3.1.6 Mount Stirling Mount Stirling (MTS; Figs. 13, 14a-b) is located adjacent to the Chickahominy River, and east of State Route 155 in Charles City County, VA. This site was created as mitigation for unavoidable impacts to wetlands in construction of the I-95 Atlee Elmont Interchange. Mount Stirling was designed to support 74% forested, 24% shrub-scrub, and 2% emergent wetlands. The hydrology of the site was adjusted in early 2001 by raising the crest elevations of three water control structures to provide greater retention of surface water and three depressional areas were excavated to increase shallow ponding. In July 2002, wetland hydrology was approved, and planting was completed in January 2003. However, due to high plant mortality, replanting of the site occurred in early 2004. MTS is located in the Coastal Plain physiographic province, and is underlain by the Shirley formation (Rader & Evans, 1993). The original soils at MTS are mapped as Augusta sandy loam (Table 8a) and Tomotley fine sandy loam (Table 8b), with inclusions of Altavista fine sandy loam, Dragston fine sandy loam, and Nawney silt loam. The Augusta series consist of very deep, somewhat poorly drained soils. They are classified as Aeric Endoaquults. The Tomotley series are very deep, poorly drained soils. These soils are Typic Endoaquults, and are listed on the hydric soil list. Tomotley soils have a seasonal high water table of 0 – 31 cm below the surface from November to April (NTCHS, 1995). Altavista soils are very deep and moderately well drained and are Aquic Hapludults; Dragston series are very deep, somewhat poorly drained, and classified as Aeric Endoaquults. Finally, Nawney soils are very deep, poorly drained soils found on floodplains. They are listed as Typic Fluvaquents and are found on the hydric soil list. The seasonal high water table is at 0 – 15 cm from January to December (NTCHS, 1995). All of these soil series formed in loamy marine and fluvial sediments. Furthermore all series except Nawney (floodplains) are located on stream terraces.

A portion of the site (approximately 80%) was prior-converted farm land (Travis Crayosky, personal communication). The site was expanded by cutting the soil to a maximum of 0.76 – 0.91 m, which was based on well data from on-site and adjacent wetlands, elevations of adjacent wetlands, and presence of hydric soils or redoximorphic features. Approximately ten

33

Figure 13. Mount Stirling site map.

34

Figure 14a. Northern view of MTS near sample location 3.

Figure 14b. Southeastern view of MTS near sample location 1.

35

Table 8a. Typical pedon description for Augusta soils mapped at MTS (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-23 10YR 4/3 -- -- -- 3F L 1FGR common fine flakes of mica

Bt 23-48 10YR 6/3

10YR 5/6 M2D

Fe masses 1F SCL 1MSBK few fine flakes of mica

10YR 6/2 C2F In matrix

Btg1 48-61 10YR 6/2

10YR 5/6 M2P

Fe masses -- CL 2MSBK common fine flakes of mica

Btg2 61-132

10YR 6/2

10YR 5/6 M2P

Fe masses -- CL 2MSBK common fine flakes of mica

Btg3 132-152 5Y 6/1

10YR 5/6 C2P

Fe masses -- SCL 1COSBK common fine flakes of mica

Cg 152-178 5Y 6/1

10YR 4/4 M2P

Fe masses -- SL 0MA

5% fine pebbles, few fine flakes of mica

Table 8b. Typical pedon description for Tomotley soils mapped at MTS (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color Redox Color

Redox Description


Ap 0-18 10YR 4/2 -- -- -- 2F, 2M SL 1MGR Btg1 18-30 10YR 7/1 10YR 5/6 F1P Fe masses 1F, 1M SL 1MSBK Btg2 30-107 2.5Y 6/2 7.5YR 5/8 C2P Fe masses -- SCL 2MSBK 10YR 5/6 C2P Fe masses

BCg 107-127 2.5Y 6/2 -- -- -- -- SL 1FSBK

10YR 6/1 10YR 5/8

Cg 127-183 10YR 6/1 10YR 5/6 M2P Fe masses -- LS 0MA

7.5YR 5/8 M2P Fe masses

wells were monitored for a period of one year before construction. The graded topsoil was stockpiled and re-spread to a depth of 15 cm, and then disked to a depth of 10 cm before seeding occurred. The surface was ripped and disked once, crossing the site numerous times until the topsoil appeared “fluffy” (Travis Crayosky, personal communication). Fertilizer (10-30-15) was added to the soil at a rate of 27 kg ha-1. No organic amendments or lime applications were made, nor did any deep ripping occur on the site.

Topographic variability has been implemented on this site by including depressional areas to increase shallow ponding. To minimize grading activities on the naturally sloping site, a series of terraces were designed, which extends in the south-north direction. The elevations set for the forested wetland areas range from 1.83 m in the lowest terrace to 2.43 m in the highest terrace. Scrub-shrub zones are at elevations of 1.68 m in the lowest terrace to 2.29 m in the highest terrace. Emergent zones are scattered across the site in small depressions that are typically 0.15 m lower in elevation than the scrub-shrub zones. In order for wetland hydrology to be reestablished, the drain tiles and ditches were removed. Water from Collins Run enters the

36

site at the upper cell (southern end), flows through a series of water control structures, and exits at the northern end into the Chickahominy River. Wetland hydrology is expected to be maintained by a groundwater system supplemented by surface water runoff and high flows of the adjacent stream.

Forested species include red maple, river birch, water oak, and black willow. Scrub-shrub plants include red chokeberry, winterberry, and highbush blueberry. 3.1.7 Reedy Creek The Reedy Creek mitigation wetland (RCK, Figs. 15a-c, 16a-b) is located adjacent to the Appomattox River, and off of State Route 602 in Chesterfield County, VA. Construction of this site was begun in May 2001 and completed in January 2002. This site is mandatory compensation for impacts to wetlands associated with construction of Route 288. Reedy Creek is composed of 18.2 ha, where 86% is forested, 2% is shrub-scrub, and 12% is designed for emergent wetland. Wetland hydrology was approved in 2003, and the site was planted in the winter of 2005. RCK is located in the Piedmont physiographic province. The geology of the site belongs to the Triassic Newark Supergroup, which includes Mesozoic sedimentary rocks – RCK overlies arkosic sandstone (Rader & Evans, 1993). Soils in Section A were mapped as Forestdale silt loam (Table 9a), Lenoir loam (Table 9b), and Molena loamy sand (Table 9c). Section B consisted of Dogue loam (Table 9d), Lenoir loam, and Pamunkey loam (Table 9e). The soils in Section C were mapped as Pamunkey loam, Dogue loam, and Forestdale silt loam. Molena soils are very deep, somewhat excessively drained, and formed in sandy alluvial deposits on stream terraces. They are classified as Psammentic Hapludults. Pamunkey series have soils that are very deep and well drained. They formed in stratified fluvial sediments derived principally from weathered igneous and metamorphic rocks on nearly level to sloping stream terraces, and are classified as Ultic Hapludalfs. Dogue soils are very deep and moderately well drained, and formed in loamy fluvial and marine sediments on stream terraces. They are categorized as Aquic Hapludults. Forestdale series consist of very deep, poorly drained soils that developed in clayey and silty alluvium on low terraces and are Typic Endoaqualfs. The Lenoir series are also composed of very deep, poorly drained soils that formed on interstream divides and uplands. They have stratified clayey sediments of marine or fluvial origin, and are classified as Aeric Paleaquults. Both the Forestdale series and Lenoir series are on the hydric soils list. For Lenoir, the seasonal high water table is located 30 – 75 cm below the surface from December to May, while the Forestdale series has a seasonal high water table at 15 – 61 cm from January to April (NTCHS, 1995).

This site was constructed by cutting the soil on an average of 0.30 – 0.46 m, with the deepest cuts occurring at 0.76 – 0.91 m. Well data from on-site and adjacent wetlands, elevations found in adjacent wetlands, and presence of hydric soils or redoximorphic features were factors in determining the soil grade. Sixteen wells and six piezometers were monitored for four months (March-June 2002) before soil cutting occurred. The graded topsoil was stockpiled and re-spread to a depth of 30 cm, and disked to a depth of 15 cm before seeding. Potassium as KCl (0-0-50) was applied to the soil at a rate of 55 kg ha-1, dolomitic limestone at 400 kg ha-1,

37

Figure 15a. Reedy Creek site map - Section A.

38

Figure 15b. Reedy Creek site map - Section B.

39

Figure 15c. Reedy Creek site map - Section C.

40

Figure 16a. Northern view of Section B at RCK near sample location 7.

Figure 16b. Southern view of Section C at RCK near sample location 6.

41

Table 9a. Typical pedon description for Forestdale soils mapped at RCK (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-15 10YR 4/2 -- -- -- 1F SICL 1FGR

Btg1 15-66 10YR 6/1

10YR 5/6 F2D

Fe masses 1F SIC 2MSBK

Btg2 66-152 10YR 6/1

10YR 5/6 C2D

Fe masses -- SICL 1MSBK

Table 9b. Typical pedon description for Lenoir soils mapped at RCK (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


A 0-8 10YR 3/1 -- -- -- 3F, 3M L 1FGR

E 8-20 10YR 4/1 -- -- -- 3F, 1M L 1FGR

Bt 20-33 10YR 6/6

10YR 6/2 F2D In matrix 1M CL 1MSBK


Btg1 33-91 10YR 5/1

10YR 6/8 M2D Fe masses 1F C

2MSBK/ ABK

Btg2 91-130 10YR 6/1

10YR 6/8 F2D Fe masses 1F C

1MSBK/ ABK

Btg3 130-160

10YR 6/1 -- -- -- -- SC 1MABK

BCg 160-191

10YR 7/1 -- -- -- -- C 0MA

Table 9c. Typical pedon description for Molena soils mapped at RCK (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-18 5YR 4/3 -- -- -- 3F S 0SGR

BE 18-46 5YR 4/6 -- -- -- 2F LS 1FGR few fine flakes of mica

Bt 46-130 5YR 5/6 -- -- -- 1F LS 2MGR few fine flakes of mica

C 130-152

5YR 5/8 -- -- -- 1F S 0SGR

common fine and medium flakes of mica

42

Table 9d. Typical pedon description for Dogue soils mapped at RCK (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


A 0-10 2.5Y 4/2 -- -- -- 3F L 2FGR

E 10-25 2.5Y 5/4 -- -- -- 3F, 3M L 1FSBK

Bt1 25-36 10YR 5/6 -- -- -- 2F CL 1MSBK few fine flakes of mica

Bt2 36-61 10YR 5/6 -- -- -- 2F C 2FABK few fine flakes of mica

Bt3 61-86 10YR 5/6

7.5YR 5/6 C2F Fe masses 1F CL 2MABK


10YR 6/2 C2P In matrix


Bt4 86-119 7.5YR 5/8 -- -- -- 1F CL 2FABK


10YR 5/1

2.5YR 4/6

2C 119-165

7.5YR 5/6

10YR 6/2 M2P In matrix -- LS/SL 0MA


Table 9e. Typical pedon description for Pamunkey soils mapped at RCK (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ap 0-23 7.5YR 4/4 -- -- --

3F, 3M SL 2FGR

3% rounded quartz gravel, few fine flakes of mica

Bt1 23-28 5YR 4/6 -- -- -- 3F SCL 2MSBK 1% rounded quartz gravel, few fine flakes of mica

Bt2 28-66 5YR 4/6 -- -- -- 2F CL 2MSBK 5% rounded quartz gravel, few fine flakes of mica

Bt3 66-109 5YR 4/8 -- -- -- 1F SCL 1COSBK 5% rounded quartz gravel, few fine flakes of mica

BC 109-117 5YR 4/8 -- -- -- -- SL 1FSBK

10% rounded quartz gravel, common fine flakes of mica

2C 117-203

10YR 5/6 -- -- -- -- S 0SGR

stratified layers, common fine flakes of mica

7.5YR 5/6 rounded greenstone and granite gravel

5YR 4/4 few cobbles

and triple super phosphate at a rate of 36 kg ha-1. In addition, existing vegetation (site was scrub-shrub/cut-over pine area) was ground and incorporated with the stripped topsoil to increase the organic matter content. The exact rate at which this organic amendment was applied is unknown, though it was reportedly spread to a thickness of 15 cm (Travis Crayosky, personal communication). Topographic variability has been implemented on this site by including depressional areas and swales, which also helps move water throughout the site and retain surface water

43

inputs longer. Wetland hydrology is expected to be maintained by a groundwater system supplemented by surface water runoff and fluctuating water levels in the adjacent natural system. Although there were no obvious problems encountered during construction, the proliferation of cattails post-construction has raised concerns. RCK is composed of three areas that are designated A, B, and C (Figs. 15 and 16). Area A is the most northern section. Forested wetlands in this zone were set at an elevation of 54.18 m, scrub-shrub at an elevation of 54.03 m, and emergent at 53.87 m. Area B is separated from area A by an unimproved road, and is south of area A. Forested wetlands in this area are set at elevations of 53.57 – 53.95 m, and emergent wetlands range at elevations from 53.42 – 53.8 m. Further west is area C, which is separated from area B by existing wetland. Elevations for the forested zones are from 52.82 – 53.8 m, and 52.81 – 53.49 m for emergent wetlands. Proposed forest species include boxelder, American hornbeam, black willow, and swamp white oak. Scrub-shrub species include buttonbush, swamp rose, and elderberry. 3.1.8 Sandy Bottom Sandy Bottom (SB) is located between I-64 and Hampton Roads Center Parkway, and is adjacent to the Sandy Bottom Nature Park in Hampton, VA (Figs. 17, 18a-b). Construction of the site began in November, 2002 and final grading operations of certain portions were still underway in mid-2004. SB is mitigation for impacts to forested wetland from the construction of the Hampton Roads Center Parkway and its extension of the East-West Expressway. SB is a mineral flat that is situated in the Coastal Plain over the Tabb formation (Rader & Evans, 1993). SB was once a site for sand mining operations, which left the site with deep lakes. Therefore much of the site was originally soil mapped as open water. However, the northern fringe of the site was mapped as Udorthents due to the disturbance history of the site.

Sandy Bottom is approximately 19.4 ha, where 90% is designed for forested wetland, 1% is shrub-scrub, and 4% is emergent wetland. Planting of the site occurred in the fall of 2004, and included forested species such as overcup oak, willow oak, bald cypress, and water tupelo. Scrub-shrub species included tag alder, arrowwood, and red chokeberry. The emergent wetland section contains lizard tail, cardinal flower, and Virginia iris. To achieve design elevations (5.5 – 7.0 m), which were based on adjacent wetland areas, filling and grading the old borrow pit areas were necessary, and as a result, minimal excavation of the site was required. Though the site was not designed to perch water above a limiting layer, the high clay content of the imported fill material has perched water in the surface layers in a dissimilar manner to the natural surrounding wetlands (DesPres, 2005). The soil was reconstructed by filling and compacting former borrow areas in lifts to an elevation of 15 cm below final design grades. The subgrade soil was limed (approximately 1.4 Mg ha-1) to adjust the pH of the soil to within the range of 5.5-8.0, which was required to satisfy DEQ’s discharge water quality standards (Steve Russell, personal communication). The placement of 15 cm of compost-amended topsoil (min. 4% organic by wt) was then added. Composted wood chips, which originated from stripped material from other unidentified VDOT projects, were used as an organic amendment. Very generic requirements were needed to satisfy the use of organic materials; the only stated condition was that no pieces over 8 cm could be used (Dean

44

Figure 17. Sandy Bottom site map.

45

Figure 18a. View of northeast section of SB near sample location 4.

Figure 18b. View of southeastern portion of SB near sample location 3.

Sample 3

46

Devereaux, personal communication). The topsoil was disked to a depth of 20 cm by making two passes across the site one time; one time in an east-west direction and the second pass in a north-south direction (Dean Devereaux, personal communication). No deep ripping occurred on-site; however, ripping supposedly occurred after our sampling. The soil was limed until the pH was within the same pH range as the imported subsoil. As there was no onsite topsoil available to the project, salvaged topsoil (from O, A, and E horizons) from various sources, including the Sentara Hospital construction site on Coliseum Drive and the 199 project in James City County, was used. This imported soil was pH-tested onsite. The design of this project does include gross topographic variability, as it includes pools, ridges, terraces, and flats. 3.1.9 Stony Creek Stony Creek (SCW; Figs. 19-20) is located off of I-95 and State Route 40 in Sussex County, Virginia. SCW is situated in the Coastal Plain physiographic province on Quaternary alluvial deposits. Like SB, SCW was a mining area that left the site as a deep pond. It was created as compensation for seven small maintenance projects and two large bridge replacement projects. Because SCW was a borrow pit lake, it was filled to accommodate a wetland environment. One hummock, as allowed by the USCOE, was incorporated into the site to establish some topographic variability. According to Dean Devereaux, only one hummock was permitted because VDOT wanted to create a washboard type system. The USCOE countered that it was too difficult to create and monitor that kind of system, and insisted that a flat tabletop surface be created instead. Thus the majority of the site was graded down to an elevation of 17.22 m.

In order to establish wetland hydrology, adjacent reference wetlands were used as a basis for the grading plan. Wetland hydrology was approved in May 1999, and planting occurred that following September. SCW was designed to support 14% emergent and 86% forested wetland. Planted forested species include bald cypress, pin oak, river birch, and black willow. Emergent species that were planted include pickerel weed and American bur-reed. To create wetland soils, imported topsoil was applied to the eastern leg of the site. The topsoil (O, A, and E horizons) was obtained from the previous owner of the site, who was a borrow pit operator that stripped and stockpiled topsoil. On the main body of the site, 10 cm of old sawdust was incorporated into in-situ material. The sawdust originated from a local lumber mill that had stopped operating 15 years ago (Dean Devereaux, personal communication). After the soil was graded to final elevations, and before planting occurred, the soil was disked to a depth of 15 cm and 400 kg ha-1 of lime was applied. Individual plantings also received fertilizer tablets. No deep ripping occurred on-site.

47

Figure 19. Stony Creek site map.

48

Figure 20. View of southern portion of SCW near sample location 3.

3.1.10 SW Suffolk/Lake Kilby

SW Suffolk (SWS; Figs 21, 22a-b) is located adjacent to Lake Kilby and Kilby Shores Subdivision in Suffolk, Virginia, and is compensatory mitigation for wetlands impacted by the construction of the four-lane SW Suffolk Bypass. SWS is situated on an excavated and filled flat within a side-slope of a broad interfluve between two unnamed drainages to Lake Kilby. It is located within the Coastal Plain region on the Suffolk Scarp, and the geology consists of the Chuckatuck formation (Rader & Evans, 1993). Soils mapped at this site include Suffolk loamy sand (Table 10) and loamy Udorthents within the disturbed borrow area. The Suffolk series consist of very deep, well drained soils on stream terraces, and subsequently forms in marine deposits and alluvium. They are classified as Typic Hapludults. The site was mainly used for sand mining operations.

The design of SWS involved the creation of two forested headwater wetlands on the

north and south sides of the site. Between these two zones exists a 46 m wide power line easement that runs east-west across the site. Microtopographic features were installed in the forested areas by including broad depressional flats, hummocks, and drainage swales. This site’s hydrology is mainly governed by groundwater inputs and surface flow during large storm events.

Because SWS was a borrow pit lake, it was filled in an average of 0.30 m, while the outer

areas of the original pit were cut an average 3.05 m. The grading plan achieved elevations of

49

Figure 21. SW Suffolk site map.

50

Figure 22a. Northern view of SWS near sample location 9.

Figure 22b. Eastern view of SWS near sample location 5.

51

Table 10. Typical pedon description for Suffolk soils mapped at SWS (Soil Survey Staff, 2004). All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Horizon Depth (cm)

Matrix Color

Redox Color

Redox Description


Ag 0-28 10YR 4/2 -- -- -- 3F, 3M LS 1MGR BA 28-41 10YR 5/4 -- -- -- 2F SL 1MSBK Bt1 41-51 10YR 5/6 -- -- -- 2F, 2M SL 1MSBK Bt2 51-74 7.5YR 5/6 -- -- -- 1F SCL 1MSBK Bt3 74-97 10YR 5/6 -- -- -- -- SCL 1MSBK BC 97-119 10YR 5/8 -- -- -- -- SL 1MSBK

C 119-165 2.5Y 6/4

7.5YR 5/8 F3D Fe masses -- LS 0SGR

7.38 – 7.62 m, which was decided upon after conducting a water budget analysis. At the time of construction, the contractor misinterpreted the plans and excavated too deep. As a result, they had to backfill with imported material, which came from the borrow pit that served the road project and the topsoil that was stripped and stockpiled. After topsoil was replaced, 457 m3 ha-1 of composted yard waste was disked in to achieve 4% organic matter content. At the time of seeding 1.2 Mg ha-1 of fertilizer (15-30-15) and 800 kg ha-1 of lime were applied to the soil. In addition, a total of 109 kg of slow release fertilizer tablets (18-6-12) were specified for individual woody plantings. No deep ripping occurred at SWS.

Wetland hydrology at SWS was approved in August 2003, and the site was subsequently planted in the fall of 2003. SWS is designed to support 85% forested, 9% scrub-shrub, and 6% emergent wetlands. Elevations for the forested wetland range from 7.32 – 7.62 m, and include species such as bald cypress, water tupelo, pond pine, and overcup oak. Scrub-shrub zones, located along the outer portions of the easement, are set at an elevation of 7.42 m, and consist of water loosestrife, swamp rose, and buttonbush. The emergent wetland is located directly beneath the transmission lines, and has an elevation of 7.38 m. PEM vegetation is comprised of species such as sago pondweed, fringed sedge, and creeping bentgrass. 3.2 Field Sampling The following sampling routine was originally conceived and performed by Michael J. Schmidt while at Virginia Tech as he sampled five sites (CCW, DC, MAN, MATTA, and SCW) in the summer of 2002. Subsequently, we sampled BCK, MTS, SB, and SWS in the late summer and fall of 2003, and finished sampling at RCK and SWS in April of 2004. Sampling locations were determined by electronically superimposing a grid on a digital image of the site map. Grid spacing was adjusted until there were 10 (e.g. CCW, DC, MAN, MATTA, MTS, SB, and SWS) to 14 (e.g. RCK) detailed sample locations for larger mitigation projects (i.e. > 4 ha). For smaller wetlands (< 4 ha: BCK and SCW), sample numbers were reduced so that there was at least 1 sample per 0.5 ha. This was achieved by designating each node within the boundaries of the created wetland as a sample location. Therefore, the number of nodes on the grid equaled the number of sample locations. Because it is established that forested wetlands are one of the most difficult systems to recreate (NRC, 2001), we wanted to focus our attention on soil properties in

52

areas designated as forested wetland. Thus, our sampling excluded ponded, emergent, and very wet shrub-scrub areas. Therefore, this sampling design was a stratified completely randomized design with sample locations randomly chosen within designated forested planting zones.

Actual sampling locations were located as close as possible to the pre-determined map grid points via field GPS technology and photo/map interpretation. At each point, a detailed soil description location (by auger) was chosen to be typical of what was within the surrounding 10 m (based on vegetation, surface conditions and elevation). If the grid location was in standing water (> 10 cm), all samples except the composite surface samples were instead taken from closest non-ponded soil. This lateral shift was done due to the difficulty in collecting auger and bulk density samples from zones beneath standing water.

Sampling locations were pin flagged (adjacent to auger description) and recorded via GPS using a Garmin eMap unit (15 m RMS accuracy). Other pertinent site information such as location, date, weather, surface conditions, vegetative cover, were logged into a bound data book. Digital images were taken of the typical vegetation and surface conditions. Then the following procedures were carried out:

1. A sample boring was augered to a depth of 1.5 m with an 8 cm diameter auger into a tray (except where limited by bedrock, cobble layers, or running sediment). The soil was described by horizon for color, structure, rooting depth and redoximorphic features using a soil description data sheet from Vepraskas (1992) and the Hydric Soils Manual (Hurt et al., 1998) (i.e. pore linings, depletions, concentrations, etc). Subsequently, a sample of each delineated horizon was placed into a plastic bag and taken to the lab for further analysis. If more than > 1 cm of O horizon litter was present, it was also described by layer (L, F, H) and collected. Digital images were taken of the profile and certain horizons (e.g. Fe concentrations/depletions).

2. Three surface bulk density samples were taken after moving aside vegetation and

litter. Since the bulk density hammer used required the uppermost portion of the core to be discarded, sample depths typically began at 3 to 5 cm.

3. With a sharpshooter, either the A horizon and/or whatever surface substrate was

present down to a depth of 25 cm was carefully removed. This was accomplished in "one square plug" in most cases by pushing the sharpshooter down in a square around the sides and then excavating the plug intact. A representative surface was then prepared for description with a soil knife. Using a Munsell color book, the 25 cm cube of soil was examined for redox features of oxidized rhizospheres, Fe-masses, and Fe-depletions with depth, and their colors, abundance, size, contrast (see App. B), and location (e.g. on roots) were noted in a field notebook and/or soil profile sheet. Pictures were taken of any notable features. If it was not possible to excavate the full 25 cm (due to bedrock, traffic pan, etc), a note of this was made in the field book.

4. Three bulk density cores were subsequently taken from the bottom of the 25 cm mini-

pit. On a few occasions (e.g. shallow bedrock at Manassas), deep bulk density

53

samples could not be taken. All bulk density samples were roughly trimmed to the ring in the field, with final trimming performed in the lab.

5. Using a soil probe, a composite sample of the 0-15 cm of soil from ten random

locations within a 10 m circle of the plot center was taken. This sample would allow for a broader comparison of soil properties across the grid locations and would address any point sample variability that might come with the point auger sample.

6. Proceed to next sampling location.

3.3 Laboratory Methods Soils were sampled by horizon and brought to the laboratory. After the collected soil samples were air-dried, they were ground through a 2 mm sieve and stored for further chemical analysis. To assess texture, particle size analysis via the pipette method was used (Soil Survey Laboratory Staff, 1996). The dry combustion method was used to ascertain soil carbon (Soil Survey Laboratory Staff, 1996), and acid extractable nutrients (P, K, Ca, Mg) and micronutrients (Zn, Mn, Cu, Fe, B), and pH were determined (Virginia Cooperative Extension, 1994). Bulk density was determined on intact soil sample cores (Blake & Hartge, 1986). 3.4 Statistical Analysis After field sampling and laboratory analyses were completed, the resulting data were entered into a spreadsheet. Variables included in the data set were pH, %C, %N, C:N ratio, macronutrients (Ca, K, Mg, P) and micronutrients (B, Cu, Fe, Mn, Zn), %sand, silt, and clay, bulk density, and mass C. Mass C is an estimate of the actual total mass of carbon (Mg C ha-1) within the soil, and was calculated by using the layer based method (Kathryn Haering, personal communication; Zhong et al., 2001):

Mass C (Mg ha-1) = TiυiCi[1-(δi/100)] where Ti is the thickness (cm) of layer i, υi is the bulk density (Mg m-3) of layer i, Ci is the %C content in layer i, and δi is the percentage of rock fragments (>2 mm) in layer i.

Statistical analyses of each parameter were performed to examine whether any significant differences occurred across sites at a given depth, and between soil depths (surface vs. subsurface in augering) at a given location. When comparing the surface soil variables across sites, the composite samples were used, whereas the auger surface samples were used when comparisons were made with depth within a site.

SAS System for Windows, Version 8 (1999) was utilized to conduct statistical analyses. The Wilcoxon Rank Sum Test was used to compare variables across sites at a given depth (e.g. comparing pH values at the 0-15 cm depth at all sites) due to non-normal data and small sample sizes. The Wilcoxon Rank Sum Test is the nonparametric equivalent to the two-sample t-test, and is generally a better test to use when dealing with non-normal data and unequal or small samples (Iman, 1994). In order to normalize the data, Tukey’s multiple comparisons on the

54

ranks (obtained from the Wilcoxon Rank Sum Test) of the data were performed (Zar, 1999). The Wilcoxon Signed-Rank Test was used to compare variables within a site at different depths (e.g. comparing pH at the 0-15 cm depth to the 30-45 cm depth at CCW). This nonparametric test is comparable to the paired t-test, and has more power than the paired t-test when normality is not satisfied (Iman, 1994; Zar, 1999). Differences were considered significant when P ≤ 0.05.

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4. RESULTS AND DISCUSSION 4.1 Wetland Summary 4.1.1 Butcher Creek Herbaceous vegetation dominated this site, and was a mixture of wetland and upland species. Location 3 was the most vegetatively robust, as American elm and sycamore saplings dominated the area. However, many of the planted trees were dead or stressed, which appeared to be related to a recent flooding event. Water marks were located as high as 1.2 m on the trees, and flattened vegetation and silty overwash were apparent. The soils at BCK (App. C) consisted of a truncated alluvial subsoil layer capped by a topsoil layer. A representative pedon (Table 11) had an A horizon that extended to a depth of 12 cm, a silt loam texture, and consisted of a strong coarse granular to subangular blocky structure. In addition, many fine roots were present, and prominent, dark reddish brown pore linings (Fe-concentrations) were common in the A horizon. Sampling locations 5 and 6 had the darkest A horizons, while the rest of the locations were typically brown or dark yellowish brown (Appendix B). Because locations 5 and 6 were closest to the road, it is most likely that the topsoil was stockpiled in these areas and then spread out to the rest of the site. Bulk densities in surface soils ranged from 0.98-1.59 g/cm3 (average shown in Figure 23a). Table 11. Representative pedon at BCK. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Location Horizon Depth (cm) Matrix Color Redox Color

Redox Description Redox Location Roots Texture Structure Comments

1 Ap 0-12 10YR 4/4 5YR 3/4 C1P Pore linings 3F SIL 3COSBK 5YR 2.5/1 C2P Pore linings 2.5Y 5/2 C3P In matrix 5Y 4/1 F3P In matrix 2BA 12-38 7.5YR 4/6 7.5YR 2.5/1 C2P Mn nodules -- SIL 3VFSBK 5Y 5/3 C1P Pore linings 2.5Y 6/1 F2P Along pores 2Bt 38-102 2.5YR 4/6 10YR 6/8 F1D Fe concretions -- L 3COSBK 10YR 5/6 2.5YR 2.5/1 F1P Mn masses N 7/0 C1P Along pores

2Btg 102-141 5Y 7/1 10YR 5/8 M2P Fe masses -- L 2COSBK

Although the surface horizon was rather uniform throughout the site, subsurface soils tended to be much more variable. Matrix colors include many hues of brown, and textures ranged from silt loam to clay loam to sandy loam. Soil structure was described as either weak to strong coarse subangular blocky or massive. Sampling locations 1, 4, and 5 exhibited the most horizon differentiation, as they consisted of 4-5 horizons. A gravel bed was encountered in sample 2, while locations 3 and 6 were underlain by massive C horizons. As a result, bulk density in subsurface horizons ranged from 1.62-1.87 g/cm3 (average shown in Figure 23b). Many types of redox concentrations (Fe/Mn masses, Fe concretions and Mn nodules, pore linings) and depletions (in matrix and along pores) were found in all soil horizons, although

56

those below the replaced A are most likely relict. While redox features were apparent at this site, no NRCS defined Hydric Soil Indicators were found.

Bulk density at 0-15 cm across sites

1.01.11.21.31.41.51.61.71.81.92.0

BCKCCW DC

MAN

MATTAMTS

RCK SBSCW

SWS

site

Bul

k D

ensi

ty (g

/cm

3 ) a

bbb

bc

cd dde

eff

Figure 23a. Average surface soil bulk density at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

Bulk density at 30-45 cm across sites

1.01.11.21.31.41.51.61.71.81.92.0

BCKCCW DC

MAN

MATTAMTS

RCK SBSCW

SWS

site

Bul

k de

nsity

(g/c

m3 )

a a a abbc

cc

d d d

Figure 23b. Average subsoil bulk density at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

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4.1.2 Charles City Charles City (CCW) vegetation varied from areas dominated by hydrophytes such as woolgrass and reeds (Locations 1, 4, 5, and 8), to intermediate wetness areas (2, 3, 9, and 10), to upland areas (Locations 6 and 7) dominated by upland grass and briars species. These differences seemed to be due to slight differences in elevation across the site and not to apparent differences in the soils. While there were significant areas present dominated by wetland vegetation, the plants were brown, dormant or dead by early to mid-summer 2002, with dry, hard cracked clayey soil surfaces. Although this was undoubtedly related to the regional drought of 2002, it raises the question of whether perennial herbaceous and woody wetland vegetation could have survived once the perched water table disappeared. The soils at all sampling locations appeared to be cut Chickahominy or Newflat subsoils, with the A, E, and likely some of the upper Bt or Btg horizon being removed. This resulted in truncated profiles, generally beginning with a revegetated Btg horizon serving as the surface layer. By convention, these surface horizons were described as A (see App. D), even though they clearly were formed in subsoil materials. A variable amount of “topsoil”, likely a mixture of the original A and E horizons was used as a cap (0-12 cm) thick, but the occurrence of this returned layer was highly variable across the site. While this cap provided a less clayey and compact growth medium, the naturally shallow A horizons of the Chickahominy and Newflat series as seen in the adjacent forested wetland (Schmidt, 2002) resulted in limited addition of organic matter and nutrients, especially after stockpiling and storage of the material. Combined with the drought prone hydrology, the low organic matter levels suggest compost or wood waste additions would potentially improve soil properties, water holding capacity, and plant survival. Redox features were observed in all the soil horizons, although most were probably relict. The presence of pore linings along some fine roots in many horizons suggested active reducing conditions. The well developed platy structure and high bulk density in the upper Btg horizon most likely had a negative effect on plant growth and rooting, especially when the soil dried. This traffic pan was likely caused during the construction of the wetland and is somewhat variable in lateral extent. Sample locations 1-5, 7, and 10 had confirmed Hydric Soil Indicators as they all had a depleted matrix (F3). 4.1.3 Dick Cross The vegetative patterns at DC follow the contours of the topographic variations in the wetland design, where the wetland is divided into cells separated by slightly higher bands (approximately 10 cm higher). Superimposed over the topographic banding, the southern portion of the main wetland is wetter, so the typical vegetation varies from cattails in both the cells and the higher bands (locations 8-10), to upland vegetation on the bands with reeds, sedges, and cattails in the cells, to lespedeza dominated drier areas (locations 3 and 4). The unconnected eastern portion of the wetland was also drier and dominated by lespedeza (location 2), while the area north of the access road was relatively wet (location 1). The mitigation area with the “oxbow feature” (location 5) was inaccessible for soil sampling due to the high water in the oxbow. The soils at Dick Cross consist of truncated alluvial subsoil capped by a topsoil layer (see App. E). Pre-existing relict Fe-masses and depletions were seen in the subsoil of the soil profiles. Active redox features, namely pore linings along some roots in the A horizon, were

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only seen in the wetter portions of the wetland (locations 1, 7, 9, and 10). Similar to other mitigation wetlands, most pedons exhibited high bulk densities, likely associated with construction traffic. Sample locations 3 and 7-9 had Hydric Soil Indicators with a depleted matrix (F3). 4.1.4 Manassas There were large portions (approximately 40-50%) of MAN dominated by upland species, such as lespedeza (locations 1, 3, 4, 7, and 9), while other areas had typical wetland vegetation such as reeds, sedges, and cattails. The area where Cockrell Branch enters the wetland (location 5) is especially wet and characterized by hummocks of reeds and standing water. At the time of sampling (July, 2002), beavers may have contributed to the drier than anticipated site by diverting water from the northern portions of the wetland. Plans were being made to return the flow to the wetland and some additional grading. There also have been some problems with erosion on cut banks surrounding the wetland. A common characteristic of MAN is shallow red shale bedrock (20-94 cm). A typical profile (see App. F) contained an A horizon over compact red clay subsoil with some redox features, such as Fe depletions in the subsoil or pore linings in the surface. However, only two locations (1 and 4) met the red parent material (TF2) Hydric Soil Indicator. Similar to other mitigation sites, soil compaction is a concern in many areas of the wetland. An exception to these high bulk density soils was the cattail-dominated location 10. This particular sampling location had abundant roots to a depth of 13 cm, which may have helped improve soil conditions. 4.1.5 Mattaponi At the time of sampling (May, 2002), MATTA had not yet received its final seeding and planting, so it was difficult to assess the site based on vegetation alone. Besides the barren cut bank areas (due to active oxidation of acid sulfate materials) and the submerged areas, the site was dominated by perennial rye and weedy volunteer species. Similar to DC, topographic variation was designed into the site, with alternating scroll bands with approximately 15-25 cm difference from crests to swales. Over much of the site, this resulted in relatively dry islands, with perennial rye stands surrounded by 10-30 cm of standing water. The soils at MATTA (see App. G) were fairly similar to each other, yet there were some variations likely associated with different depths of excavation and/or variation in original sedimentation moving away from the Mattaponi River. All sampling locations were capped with topsoil mixed with wood mulch, which was stockpiled onsite at the time of sampling. Below this cap, there usually were alluvial gravelly or sandy horizons. In locations where deep augering was not inhibited by cobble layers or running sand layers that caved in at the water table, a dark gray deposit with common mica flakes was observed at approximately 25 cm. In several cases, white shell fragments were also found in the deepest parts of this dark gray layer. Because some of the locations (5-8) had > 60% gray colors within 25 cm, they met the depleted matrix (F3) hydric soil indicator. While returning topsoil with organic matter additions should improve mitigation success, it may also lead to certain problems. The stockpiling, mixing and reapplication of the topsoil appeared to have destroyed aggregation and created a massive replaced A horizon with high bulk

59

density. Although this may improve with time as soil structure develops, this surface compaction may be a concern in the short-term, especially on the drier islands where high bulk density is more likely to affect rooting and rainfall infiltration. 4.1.6 Mount Stirling Mount Stirling (MTS) is a 3-terraced wetland site, where the southern portion of the site is the highest in elevation, and the northern area is the lowest (see Fig. 13). The site is dominated by wetland (FAC to OBL) species, such as rushes and red maple. Berms separate each terrace, and are vegetated by upland species, such as lespedeza. The southern portion of the site tended to be much wetter than the northern section. The water table was reached within 30 cm in locations 1-3, while most of the remaining samples had the water table starting at 1.22-1.52 m. At the time of sampling, the bulk density ranged from 1.31-1.82 g/cm3 in surface soils to 1.76-2.01 g/cm3 with depth (see Figs. 23a & 23b for averages). The soils at MTS are truncated alluvial soils capped with topsoil (see App. H). The soils at locations 1-3 were not very well developed, since they had loamy sand Ag horizons overlying structureless (single-grain) C horizons. The soils progressively became more variable and structured towards the northern end of the site as relict Bt and BC horizons were present. The typical Ag horizon extended to 20 cm, was dark grayish brown, had strong coarse granular structure, and common to many very fine and fine roots. Strong brown pore linings (Fe-concentrations) were common and distinct or prominent in the A horizon. As a result, over half of the samples taken met a Hydric Soil Indicator. Soils at locations 1 and 2 met the sandy redox (S5) field indicator, while locations 3, 6, 9, and 10 met the depleted matrix (F3) field indicator. 4.1.7 Reedy Creek Cattails, sedges, and rushes dominated the relatively flat site, with some depressional areas that contained emergents. Berms bisect sections B and C, where lespedeza and other upland species have proliferated. In the southern portion of Section A (location 12), water was ponded at the surface. Due to the saturated conditions, deep bulk density samples could not be taken here. The northern part of A was slightly higher in elevation. The southern area of Section B and C was wetter than the northern portion, since it was lower in elevation and closer to the water table. The soils at RCK were truncated alluvial soils capped with topsoil (see App. I), with the exception of sample location 9, which must have been overlooked when topsoil was re-spread over the site. The most commonly observed feature was the presence of a strong coarse angular blocky sandy clay loam layer located immediately below the A horizon. The angularity and compaction of this layer was probably a result of compaction through construction practices, and was done intentionally in Areas B and C so as to create a perching layer. The bulk densities at depth (30 cm) were 1.34-1.87 g/cm3 (see Figure 23b for average). Underneath this layer, the clay content dropped dramatically, as loamy sands and sands with high mica contents were observed at approximately 110 cm. Prominent Fe/Mn masses and redox depletions in the matrix were commonly detected.

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The sandy loam to loam topsoil layer was commonly dark grayish brown to light olive brown, and contained many very fine and fine roots. Prominent Fe/Mn masses and distinct to prominent strong brown pore linings were common, while few redox depletions in the matrix were observed. Bulk densities of the surface horizon ranged from 1.17-1.58 g/cm3 (see Figure 23a for average). Hydric soil field indicators were found in locations 1, 3 - 5, 7, 8, and 13, which met the depleted matrix (F3) field indicator. Locations 7 and 13 also met the Fe/Mn masses (F12) field indicator. 4.1.8 Sandy Bottom Vegetation at SB varied widely due to differences in age of grading, invading species, and wetness regimes. Clumps of wetland and upland species coexisted at many of the sample locations (4, 7, 9, and 10), while some locations (1 and 3) exhibited no vegetation, and others were sparse (5 and 8). Sample location 6 was the wettest site, dominated by sedges. Location 2, which was dominated by cattails, could not be sampled as it was inundated with water. This disparity in vegetation and wetness was due to obvious and distinct local differences in elevation. SB soils (see App. J) consisted of highly compacted, filled marine sediments (1.59-2.09 g/cm3) capped with extremely compacted topsoil (1.76-1.88 g/cm3, see Figures 23a & 23b for averages). A typical pedon (Table 12) had a very dark gray sandy loam A horizon, with strong fine granular structure that extended down to a depth of 12 cm. No redox features were found in the A horizon, indicating either that insufficient time has passed for these features to develop or the soil is not potentially hydric. However, under this topsoil was a dark grayish brown sandy loam 2BAg horizon. In this subsoil layer, relict redox features (common to many, distinct and prominent Fe/Mn masses and redox depletions in the matrix) from the imported fill were noted. As a result, over half of the locations met the depleted matrix hydric soil field indicator (F3; samples 1, 3, 7, 8, 9). Underneath this 2BAg layer was a sandy clay loam 2Bt horizon, which in conjunction with the compact nature of the soil, presumably aided in the development of a depleted matrix, as the higher clay contents would impede downward water movement, and subsequently cause perching. Clay contents dramatically decreased downward, as the deeper subsoil layers tended to be loamy sands or sands. Table 12. Representative pedon at SB. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).

Location Horizon Depth (cm)

Matrix Color Redox Color

Redox Description


9 Ap 0-17 10YR 3/1 -- -- -- 1M SL 3MSBK

2BAg 17-40 2.5Y 4/2 10YR 5/6 C3P Fe masses -- SL 3COSBK 15% shells

N 3/0 F3P Mn masses

2Bt1 40-75 2.5Y 5/4 5B 5/1 C3P In matrix -- SCL 2COSBK 50% shells

2Bt2 75-96 10YR 5/4 5GY 4/1 C2P In matrix -- SCL 3COSBK 50% shells

2Btg 96-127 5B 5/1 10YR 5/8 M1P Fe masses -- CL 3COSBK

2BC 127-150+ 10YR 5/8 2.5Y 4/1 C3D In matrix -- SCL 3COSBK 50% shells

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4.1.9 Stony Creek Stony Creek (SCW) was constructed from an old gravel mine and features a large pond in the intersection of the two arms of the L-shaped wetland. The herbaceous vegetation typically was a mixture of wetland and facultative wet species. Since the tree saplings were planted in blocks, it was possible to compare the relative success of different species. The black willow, bald cypress, and river birch seemed successful relative to the stunted or dead oaks and water tupelo. Combined with observations from other mitigation wetlands, this suggests selecting early successional colonizer tree species for planting may be more effective than trying to recreate a similar species structure as mature forested wetlands (Spencer et al., 2001). It was difficult to find similarities among the soil profiles onsite, likely due to the site history of sand and gravel mining. One common feature was the hard, compact, and often platy surface horizon (see App. K). This high bulk density horizon is likely a traffic pan, and may pose some problems for rooting. At sampling locations 1-3, organic material (compost or ground wood waste) was added to the surface soil. This reduced the bulk density to 0.75-1.43 g/cm3 compared to 1.63-1.95 g/cm3 for locations 4-6 (see Figures 23a & 23b for averages), and suggests organic amendment and incorporation as a method for ameliorating high bulk densities from wetland construction. Four out of 6 samples met a hydric soil indicator. Because location 3 had a sulfur smell within 30 cm of the surface, it met the hydrogen sulfide (A4) soil indicator. Location 4 had sandy redox (S5) features, while 5 and 6 contained a depleted matrix (F3). 4.1.10 SW Suffolk The vegetation at SWS was a mixture of wetland and upland species at most sampling locations, except for locations 9 and 10. These locations were slightly lower in elevation, thus wetter, and supported wetland species such as cattails and reeds. Those locations with mixed vegetation included sedges, reeds, cattails, clover, and crabgrass. The water table at this site was observed at a depth of 1.22-1.52 m. Soils at SWS (see App. L) varied somewhat, most likely due to the mining and disturbance history of the site. Subsoil textures ranged from very coarse sand to sandy clay loam, and structures were weak to strong subangular blocky, massive, or single grain. The soil at location 4 had hydrogen sulfide odor with depth, signifying deeply anaerobic conditions. One similarity in common, however, was that the majority of pedons contained a gleyed matrix at their depth, which indicates that SWS is a groundwater fed site. Also, Fe/Mn masses, pore linings, and depletions in the matrix were commonly observed. Bulk density in the subsoils ranged from 1.67-1.99 g/cm3 (see Figure 23b). Despite these differences observed in subsoil layers, the topsoil capping was similar at all sampling locations. The sandy loam A horizon was characterized as having a very dark gray to black color; a direct result from having added organic materials mixed into the topsoil. It extended to a depth of 19 cm, contained many very fine and fine roots, and bulk density ranged from 1.23-1.69 g/cm3 (see Figure 23a for average). Common Fe masses and few pore linings were observed in the A horizon. Hydric soil field indicators were found at some locations. Locations 7 and 9 met the depleted matrix (F3) field indicator, while location 2 met the hydrogen sulfide (A4) indicator.

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Several small (<100 m2) pockets of dead vegetation and bare soil with common red iron oxide surface floc did occur at SWS, indicating the presence of acid sulfate soils. Some remediation should take place to raise the pH of these dead spots, since grab samples showed a soil pH of 2.8. However, this should not be a major concern as long as the soils remain saturated, which will help to keep sulfides reduced. 4.1.11 Summary of Hydric Soil Occurrence

Although the depleted matrix indicator was met at some of the soil locations, it is doubtful that they formed under their current conditions. According to Vepraskas et al. (1999), it takes at least five years for a depleted matrix to form. Since all of the sites had not reached that age by the time they were sampled, it can be said with reasonable certainty that those soils were already depleted when the wetland was created. Soil excavation just brought them closer to the surface, which resulted in their meeting the F3 Hydric Soil Indicator. Table 13 summarizes the hydric soil reconstruction success with respect to occurrence of “proof positive” Hydric Soil Indicators in this study.

Table 13. Hydric Soil Indicator occurrence in 10 young VDOT wetlands.

Site Number of Sampled Pedons

Number of Pedons Meeting a Hydric

Soil Indicator

Percent (%) of Pedons Meeting a Hydric Soil

Indicator BCK 6 0 0 CCW 10 7 70 DC 9 4 44 MAN 10 2 20 MATTA 10 4 40 MTS 10 6 60 RCK 14 7 50 SB 9 5 56 SCW 10 4 40 SWS 6 3 50 TOTAL 94 42 45

4.2 Soil Chemical Properties 4.2.1 pH Sandy Bottom (SB) had the highest pH (6.6) in the surface, and was similar to SWS, MATTA, and RCK which had a pH of 6.3, 6.2, and 5.8, respectively (Figure 24a). The remaining sites had relatively uniform surface pH levels that ranged from 5.3 – 5.7 (overall p<0.0001). At the 30-45 cm depth, SB had the highest pH of 6.7, while MATTA exhibited a low pH of 3.7 (Figure 24b; overall p<0.0001). Dick Cross (DC) contained the highest pH (6.0) at the 90-105 cm depth, and was similar to four other sites (Figure 24c; SCW, SB, RCK, and BCK). Mattaponi (MATTA) had the lowest average pH of 2.8 at this depth (overall p<0.0001), and was obviously in sulfidic materials (Orndorff, 2001). Over half of the sites showed no differences in pH with depth. Significant contrasts that were observed occurred primarily between the surface and subsurface layers (30-45 cm and 90-105 cm, see App. L) at CCW, MATTA, RCK, and SWS. Differences in pH were also seen between the surface and 90-105 cm at MTS.

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Overall, all sites had a relatively high pH at the surface (adjacent natural wetland soils had an average surface pH of 4.5 (Doug DeBerry, personal communication)) because lime amendments were routinely added to the surface at most sites during final soil reconstruction. This pH range could maximize macronutrient availability, but could also reduce micronutrient solubility. In addition, organic matter decomposition tends to increase as pH nears neutrality since these conditions are more favorable for microbial activity (Collins & Kuehl, 2001), and may inhibit redoximorphic feature formation by reducing Fe and Mn solubility (Cummings, 1999; Tisdale et al., 1993). These trends seem to be quite common in other created wetlands as well. Nair et al. (2001) studied phosphate-mined created wetlands in Florida, and found that the pH at these sites were near neutral to slightly alkaline due to an increase in available Ca. Stolt et al. (2000) compared three paired wetlands in Virginia, and concluded that the pH was higher in created wetlands. Bishel-Machung et al. (1996) also reported higher pH in created wetlands in Pennsylvania. Stolt et al. and Bishel-Machung reasoned that created wetland soils have a higher pH because the subsoil layers (that become the surface via excavation to the predicted water table) had not been exposed to the same level of organic acids and long term intensity of weathering processes. For these reasons, most of the sites observed in this study showed no pH difference with depth.

However, those sites that showed differences with depth apparently were due to the

occurrence of sulfidic materials, which are particularly abundant in lower Tertiary deposits of the Coastal Plain (Orndorff, 2001), and were confirmed at MATTA. When sulfidic materials come into contact with oxygen, a complex set of reactions is initiated, with the end product being sulfuric acid. In the presence of these strongly acidic conditions (pH<4) micronutrient toxicity and reduced plant growth and mortality can occur. In order to correct these conditions, large

Surface pH (0-15 cm) across sites

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

BCK CCW DC MAN MATTA MTS RCK SB SCW SWSSite

pH

a aa

abbc bc

bcc cc

Figure 24a. Average pH at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

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pH (30-45 cm) across sites

3.0

3.5

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4.5

5.0

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8.0


pH

a

ab ab ab ababbc bc

c

c

Figure 24b. Average pH at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

pH (90-105 cm) across sites

2.0

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BCK CCW DC MATTA MTS RCK SB SCW SWS

Site

pH

aa

a

ab abc

bcd bccd

d

Figure 24c. Average pH at 90-105 cm at each site. Different letters above treatment bars indicate differences at p≤0.05. Apparent irregularities in significant differences are due to unbalanced n values, which results in lack of power across certain pairwise contrasts.

65

quantities of lime are necessary, which in the end can be quite costly. Thus, great care should be taken to avoid exposure and oxidation of sulfidic materials. 4.2.2 Acid Extractable Nutrients Acid extractable macronutrient levels (P, K, Ca, and Mg) varied widely at all depths (overall p < 0.0001; Table 14). At the 0-15 cm depth, P contents in the soil ranged from as low as 2 mg/kg in CCW to as high as 58 mg/kg in SWS. In the subsurface, P levels ranged from 1 mg/kg in CCW (both depths) to 108 mg/kg at the 30-45 cm depth and 183 mg/kg at the 90-105 cm depth in MATTA. For K, SWS had the highest levels at both the surface and 30-45 cm depth (237 and 127 mg/kg, respectively), while MATTA had the highest contents (118) at the 90-105 cm depth. MTS had the lowest K content at the surface (22 mg/kg), whereas DC had the lowest levels in both subsurface depths (10 and 10 mg/kg, respectively). For Ca, contents ranged from 445 mg/kg (DC) to 2221 mg/kg (SB) at the surface, 88 mg/kg (CCW) to 2609 mg/kg (SB) at the 30-45 cm depth, and 67 mg/kg (CCW) to 2109 mg/kg (MATTA) at the 90-105 cm depth. Extractable Mg levels varied from 83 mg/kg (MTS) to 252 mg/kg (CCW) at the surface, 58 mg/kg (MTS) to 313 mg/kg (MAN) at the 30-45 cm depth, and 46 mg/kg (MTS) to 384 mg/kg (DC) at the 90-105 cm depth.

When comparing the surface to both subsurface depths within a site (Appendix M), only CCW, MATTA, and SWS showed differences in P levels. Half of the sites (DC, MATTA, RCK, SB, and SWS) exhibited depth differences in K content, while more than half (CCW, MATTA, MTS, RCK, SB, and SWS) demonstrated differences in Ca levels. Finally, CCW, DC, RCK, SCW, and SWS showed significant differences in Mg content.

According to Virginia Cooperative Extension (1994), an agricultural soil should contain approximately 11-15 mg/kg P, 51-75 mg/kg K, 481-600 Ca, and 49-60 mg/kg Mg for optimal plant growth. As such, half of the sites (BCK, CCW, DC, MAN, and RCK) were generally deficient in P, and six sites (BCK, CCW, DC, MTS, RCK, and SCW) contained inadequate amounts of K. In contrast, P and K levels were very high at SWS and MATTA. The P results were probably affected by acid-soluble P found in some of the young or unweathered sediments, while the high K levels are probably an indication of the overall lack of weathering in many of these materials. In addition, all sites had very high levels of Ca and Mg, which can be attributed to the lime amendments and/or pre-existing soil conditions (e.g. presence of carbonates at SB and blue marl at depth at MATTA).

Micronutrient (Zn, Mn, Cu, Fe, and B) levels appeared to be sufficient at all sites and depths; however, some sites exhibited higher than normal contents. These higher levels are most likely related to the nature of the parent material, rather than to any amendment practices that were performed. For example, MATTA had the highest levels of Zn and Fe within both subsurface depths, signifying the presence of sulfidic materials (e.g. sulfides, pyrites), which was further confirmed by the pH results (see Figure 24) discussed earlier.

It is important to point out that soil sufficiency levels as cited above are based upon uptake correlation studies for various agronomic and horticultural species rather than the native

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Table 14. Comparison of acid-extractable nutrients across sites. Values for a given element by sample depth are different (p < 0.05) when followed by differing letters. Apparent irregularities in significant differences are due to unbalanced n-values, which results in lack of power across certain pairwise contrasts. P K Ca Mg Zn Mn Cu Fe B Site --------------------------------------------------mg/kg-----------------------------------------------------

0-15 cm BCK 3.5d 39cde 659c 107bc 3.5b 43bc 6.5a 154abc 0.25cd CCW 2.0d 37de 520c 252a 1.3cd 110b 1.1c 30d 0.22cd DC 3.7d 47cd 445c 122bc 1.0d 50bc 1.1c 64cd 0.17d MAN 3.6d 62c 720c 149b 1.1cd 66bc 1.3c 108cd 0.35b MATTA 43.2b 119b 793c 148b 4.0b 100b 1.0c 94cd 0.40b MTS 14.8c 22e 477c 83c 3.6b 16c 5.4a 200ab 0.19cd RCK 2.8d 38de 518c 153b 2.0c 176a 3.8b 225a 0.21cd SB 15.2c 54cd 2221a 138b 1.2cd 18c 1.0c 84cd 0.27c SCW 9.5cd 39de 516c 133bc 1.7cd 52bc 1.0c 115bcd 0.17d SWS 58.1a 237a 1525b 240a 7.3a 17c 1.5c 106cd 0.72a

30-45 cm BCK 3.1c 33c 529c 197bcd 2.0b 39a 5.4a 73b 0.16bc CCW 1.0c 31c 88c 125de 2.2b 10c 1.4c 25b 0.11c DC 2.8c 10c 343c 277ab 1.4b 9c 1.0c 38b 0.10c MAN 1.0c 16c 387c 313a 1.2b 20abc 0.6c 27b 0.10c MATTA 107.9a 83b 1346b 194cd 6.0a 36a 0.7c 575a 0.18ab MTS 12.3bc 23c 281c 58f 2.6b 10c 5.7a 108b 0.10c RCK 2.2c 18c 344c 244abc 1.4b 29ab 2.4bc 37b 0.11c SB 7.7c 36c 2609a 84ef 0.8b 11c 0.6c 74b 0.24a SCW 44.4b 25c 419c 90ef 1.0b 34ab 0.8c 112b 0.10c SWS 16.1bc 127a 437c 79ef 5.7a 17bc 4.0ab 128b 0.24a

90-105 cm BCK 2.0cd 13d 674bc 323ab 1.9bcd 23bcd 6.2a 26c 0.10c CCW 1.0cd 37c 67c 161cd 3.3bcd 4cd 1.7b 29c 0.10c DC 4.9cd 10d 430bc 384a 1.9cd 8cd 1.2b 34c 0.10c MATTA 183.3a 118a 2109a 259bc 8.3a 54a 0.8b 830a 0.25a MTS 7.6cd 18.4d 293bc 46e 1.7d 1d 4.4a 69c 0.10c RCK 2.4d 15d 279c 266b 1.3d 11cd 1.9b 29c 0.10c SB 7.4cd 30c 1958a 76de 6.4ab 7cd 0.9b 153bc 0.16b SCW 76.4b 33c 444bc 78de 1.1cd 25bc 0.6b 171bc 0.12bc SWS 89.6b 52b 907b 109de 5.3abc 32b 2.4b 262b 0.14b

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plant materials utilized in created wetlands, which presumably would have much lower nutrient demands. Furthermore, the nutrient correlation studies used to establish soil sufficiency levels almost exclusively analyze naturally occurring topsoil materials under agricultural management rather than the widely variable mixes of returned topsoil, subsoil and deeper geologic media that were encountered in my sampling of these ten wetlands. Therefore, a highly variable range of acid extractable nutrients was to be expected in this study and direct comparison to standard soil sufficiency levels is not valid. 4.2.3 Soil Carbon Content Soils at SCW and SWS had the highest %C at the surface (0-15 cm), with an average of 2.59% and 2.32%, respectively (Figure 25a). The remaining sites contained <2%, with DC having the lowest %C content in the surface at 0.85% (overall p<0.0001). Interestingly, SCW was one of the wettest sites sampled, presumably providing suitable conditions for anaerobiosis and C retention. At some locations within SCW (main body), H2S odor was evident, which further indicated that strongly anaerobic conditions were present. As a result, organic matter processing and decomposition by the microbial biomass was repressed. The main body of SCW, where organic amendments were used, had particularly high C contents (3.4 - 4.9%), compared to those found at the eastern leg of the site (0.9-1.7%), which did not receive organically amended topsoil. Similar to SCW, SWS also had the distinctive H2S odor in some areas. However, the %C levels did not quite match that of SCW, as the highest amount found was 3.3%. Because of the age difference between these two sites, it is most likely that anaerobic conditions in SWS have not persisted for as long cumulatively as that of SCW.

Carbon content at 0-15 cm across sites

0.00.20.40.60.81.01.21.41.61.82.02.22.42.62.8


%C

aa

ab

bc bcc ccc

c

Figure 25a. Average %C at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

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0.0

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0.6

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a

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bcdcd

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Figure 25b. Average %C at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.


0

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BCK CCW DC MATTA MTS RCK SB SCW SWSSite

%C

aa

ab

b b b b

b

b

Figure 25c. Average %C at 90-105 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

69

In subsurface horizons (30-45 cm; Figure 25b), SB had the highest %C, at 0.8%, while MATTA had 0.5% at the 90-105 cm depth (Figure 25c). These values appear to be high for subsurface depths, and may be a result from the presence of carbonate-C in these particular samples, which can greatly increase the measured total-C content by the method utilized. All sites except for MAN showed significant differences between the surface and the 30-45 cm depth. The same was true (except BCK) when comparing the surface to the 90-105 cm depth. This agrees with Cummings (1999) and Stolt et al.’s (2001) findings that %C generally decreases with depth, and conforms to the basic soil formation theory (Jenny, 1941).

Comparing the average %C results to the typical %OM found in each site’s corresponding soil series (USDA-NRCS, 2004), revealed that %C may have increased at the surface (0-15 cm) and subsurface (30-45 cm) after the wetland was created (Table 15). The combination of added organic amendments at most locations coupled with longer saturation periods may have begun to limit decomposition, allowing %C to slowly accumulate. While most of the increases were slight (< 0.5%), SWS had almost a 2% difference at the surface, indicating that the fill type used consisted of soils with higher organic material. However, it is important to point out that the NRCS series data used here are averages based on sampled pedons at typifying locations (not my sites), and the pre-existing mapped soils were primarily upland soil types which would be expected to have lower C levels than found in hydric soils.

While %C, for the most part, increased at each site, these C levels are relatively low in comparison to natural wetlands. For instance, Atkinson et al. (1993) compared the carbon content in a paired forested wetland in the Piedmont region of VA, and found that the created wetland organic content was roughly half (1.87% vs. 4.67%) that of the reference wetland. Cummings (1999) also reported higher carbon contents in natural forested wetlands in the Coastal Plain of VA, finding as much as 4-6% in the surface compared to <2% in created wetlands. Although this research did not include paired reference wetlands, it can be deduced that these sites are on par with other created wetlands in VA with respect to retained C, but are not as high as natural forested wetlands.

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Table 15. Comparison of %C in mitigation site soils compared to pre-existing soil conditions per the USDA-NRCS Soil Survey Geographic Database.

Site* Average

%C

Typical %OM Reported by

NRCS

NRCS Data Reported as

%C**

NRCS Average

%C 0-15 cm BCK 1.96 1.0 - 4.0 0.58 - 2.32 1.45 CCW 1.08 0.5 - 3.0 0.29 - 1.74 1.02 DC 0.85 1.0 - 4.0 0.58 - 2.32 1.45 MAN 1.30 0.5 - 3.0 0.29 - 1.74 1.02 MATTA 1.14 0.5 - 3.0 0.29 - 1.74 1.02 MTS 1.08 0.5 - 6.0 0.29 - 3.48 1.89 RCK 1.16 0.5 - 4.0 0.29 - 2.32 1.31 SWS 2.32 0.5 - 1.0 0.29 - 0.58 0.44

30-45 cm BCK 0.54 1.0 - 3.0 0.58 - 1.74 1.16 CCW 0.19 0.0 - 0.5 0.0 - 0.29 0.15 DC 0.17 1.0 - 3.0 0.58 - 1.74 1.16 MAN 0.18 0.0 - 0.5 0.0 - 0.29 0.15 MATTA 0.39 0.0 - 0.2 0.0 - 0.12 0.06 MTS 0.33 0.0 - 1.0 0.0 - 0.58 0.29 RCK 0.18 0.0 - 1.5 0.0 - 0.87 0.44 SWS 0.62 0.0 0.0 0.00 90-105 cm BCK 0.33 1.0 - 3.0 0.58 - 1.74 1.16 CCW 0.12 0.0 - 0.5 0.0 - 0.29 0.15 DC 0.14 1.0 - 3.0 0.58 - 1.74 1.16 MATTA 0.52 0.0 - 0.2 0.0 - 0.12 0.06 MTS 0.11 0.0 - 0.5 0.0 - 0.29 0.15 RCK 0.10 0.0 - 1.5 0.0 - 0.87 0.44 SWS 0.14 0.0 0.0 0.00

* No direct comparison is available for SB and SCW, as these sites were borrow pits at the time a soil survey was performed. ** To determine %C the following calculation was used: %C = %OM * 0.58 (Nelson and Sommers, 1982).

4.2.4 Total Nitrogen At the surface, SWS had the highest total N, with 0.17%, while DC had the lowest total N at 0.08% (overall p = 0.0003; Figure 26a). Total N ranged from 0.02% (SCW) to 0.05% (CCW) at the 30-45 cm depth (Figure 26b), and from 0.02% (RCK) to 0.05% (CCW) at the 90-105 cm depth (Figure 26c). As would be expected, total N tended to significantly decrease with depth (Appendix M) due to its direct relationship with C and the microbial biomass. Cummings (1999) reported similar results in her study of created forested wetland soils, while their natural counterparts were two to three times higher in total N. Stolt et al. (2000) also reported higher N levels in natural wetlands directly adjacent to VDOT mitigation sites, and these natural hydric soils contained as much as five to ten times as much N than created wetlands. Because total N and organic matter content are strongly correlated in wetland systems,

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Total nitrogen content at 0-15 cm across sites

0.00

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%N

a

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b b

b

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Figure 26a. Average %N at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.


0

0.01

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%N

a

ab ababcabcd

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Figure 26b. Average %N at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

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0

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BCK CCW DC MATTA MTS RCK SB SCW SWSSite

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abab

abcbc

c c cc

Figure 26c. Average %N at 90-105 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

it is not surprising that the total N levels were minimal. Until organic matter accumulates, I would expect %N to remain low. Since many plants are dependent on N for biochemical processes (e.g. photosynthesis), ongoing N deficiencies could result in limited productivity. 4.2.5 Carbon to Nitrogen (C:N) Ratio The C:N ratio at 0-15 cm ranged from 10.7 (MAN) to 24.7 (SCW; overall p < 0.0001; Figure 27a). At the 30-45 cm depth, C:N varied from as low as 3.5 (CCW) to 19.8 (SB; Figure 27b), and from 2.7 (CCW) to 15.7 (SB) at the 90-105 cm depth (Figures 27c). In addition, over half the sites showed a significant difference with depth (Appendix M). Generally, a C:N ratio < 25 is indicative of a stable and high quality organic matter complex, while higher C:N values would be indicative of conditions where fresh high C residues had been recently added and not fully decomposed at the time of sampling (Nair et al., 2001; Schmidt, 2002). Low C:N values also suggest that net N-mineralization is occurring because soil fauna are actively breaking down labile carbon sources, which releases the N content of the tissue.

Stony Creek (SCW) had the highest C:N value, which may be due to the type of organic matter amendment (sawdust) used. Woody material typically has high lignin content, which is highly resistant to breakdown. Sandy Bottom (SB) also exhibited a high C:N value, but this may be due to a carbonate error in the lab analysis since C:N remained consistent with depth. Nonetheless, all the sites studied had a C:N ratio < 25, suggesting that each had a relatively high quality and palatable litter source that was being actively turned over with time. This agrees with results reported by Nair et al. (2001).

73

C:N at 0-15 cm across sites

02468

10121416182022242628

BCK CCW DC MAN MATTA MTS RCK SB SCW SWS

Site

C:N

a

b

bc

cc

c c c

c c

Figure 27a. Average C:N at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.


0

2

4

6

8

10

12

14

16

18

20

22


Site

C:N

a

bb

bcbc

cdcde cde

dee

Figure 27b. Average C:N at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

74


0

2

4

6

8

10

12

14

16

18


Site

C:N

a

a

ab

bbc bc bc

bc

c

Figure 27c. Average C:N at 90-105 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

The very low values of C:N (< 8:1) in the subsoil layers are puzzling. These values

indicate relative enrichment of total-N with respect to C in these deeper horizons. This could have been due to fixed ammonium in mica interlayers or residual effects of initial site fertilization and ammonium retention by clays. Since the C levels are so low, it would only take a relatively small mass of total-N present at these depths to generate these unusual values. 4.2.6 Mass Carbon Mass carbon is a variable that is rarely determined in wetland studies; however, it is an important parameter to document since soil organic C is a major active pool in the global C cycle. As mentioned previously, mass C is an estimate of the actual total mass of carbon (Mg C ha-1) within the soil.

As expected, the mass C findings were similar to observed differences in %C across sites, where SWS and SCW had the highest contents at the surface, with 50 and 48 Mg ha-1, respectively (Figure 28a). Soils at DC contained the lowest surface amount, having only 20 Mg ha-1 (overall p<0.0001). Soils at MATTA contained the highest mass C in both subsurface depths (Figures 28b and 28c), with 56 Mg ha-1 within the 30-45 cm depth and 97 Mg ha-1 at 90-105 cm. Like %C, these values seem rather high for subsurface depths, and probably can be attributed to carbonate-C content. SCW had the lowest mass C in the 30-45 cm depth, with 8.9 Mg ha-1 (overall p=0.0003), whereas RCK had the lowest mass C in the 90-105 cm depth, with 8.2 Mg ha-1 (overall p<0.0001).

Unlike %C, there were fewer significant differences when comparing the surface mass carbon with the subsurface depths. The mass carbon content at 0-15 cm was different from the 90-105 cm depth at both MATTA (p=0.0313) and MTS (p=0.0161), while the 0-15 C content

75

Mass Carbon at 0-15 cm across sites

0

5

1015

20

25

30

35

4045

50

55


Site

Mas

s C

(Mg/

ha)

aa

bbc

bcdcd cd

cdcd

d

Figure 28a. Average mass C at 0-15 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.


05

1015202530354045505560


Site

Mas

s C

(Mg/

ha)

a

ab

bcbc

c cc

c cc

Figure 28b. Average mass C at 30-45 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

76


01020

304050607080

90100110


Site

Mas

s C

(Mg/

ha)

a

bbc

cd cddd d d

Figure 28c. Average mass C at 90-105 cm at each site. Different letters above treatment bars indicate differences at p≤0.05.

differed from both subsurface depths in RCK (p=0.0034 for 30-45 cm; p=0.0005 for 90-105 cm) and SWS (p=0.0098 for 30-45 cm; p=0.0020 for 90-105 cm). Due to the nature of the mass C calculation, these differences between mass C and %C can be attributed to the high bulk density of the subsoil samples. The subsoil layers have a much greater total soil mass than that found in the surface. Therefore, even though %C lowered significantly with depth, mass carbon did not because it was offset by the increasing mass per unit depth. The lack of site-specific wetland studies reporting mass C makes it difficult to assess the levels that were found in this study. However, Kern (1994) estimated that wetlands contain an average of 720 Mg C ha-1 in the contiguous United States. This average is somewhat skewed because it does not differentiate Histosols and bogs, which by definition, have very high organic matter contents. I would expect the average to be somewhat lower in Virginia, since Histosols do not have a dominant presence. Nevertheless, I suspect that all of our sites were well below average for natural wetland soils. 4.3 Soil Physical Properties 4.3.1 Texture Soils at MATTA, SWS, SCW, SB, and MTS contained high sand (>62%) contents in their surface layers. At the 30-45 and 90-105 cm depths, SCW had the highest sand content, with 83.6% and 85.9%, respectively (Table 16). MAN had the highest silt content at the surface, at 59.6%. At the 30-45 cm depth, MAN and BCK contained 54.5% and 51.6% silt, respectively; whereas BCK (42.6%), DC (41.2%), and CCW (37.2%) had the highest amounts of silt at the 90-

77

105 cm depth. Soils at CCW exhibited the highest clay content at all depths (overall p<0.0001 for all textures at all depths). Out of the seven sites constructed primarily by excavation and cutting (BCK, CCW, DC, MAN, MATTA, MTS, and RCK), three sites (CCW, MATTA, and RCK) showed significant differences in sand, silt, and clay contents with depth. In addition, MTS showed a difference in silt content, and DC varied in clay content. Meanwhile, two (SB and SCW) out of the three fill sites (SWS is the third) exhibited significant differences with depth for all particle size contents. Because the pure cut sites retained a portion of their original soil profile, they tended to demonstrate more pedogenic horizonation than the fill sites. However, sites requiring extensive cuts (e.g. BCK and DC) necessitated the removal of the entire B horizon, resulting in a soil profile that was generally less developed and lower in clay content. Thus, these soils had uniform textures, which were classified as silt loam at the 0-15 cm and 30-45 cm depths and loam at 90-105 cm.

Fill sites (SB, SCW, and SWS), for the most part, contained observable soil horizonation as well, but to a lesser degree. For example, SCW had more clay content at the surface (sandy loam), while coarser textured material (loamy sand) was found at both subsoil depths. Sandy Bottom (SB) also exhibited significant layers, as the soils contained more clay materials at the 30-45 cm depth. These subgrade soils were classified as sandy clay loam. However, SWS had the least developed soils of the fill sites, having homogenous textured soils (sand loam) throughout the soil column.

Due to the overall site development process and the relatively unweathered parent

materials utilized, the majority of sites had high sand contents (> 50%) at each measured depth. While not entirely impossible to create wetlands in this substrate, sandy textures definitely present more challenges than finer textures. Generally, sandy textures have lower CEC and water holding capacity, and higher porosity and permeability than fine-textured material (Stolt et al., 2000). As a result, maintaining appropriate hydrologic conditions could be difficult. Without persisting saturation to maintain anaerobic conditions, hydric soil formation and organic matter accumulation cannot occur. In addition, the inactive nature of sand could minimize the nutrient supply and retention causing lower long term site productivity. Furthermore, high sand content coupled with low organic matter could limit function, and therefore may not replace impacted wetlands from a functional perspective. For example, excessively sandy soils would not be ideal for nutrient sequestration (e.g. P) and processing functions. However, as noted earlier, the Virginia Coastal Plain contains numerous highly productive hydric soils that are coarse textured. It is also important to point out that bulk water holding and nutrient retention will increase with time if reconstructed soil systems in mitigation wetlands accumulate adequate amounts of reactive humus.

78

Table 16. Soil texture by depth across ten mitigation wetland study sites. Values within a column by depth class are significantly different (p ≤ 0.05) when followed by differing letters. Apparent irregularities in significant differences are due to unbalanced n values, which results in lack of power across certain pairwise contrasts.

Site % Sand % Silt % Clay Texture 0-15 cm BCK 37c 50b 13cd SIL CCW 22d 50b 28a SIL DC 48b 39c 13c L MAN 23d 60a 17bd SIL MATTA 69a 24f 7ef SL MTS 63a 31de 6f SL RCK 51b 31d 18b L SB 64a 23f 13c SL SCW 65a 24ef 11ce SL SWS 66a 19f 15bc SL 30-45 cm BCK 27de 52a 21bcd SIL CCW 21e 35bc 44a C DC 34d 42b 24bc L MAN 17e 54a 29b SICL MATTA 72ab 12fg 16de SL MTS 61bc 28cd 11e SL RCK 52c 21de 27b SCL SB 60bc 19ef 21cd SCL SCW 84a 6g 10e LS SWS 69b 18ef 13e SL 90-105 cm BCK 32c 43a 25b L CCW 26c 37a 37a CL DC 36c 41a 23b L MATTA 60b 18b 22bc SCL MTS 67b 16bc 17bcd SL RCK 68b 16bc 16bcd SL SB 66b 17b 17bcd SL SCW 86a 6c 8d LS SWS 67b 20b 13cd SL

Coarse textured soils appear to be prevalent in other created wetlands as well. Bishel-

Machung et al. (1996) studied 44 wetlands that were created between 1985 and 1992 and 20 reference wetlands in Pennsylvania. They found that sand contents were high (49%) at the 20 cm depth in created wetlands, while the natural wetlands had a higher percentage of clay (36%) at the same depth. An advanced state of weathering occurred in natural wetlands, as many of their sites contained argillic horizons. In contrast, created wetlands had a much more homogenous soil column, with little evidence of pedogenesis – a direct result of construction methods, which involves excavation of upland soils and the subsequent replacement of topsoil.

79

4.3.2. Bulk Density Sandy Bottom (SB) had the highest surface (0-15 cm) bulk density of 1.8 g cm-3, while

BCK had the lowest bulk density of 1.3 g cm-3. At the 30-45 cm depth, MTS, SCW, SB, and SWS had the highest bulk densities of 1.9 g cm-3, while RCK, MATTA, and CCW had the lowest bulk densities at 1.6 g cm-3 (see Figures 23a-c). Comparing the surface to the subsurface, there were significant differences at all sites except SB. As mentioned previously, root limiting bulk densities in soils range from 1.45 Mg m-3 for finer textures to 1.75 Mg m-3 for coarse loamy textures (Daniels & Whittecar, 2004). Based on these values, SB, DC, and MAN were considered to be root limiting at the surface, while CCW was very close to the root limiting threshold. Bulk density was at or above the root limiting threshold at all sites in the 30 to 45 cm subsurface (1.58 – 1.92 g cm-3), except for MATTA. This was clearly evident by the lack of observed roots beyond the A horizon at all described sites.

High bulk density found at the 10 VDOT sites is brought on by current construction

methods, which involve heavy machinery to excavate (or fill) and grade soils. Through these practices, the upper soil profile is removed, exposing soil horizons that have little to no structure. Fill sites also tend to have little soil structure due to their tendency of being a mixture of different soils from varying origination points. The original in-situ soil structure is then degraded and destroyed as the soil materials are cut, handled, stored and filled. This lack of structure reduces soil porosity, thereby increasing soil density when the materials are placed into fills.

In order to reduce soil density and associated strength and rooting resistance, all sites

studied here incorporated some soil tillage after grading. However, the tillage employed did not vary much from site to site, indicating that the observed differences across sites are related to other factors. All sites were disked on one occasion, typically to a depth of 15 cm. While a few sites received multiple passes (CCW, MTS, and SB), for the most part, it may have actually recompacted the soil surface. Organic matter could explain some of the differences observed across sites, since sites that did not receive any organic matter amendment (CCW, DC, MAN, and MTS) tended to have similar and higher bulk densities, whereas sites that were amended typically had bulk densities below the root-limiting threshold. Another factor could be the age of the site when the samples were taken. For example, SB was sampled one year after completion and exhibited the highest bulk density, while BCK, a four year-old site, had the lowest bulk density. Thus, based on my limited sampling, organic matter and time appear to be dominant factors in measured bulk density values.

Since the early to mid-1990s, Daniels and others have stressed to VDOT, via annual

research reports and in previously cited articles, that soil compaction is limiting the success of their created wetlands. In addition, other sources, such as the recently published USCOE/DEQ mitigation site development guidance (updated 2004), have recognized the impact that soil compaction has on created wetlands, and have recommended that ripping and disking activities produce an acceptable surface and subsoil bulk density. While clear direction has been offered, it appears that deep loosening of compacted mitigation site soils below the surface 0-15 cm has yet to be implemented as routine practice.

While soil disking occurred at each site, this activity was performed only once and to a

shallow depth. The resulting high bulk density values leads us to believe that created wetland

80

soils need to be disked and/or ripped more frequently and to a deeper depth. The timing of tillage and ripping is also important, since deep ripping will only be effective at drier times when large equipment can physically get onto a creation site and the subsoils are dry enough to shatter. Because deep (subsoil) ripping did not occur at any of the sites studied here, and soil carbon contents were low at each site, high bulk density and associated rooting limitations could persist for an extended period at these sites.

4.4 Summary

Mitigation site soils differed from each other due to a combination of factors, such as age

and soil reconstruction methods. As such, Table 17 summarizes soil reconstruction methods and provides an estimate of soil quality at each site based on soil properties that were considered to have a direct effect on overall quality. Table 17. Summary of site soil reconstruction methods and an estimate of soil quality at the time of sampling based on bulk density, pH, and soil organic carbon content. The overall rating indicates our assessment of the mitigation site soils to achieve and sustain hydric soil status as well as support forested growth.

Site

Age When

Sampled (Yrs)

Site Construction Method (m)

Returned Topsoil Depth (cm)

Tillage Type and

Depth (cm)

Bulk Density pH

Soil Organic Carbon Content

Overall Rating

BCK 4 Cut: 1.07 15 Disked: 5-8

Adequate: Root limiting at depth

Adequate: Close to estimate found in natural wetlands (4-5)

Limiting, less than 2% Adequate

CCW 4 Cut: 0.6 - 0.9 2 - 8 Disked: 15




DC 2 Cut: 0.6 - 0.9 15 Disked: 15

Limiting: Root limiting at surface


Limiting, less than 2% Limiting

MAN 3 Cut: 0.56 Unknown depth

Disked: unknown depth


Limiting: Unsuitable pH to promote hydric soil formation


MATTA 1 Cut: 0.6 - 1.2 30 Disked: 15

Good: Root penetrable soil

Limiting: Unsuitable pH to promote hydric soil formation, sulfidic materials with depth


MTS 4 Cut: 0.8 - 0.9 15

Ripped and disked: 15




81

Table 17 (cont.).

Site

Age When

Sampled (Yrs)

Site Construction Method (m)

Topsoil Depth (cm)

Tillage Type and

Depth (cm)

Bulk Density pH

Soil Organic Carbon Content

Overall Rating

RCK 3 Cut: 0.3 - 0.9 30 Disked: 15




SB 1 Fill 15 Disked: 20




SCW 4 Fill 10 Disked: 15



Good: more than 2% Good

SWS 2 Fill Unknown depth

Disked: unknown depth


Limiting: Unsuitable pH to promote hydric soil formation, evidence of exposed sulfidic materials in some areas

Good: more than 2% Good

82

5. CONCLUSIONS

The mitigation wetlands studied differed from each other with respect to soil chemical and physical properties. However, overall, created wetland soils are plagued by low C and N content and high pH, coarser particle size, and bulk density when compared to documented properties of natural hydric soils. These adverse characteristics are due to construction methods and lack of time for organic matter to accumulate.

Organic matter amendments were applied at the majority of sites studied (6 of 10).

However, due to the low levels of % soil C, mass C, and total N found at most sites, it appears that the rates at which they were applied (target 4% OM) were insufficient to generate soil organic matter levels sufficient to sustain essential hydric soil functions. In order to achieve viable created wetlands, it seems that higher initial amendment rates, possibly 5% or more, are necessary. With the added organic matter, created wetlands should react favorably, both physically and chemically. With time and appropriate hydrologic conditions, organic matter should accumulate with the end-result including, but not limited to, overall horizon development, appropriate hydric soil/biogeochemical conditions, increased water holding capacity and nutrient supply, and perhaps most importantly, reduced bulk density.

The pH at the soil surface at each site was moderately acid to near neutral due to the

routine application of lime amendments. As a result, redoximorphic feature formation and organic matter accumulation could be delayed in created wetlands. While high soil pH is a common trait in created wetlands, strongly acidic soils (pH< 4) can also be found in sites containing sulfidic materials. Great care should be taken to avoid exposure and oxidation of sulfidic materials since the resulting conditions are detrimental to the environment.

Coarse textures are also prevalent in created wetlands. Due to the porous and inactive

nature of sand, maintaining appropriate hydrologic conditions and providing sufficient nutrients for plant growth could prove to be difficult. In addition, sites containing higher sand contents coupled with low organic matter would be expected to have limited function, and therefore may not replace impacted wetlands from a functional perspective.

Current practices leave soils in a very compacted state, which leads to root limiting bulk

densities. This was clearly evident by the lack of roots found in the subsurface soils at all ten sites. Incorporating annual (site conditions permitting, for at least the first two years) topsoil disking and subsoil ripping to a depth of 45 – 60 cm as part of the construction method should greatly improve conditions. Not only will this allow vegetation establishment and rooting to be more successful, but other soil functions, such as hydraulic conductivity will improve as well.

The soil color patterns observed in these soils, for the most part, reflect their former states

and as such, are primarily relicts of pre-existing soil conditions. It will probably take years of saturation and organic matter accumulation to reduce overall soil matrix chroma. While a total of 35 observed soil locations at eight sites did meet the depleted matrix (F3) NRCS indicator, it is most likely because excavation brought those depleted horizons closer to the surface, not because there was a change in the hydrologic regime. Also, Fe/Mn concentrations and depletions were found at all of the sites, but it is difficult to say with certainty whether they were

83

relict or contemporary. Pore linings, on the other hand, more likely reflect the current soil redox state. For this reason, they may be a better indicator to rely upon to determine if redox processes are active at a given site. As such, nine out of ten sites (SB was the exception) indicated active redox conditions in at least one sampled pedon. Though overall, I found that 45% of the observed soil locations met a Hydric Soil Indicator.

Created wetlands presumably need to meet the same jurisdictional criteria as natural wetlands for permit liability release, and should also replace important wetland functions as well. However, natural forested wetland systems in Virginia have had thousands of years to develop. In contrast, monitoring of created wetlands typically occurs for only five to ten years after creation. With current technologies, it is not reasonable to expect that created wetland soils can approach the same level of form and function found in natural wetlands within this time frame. More research is necessary to understand the intricacies of hydric soil development processes, which will result in improved site design and construction methods. In the interim, it is highly recommended that organic amendments be applied at a rate of 5% or more and that ripping/chisel-plowing to a depth of 45 – 60 cm be incorporated during soil reconstruction to increase chances of overall created wetland success.

84

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91

APPENDICES Appendix A. Scientific names for all recorded plants. Scientific Name Common Name Acer negundo L. boxelder Acer rubrum L. red maple Agrostis stolonifera L. creeping bentgrass Alisma plantago-aquatica L. mudplantain Alisma subcordatum Raf. American water plantain Alnus serrulata (Ait.) Willd. tag alder Betula nigra L. river birch Carex crinita Lam. fringed sedge Carex lupulina Muhl. ex Willd. hop sedge Carex lurida Wahlenb. shallow sedge Carpinus caroliniana Walt. American hornbeam Cephalanthus occidentalis L. buttonbush Cornus amomum P. Mill. silky dogwood Decodon vertcillatus water loosestrife Digitaria Haller crabgrass Fraxinus pennsylvanica Marsh. green ash Hibiscus moscheutos L. crimsoneyed rosemallow Ilex decidua Walt. possumhaw Ilex verticillata (L.) Gray winterberry Iris virginica L. Virginia Iris Juncus effusus L. soft rush Lobelia cardinalis L. cardinal flower Lolium perenne L. perennial ryegrass Ludwigia alternifolia L. seedbox Ludwigia repens J.R. Forst. creeping primrose-willow Nyssa aquatica L. water tupelo Peltandra virginica (L.) Schott arrow arum Photinia pyrifolia (Lam.) Robertson & Phipps red chokeberry Phragmites australis (Cav.) Trin. ex Steud. common reed Pinus serotina Michx. pond pine Platanus occidentalis L. American sycamore Polygonum hydropiperoides Michx. swamp smartweed Pontederia cordata L. pickerelweed Quercus bicolor Willd. swamp white oak Quercus lyrata Walt. overcup oak Quercus nigra L. water oak Quercus pagoda Raf. cherrybark oak Quercus palustris Muenchh. pin oak Quercus phellos L. willow oak Rorippa nasturtium-aquaticum (L.) Hayek watercress

92

Scientific Name Common Name Rosa palustris Marsh. swamp rose Sagittaria latifolia Willd. duck potato Salix nigra Marsh. black willow Sambucus nigra L. ssp. Canadensis (L.) R. Bolli elderberry Saururus cernuus L. lizard's tail Scirpus cyperinus (L.) Kunth woolgrass Sparganium americanum Nutt. American bur-reed Stuckenia pectinatus (L.) Boerner sago pondweed Taxodium distichum (L.) L.C. Rich. bald cypress Trifolium L. clover Typha latifolia L. broadleaf cattail Ulmus americana L. American elm Vaccinium corymbosum L. highbush blueberry Viburnum dentatum L. southern arrowwood

93

Appendix B. Redoximorphic features: quantity, size, and contrast. Code Class Description Quantity F Few <2% C Common 2-20% M Many >20% Size 1 Fine <5 mm 2 Medium 5-15 mm 3 Coarse >15 mm Contrast F Faint Evident only on close inspection. Faint features have the

same hue as the matrix, but differ from the matrix color by ≤ 2 in value and ≤ 1 in chroma.

D Distinct Contrasts moderately with the matrix color. Features are distinct when they are the same hue as the matrix, but differ between > 2 to < 4 in value and < 4 in chroma or < 4 in value and >1 to < 4 in chroma. Distinct features can also differ by 2.5 hue units when the value is ≤ 2 in value and ≤ 1 in chroma.

P Prominent Contrasts strongly with the matrix color. Features are prominent when they are of the same hue as the matrix color, but differ by ≥ 4 in value or chroma; or when the hue differs 2.5 units from the matrix and has > 2 in value or > 1 in chroma; or when the hue differs by at least 5 hue units.

94

Appendix C. Pedon descriptions for BCK. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1 Ap 0-12 10YR 4/4

5YR 3/4 C1P Pore linings 3F SIL 3COSBK

5YR 2.5/1 C2P Pore linings

2.5Y 5/2 C3P In matrix

5Y 4/1 F3P In matrix

2BA 12-38 7.5YR 4/6

7.5YR 2.5/1 C2P Mn nodules -- SIL 3VFSBK

5Y 5/3 C1P Pore linings

2.5Y 6/1 F2P

Along pores

2Bt 38-102

2.5YR 4/6

10YR 6/8 F1D

Fe concretions -- L 3COSBK

10YR 5/6

2.5YR 2.5/1 F1P Mn masses

N 7/0 C1P Along pores

2Btg 102-141 5Y 7/1

10YR 5/8 M2P Fe masses -- L 2COSBK

2 Ap 0-21 10YR 4/4

10R 2.5/1 C2P Mn masses

3VF, 3F SIL 3MGR

10YR 5/4 C2F Fe masses

5YR 5/8 F1P Pore linings

2Bt 21-78 10YR 5/8

7.5YR 3/2 C1P Mn masses -- L 2MSBK


7.5YR 4/6 C1P Pore linings

3 Ap 0-14 7.5YR 4/4

5YR 3/4 C1D Pore linings 2M SIL 3VCGR

5Y 5/2 C3P In matrix

2BA 14-73 7.5YR 4/6

5YR 5/8 C1P Pore linings -- SIL 1FSBK


2Cg 73-150

10YR 5/1

7.5YR 4/6 M1P Pore linings -- SIL 0MA

2.5Y 7/2 F1D Pore linings

95


Matrix Color

Redox Color

Redox Description


4 Ap 0-23 10YR 4/4

5YR 4/4 C2P Fe masses 3VF SIL 3MSBK

N 2.5/0 F1P Mn masses


5Y 6/2 C1P Along pores

2BA 23-55 7.5YR 4/4

5YR 4/6 C2P Fe masses -- SIL 3COSBK

5Y 5/3 C2P Pore linings 5Y 6/3 C2P Pore linings

2Bt 55-72 7.5YR 5/8

7.5YR 4/4 C2P Fe masses -- SIL 3COSBK

2.5Y 6/6 F1P Fe masses

N 2.5/0 C1P Pore linings


2Ctg 72-150+ N 6/0

10YR 5/8 M3P Pore linings -- CL 0MA

Water Table @ 91 cm


5 Ap 0-15 2.5YR 2.5/1

2.5YR 3/4 C1P Pore linings 3VF L 3COGR

10YR 4/4

2BA 15-42 2.5Y 5/3

2.5YR 2.5/3 C3P Fe masses -- SIL 3MSBK


10YR 7/1 F1P In matrix

2Bt 42-94 5YR 5/6

2.5YR 4/6 C3D Pore linings -- CL 3COSBK

2.5Y 4/2 F2P In matrix


2.5Y 6/6 C2P Pore linings

2BC 94-117

10YR 4/6

10YR 5/6 C3D Fe masses -- SL 1MSBK

10R 3/3 C2P Fe masses

N 2.5/0 C2P Mn nodules

2.5Y 6/1 C2P

Along pores

2C 117-137

10YR 5/6 -- -- -- -- SL 0MA

extremely gravelly

96


Matrix Color

Redox Color

Redox Description


6 Ap 0-14 7.5YR 2/1

7.5YR 4/3 F2D Fe masses 3VF SL 3COGR


2C1 14-28 5YR 4/6

2.5Y 5/2 F3P In matrix -- SIL 0MA

2.5YR 4/6 F2D Pore linings

5BG 5/1 C2P

Along pores

N 2.5/0 C1P

Along pores

2C2 28-73 2.5YR 4/8

10YR 4/1 C2P In matrix -- SICL 0MA


7.5YR 2.5/1 C1P Pore linings

2Cg 73-97 7.5YR 4/6

2.5YR 4/8 C2P Fe masses -- SICL 0MA

10Y 7/1

5YR 3/3 C3P Pore linings

5YR 2.5/1 F1P Pore linings

97

Appendix D. Pedon descriptions for CCW. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998). Location Horizon

Depth (cm)

Matrix Color

Redox Color

Redox Description


1* Apg 0-2 10YR 4/0

7.5YR 6/8 C1P

Fe masses

3F, 3M CL 1FGR

7.5YR 5/8 C1P

Fe masses

7.5YR 6/8 C1P

Pore linings

2Btg 2-41 7.5YR 6/0

7.5YR 6/8 M1P

Fe masses

2F, 2M CL

3COABK, PL

7.5YR 7/0 M1F

In matrix

2BC1 41-64 7.5YR 6/8

7.5YR 6/0 M2P

In matrix -- SL 0MA

2BCg1 64-91 7.5YR 6/0

7.5YR 6/8 C1P

Fe masses -- SIL 0MA

2BCg2 91-154

5YR 7/1 5YR 6/8 M2P

Fe masses -- L 0MA

2* Apg 0-2 10YR 4/2

7.5YR 5/6 F1P

Fe masses

3F, 3M CL 1FGR

2Btg 2-71 7.5YR 6/0

7.5YR 7/8 C2P

Fe masses

2F, 2M C 3COABK

7.5YR7/0 C1F In matrix

7.5YR 5/0 C2F

Along pores

7.5YR 7/6 F1P

Fe masses

2BCg 71-124

10YR 7/1

7.5YR 6/8 C2P

Fe masses -- SCL 0MA

10YR 6/1 M1F In matrix

2BC2 124-147

7.5YR 6/8 10YR 7/1 M2P

In matrix -- CL 0MA

10YR 6/1 M2P In matrix

3* Apg 0-2 7.5YR 4/0 -- -- --

3F, 3M CL 1FGR

2Btg1 2-36 7.5YR 5/0

7.5YR 6/8 M1P

Fe masses 1F CL 3COABK

5YR 4/6 F2P Fe masses

7.5YR 7/0 C2F

In matrix

7.5YR 4/1 C2F

In matrix

2Btg2 36-76 7.5YR 5/0

7.5YR 6/8 F1P

Fe masses -- CL 3COABK

7.5YR 6/0 C2F

In matrix

7.5YR 4/1 M2F

In matrix

2BC 76-140

7.5YR 6/6

7.5YR 6/0 M2P

In matrix -- SIL 0MA

98


Matrix Color

Redox Color

Redox Description


4* Apg 0-12 10YR 5/2

7.5YR 5/8 F1P

Pore linings

3F, 2M SIL 1FGR

2Btg 12-86 7.5YR 5/0

7.5YR 6/8 C1P

Fe masses 1F C 2PL

Structure changes to 3COABK with depth

5YR 5/8 C2P Fe masses


7.5YR 7/8 F1P

Fe masses

7.5YR 7/0 M2F

In matrix

2BC 86-127

7.5YR 7/0

7.5YR 6/8 M2P

Fe masses -- L 0MA

5YR 5/8 M3P Fe masses

5* Btg1 0-41 7.5YR 5/0

7.5YR 5/8 C1P

Pore linings

3F, 2M C 1MABK



Btg2 41-104

7.5YR 5/0

7.5YR 6/8 C2P

Fe masses C 1MABK

WT @ 90 cm

10YR 7/1 C2D In matrix --

BCg 104-152

10YR 6/1

7.5YR 6/8 M2P

Fe masses SIC 0MA

7.5YR 7/0 F1D

In matrix --

6 A 0-10 10YR 5/3

7.5YR 4/6 C1P

Pore linings

3F, 2M SIL 1MSBK

Bt 10-38 10YR 5/4

7.5YR 5/8 M1P

Fe masses -- CL 1MSBK

Structure changes to 1MPL with depth

7.5YR 4/6 C1P

Pore linings


Btg1 38-66 7.5YR 4/0 5YR 5/8 C1P

Fe masses -- C 2MABK

Btg2 66-107

10YR 7/2

7.5YR 6/8 C2P

Fe masses -- CL 2MABK

10YR 6/1 F1F In matrix

BCg1 107-127

7.5YR 6/0

7.5YR 6/8 M2P

Fe masses -- SIC 0MA

7.5YR 5/0 M2F

In matrix

BCg2 127-140

7.5YR 6/0

7.5YR 6/8 C1P

Fe masses -- SICL 0MA

BCg3 140-165

7.5YR 6/0

7.5YR 6/8 M1P

Fe masses -- CL 0MA

WT @ 163 cm

99


Matrix Color

Redox Color

Redox Description


7* Apg 0-8 10YR 4/2

10YR 6/6 F1P

Fe masses

3F, 3M SIL 1FGR

2Btg1 8-36 10YR 5/1

7.5YR 6/8 C1P

Fe masses

2F, 2M SIC 2MABK

2.5YR 4/6 C1P

Fe masses


7.5YR 6/8 F1P

Pore linings

10YR 6/6 F2P

Fe nodules

2Btg2 36-117

10YR 6/1

7.5YR 6/8 C1P


WT @ 117 cm

10YR 5/1 M1F

In matrix

2BCg 117-157

10YR 6/1

7.5YR 6/8 M1P

Fe masses -- SIC 0MA

8 ABtg 0-8 10YR 4/2

10YR 6/8 F1P

Fe masses

3F, 3M CL 1FGR

2Btg 8-30 10YR 7/1

10YR 6/8 M2P

Fe masses 1F SIC 2MABK


10YR 5/1 M1F

In matrix

2Bt 30-64 7.5YR 6/8

7.5YR 6/0 M2P

In matrix -- SIC 2MABK

2BCg1 64-122

10YR 7/1

7.5YR 5/8 C1P

Fe masses -- CL 2MABK

7.5YR 6/8 C2P

Fe masses

10YR 5/1 C2F

In matrix

2BCg2 122-152

7.5YR 6/0

7.5YR 5/8 M1P

Fe masses -- L 0MA

9 Apg 0-10 10YR 5/2 -- -- --

3F, 3M SIL 1FGR

2Btg1 10-28 10YR 5/1

10YR 5/6 M2P

Fe masses

2F, 1M SIC 2MABK

7.5YR 5/8 M2P

Fe masses

10YR 6/8 F1P

Pore linings

10YR 7/1 C2F In matrix

2Btg2 28-53 7.5YR 6/0

7.5YR 6/8 M2P


WT @ 53 cm

7.5YR 7/8 M2P

Fe masses

7.5YR 7/0 C1F In matrix

2BCg 53-152

7.5YR 7/0

7.5YR 7/8 M2P

Fe masses -- C 0MA

100


Matrix Color

Redox Color

Redox Description


10* Apg 0-8 10YR 4/2 -- -- --

3F, 3M SIL 1FGR

2F, 2M pieces of organic matter (bark, twigs, etc.)

2Btg1 8-53 10YR 5/1

7.5YR 6/8 C1P

Fe masses 2F SIC 2MABK

10YR 6/1

7.5YR 5/8 C1P

Pore linings

10YR 6/6 C1P

Fe masses

2Btg2 53-114

7.5YR 6/0

7.5YR 6/8 M1P

Fe masses -- SIC 2MABK

5YR 5/8 M2P Fe masses

2Btg3 114-140

7.5YR 7/0

7.5YR 6/8 C1P

Fe masses -- SIC 2MABK

7.5YR 5/0 F2F In matrix

*Met the depleted matrix (F3) Hydric Soil Indicator

101

Appendix E. Pedon descriptions for DC. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998). Location Horizon

Depth (cm)

Matrix Color

Redox Color

Redox Description


1 Ap 0-8 10YR 4/3 -- -- -- 2F SL 1FGR

2AB 8-25 10YR 6/4

7.5YR 4/6 M2P

Fe masses 2F SL 1FPL

7.5YR 4/6 F1P

Pore linings

7.5YR 6/8 F1P

Pore linings

2Btg1 25-76 10YR 7/1

7.5YR 4/6 C1P

Fe masses -- L 3COABK

7.5YR 6/8 C1P

Fe masses

2Btg2 76-160

7.5YR 7/0

7.5YR 5/8 M2P

Fe masses -- CL 3COABK

7/1 5B 7.5YR 3/0 C1P

Mn nodules

2 Ap 0-20 7.5YR 4/6 -- -- -- -- SIL 1FSBK

2BC1 20-69 7.5YR 5/4

10YR 7/4 C1D

Fe masses -- SICL 2FSBK

7.5YR 2/0 C1P

Mn nodules

2BC2 69-142

7.5YR 4/6

7.5YR 7/0 M1P In matrix -- SICL 0MA

7.5YR 2/0 C1P

Mn nodules --

2BC3 142-168

7.5YR 5/6

7.5YR 6/0 M2P In matrix -- L 0MA

3* Ap 0-10 10YR 5/4 -- -- --

2F, 2M L 1FGR

2BCg 10-79 10YR 7/2

10YR 6/8 C1P

Fe masses -- SIL 1FSBK

10YR 5/6 C2P

Fe masses

2BC 79-155

7.5YR 5/8

7.5YR 6/8 C1F

Fe masses -- SIL 0MA


4 Ap 0-10 10YR 4/4 -- -- --

2F, 2M L 1FPL

2Bx 10-36 10YR 6/4

7.5YR 6/8 C1P

Fe masses -- L 2MPL

10YR 7/1 C2D In matrix

2Bt 36-109

10YR 7/3

7.5YR 6/8 M2P


7.5YR 3/0 C2P

Mn nodules


2Btg 109-157

7.5YR 7/0

7.5YR 6/8 M2P

Fe masses -- SIL 2MSBK

7.5YR 3/0 C2P

Mn nodules

102


Matrix Color

Redox Color

Redox Description


6 Ap 0-15 7.5YR 4/4 -- -- --

1F, 1M SL 1FGR

2Bt 15-33 7.5YR 5/6

7.5YR 6/8 C1D

Fe masses -- L 2FPL

7.5YR 7/0 M2P In matrix

2Btg 33-53 7.5YR 6/0

7.5YR 5/8 M1P

Fe masses -- L 1FSBK

7.5YR 3/2 C1D

Mn nodules

2BC1 53-74 7.5YR 5/6

7.5YR 5/8 C1D

Fe masses -- L 0MA

7.5YR 3/2 C1P

Mn nodules


2BC2 74-114

10YR 6/3

7.5YR 5/8 C1P

Fe masses -- SL 0MA

2BC3 114-157

7.5YR 5/4

10YR 6/3 M2D

Fe masses -- SL 0MA

7.5YR 7/0 C1P In matrix

7* Ap 0-3 7.5YR 5/4

7.5YR 6/8 C1P

Pore linings

1F, 1M CL 1FSBK/PL

2Btg1 3-25 10YR 7/1

10YR 4/6 C1P

Fe masses -- CL 1MPL

7.5YR 6/8 C1P

Fe masses

2Btg2 25-69 7.5YR 6/0

7.5YR 6/8 M2P

Fe masses -- CL 1FSBK

7.5YR 3/2 C1D

Mn nodules

2BC 69-152

7.5YR 6/8

7.5YR 6/0 M2P In matrix -- SIL 0MA

7.5YR 3/0 C1P

Mn nodules

8* Ap 0-25 7.5YR 4/4 -- -- -- 2F L 1FSBK

2BCg 25-109

10YR 7/2

7.5YR 5/8 C2P

Fe masses -- SL 0MA

7.5YR 4/6 M2P

Fe masses

2BC 109-127

10YR 7/4

7.5YR 5/4 M2D

Fe masses -- SL 0MA

7.5YR 6/8 C1P

Fe masses

2BC'g 127-157

10YR 7/2

7.5YR 6/8 C3P

Fe masses -- SL 0MA

WT @ 152 cm

7.5YR 5/6 C2P

Fe masses

9* Ap 0-5 7.5YR 5/4

7.5YR 6/8 M1P

Pore linings

2F, 2M L 1FGR

2Btg1 5-20 10YR 5/1

7.5YR 5/8 C1P

Fe masses -- L 2FPL

2Btg2 20-61 7.5YR 6/0

7.5YR 6/8 C1P


7.5YR 3/0 C1D

Mn nodules

2BCg 61-152

7.5YR 5/0

7.5YR 5/8 M3P

Fe masses -- L 0MA

7.5YR 3/0 C1F

Mn nodules

103


Matrix Color

Redox Color

Redox Description


10 Ap 0-10 7.5YR 4/6

7.5YR 5/8 C1D

Pore linings

2F, 1C L 1FPL

Ag 10-15 2.5Y 4/2

7.5YR 5/8 C2P


1F, 1M organic matter pieces

2BC 15-71 10YR 6/3

7.5YR 4/6 M2P

Fe masses -- SL 0MA

7.5YR 6/8 C1P

Fe masses

2BCg1 71-104

7.5YR 6/0

7.5YR 6/8 C1P

Fe masses -- SL 0MA

WT @ 102 cm

7.5YR 7/0 C1F In matrix

2BCg2 104-127 6/1 5B

2.5YR 4/6 M3P

Fe masses -- SL 0MA

2Cg 127-160 6/1 5B

7.5YR 7/0 F1P In matrix -- SL 0MA


104

Appendix F. Pedon descriptions for MAN. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1† Ap 0-23 7.5YR 5/4

7.5YR 6/8 C1P

Pore linings

2F, 1M SIL 2MPL

2C 23-30 2.5YR 5/8 -- -- -- -- L 0MA

R 30+ -- -- -- -- -- -- -- red shale bedrock

2 Ap 0-20 7.5YR 5/4

7.5 YR 5/8 F1P

Fe masses

2F, 1M L 1MPL

2C 20-23 2.5YR 4/6 -- -- -- -- L 0MA


3 Ap 0-13 7.5YR 5/6 -- -- --

1F, 1M CL 1FPL

2C 13-23 5YR 4/6 7.5YR 6/0 M2P

In matrix -- CL 0MA


4† Ap 0-13 7.5YR 5/4

5YR 5/4 C2D

Fe masses

2F, 2M SIL 1MSBK

2Bt 13-67 5YR 5/8 5YR 7/2 F2P

In matrix -- SIL 2MSBK


5 Ap 0-38 7.5YR 4/4

10YR 4/6 C2P

Fe masses

3F, 2M SIL 1FPL WT @ 8 cm

7.5YR 5/6 C1D

Pore linings

2C 38-84 7.5YR 7/8

7.5YR 8/0 M2P

In matrix -- SICL 0MA


6 Ap 0-23 7.5YR 4/4

7.5YR 6/8 F1P

Pore linings

2F, 1F L 2MPL

7.5YR 2/0 F2P

Mn nodules

2BC1 23-61 7.5YR 5/8

7.5YR 6/4 F2P


2BC2 61-94 7.5YR 5/8

7.5YR 6/8 C2F

Fe masses -- SIC 1MSBK

7.5YR 4/0 F2P

Mn nodules

5YR 6/1 M2P

In matrix


7 Ap 0-20 5YR 5/8 -- -- -- 2F SIL 1FSBK


105


Matrix Color

Redox Color

Redox Description


8 Ap 0-10 5YR 5/6 7.5YR 6/8 F1P

Pore linings

2F, 2M SIL 1FSBK

2BC1 10-36 5YR 5/8 7.5YR 6/8 C1D

Fe masses -- SICL 1MPL

7.5YR 2/0 C1P

Mn nodules

5YR 7/2 C1P

In matrix

2BC2 36-58 2.5YR 4/8

7.5YR 7/0 C2P

In matrix -- CL 1MPL

10YR 7/3 F1P

Fe masses


9 Ap 0-10 5YR 5/8 -- -- -- 1F SIL 1MSBK

2BC 10-20 5YR 4/6 5YR 7/2 C2P

Fe masses -- SIL 2MPL


10 Ap 0-13 5YR 5/6 7.5YR 6/8 C1P

Pore linings

2F, 2M, 1C SIL 1MSBK

5YR 5/8 C2P

Fe masses

10YR 8/2 F1P

In matrix

10YR 2/1 F1PP

Mn nodules

2Bt 13-23 10YR 6/6 -- -- -- -- SIL 2FPL

2C 23-36 2.5YR 4/6 -- -- -- -- L 0MA


† Met the red parent material (TF2) Test Hydric Soil Indicator

106

Appendix G. Pedon descriptions for MATTA. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1 Ap 0-30 10YR 4/3 -- -- --

2F, 2M SL 1FGR

many fine organic material (twigs, leaves, etc) present

10YR 5/8 roots extend to 10 cm

2BC 30-46 7.5YR 6/8

7.5YR 6/0 C2P

In matrix -- LS 0SGR 40% gravel

2Cg1 46-51 7.5YR 6/0

7.5YR 6/8 C2P


many mica flakes

2C 51-157

7.5YR 3/0 -- -- -- -- SL 0MA

many mica flakes

WT @ 137 cm

2 Apg 0-20 10YR 5/3

7.5YR 6/8 F1P

Fe masses 1F SL

1FGR/ SBK

common fine organic material (twigs, leaves, etc) present

7.5YR 5/0 2% gravel

2C1 20-41 7.5YR 6/8 -- -- -- -- S 0SGR

7.5YR 7/4 R 41+ cobble layer

3 Ap 0-18 10YR 4/3

7.5YR 5/8 C1P

Pore linings

2F, 2M SL 0MA


2% gravel

BC1 18-34 10YR 7/4 -- -- -- -- S 0SGR

5-50% rounded quartz gravel with depth

BC2 34-43 5YR 5/6 -- -- -- -- LS 0SGR

40% rounded quartz gravel

4 Ap 0-32 10YR 4/3 -- -- --

3F, 3M SL 0MA


7.5YR 6/8

2Cg 32-80 10YR 4/1 -- -- -- -- SCL 0MA

auger hole caved in below 80 cm; WT @ 80 cm

5* Ap 0-16 10YR 4/3

5YR 5/8 F1P

Pore linings

3F, 3M SL 0MA


2BC 16-19 7.5YR 6/8 -- -- -- -- CL 0MA

40% quartz gravel

2Cg 19-170

2.5Y 4/0 -- -- -- -- SCL 0MA

many mica flakes

107


Matrix Color

Redox Color

Redox Description


6* Ap 0-17 10YR 4/3 -- -- --

2F, 2M SL 0MA


7.5YR 5/8

water flowing through gravel layer at 17 cm

2BC 17-23 7.5YR 6/8 -- -- -- -- SCL 0MA

50% quartz gravel

2Cg1 23-145

2.5Y 4/0 -- -- -- -- SL 0MA

2Cg2 145-175

2.5Y 4/0 -- -- -- -- SL 0MA

common medium white shell fragments

7* Ap 0-14 10YR 4/3 -- -- --

3F, 3M SL 0MA


roots extend to 10 cm

2Cg1 14-130

2.5Y 4/0 -- -- -- -- SCL 0MA

many mica flakes

2Cg2 130-165

2.5Y 4/0 -- -- -- -- SL 0MA

many mica flakes


8* Ap 0-16 10YR 4/3

7.5YR 5/8 C1P

Pore linings

2F, 2M SL 0MA


2Cg1 16-125

2.5Y 4/0 -- -- -- -- SCL 0MA

many mica flakes

2Cg2 125-165

2.5Y 4/0 -- -- -- -- SCL 0MA


9 Ap 0-22 10YR 4/3

7.5YR 5/8 F1P

Pore linings

3F, 3M SL 0MA


2Cg 22-26 10YR 6/2 -- -- -- -- S 0SGR

2C 26-30 10YR 7/4 -- -- -- -- S 0SGR

2C'g 30-170

2.5Y 4/0 -- -- -- -- SCL 0MA

many mica flakes

6/1 10BG

thin layer at upper boundary

108


Matrix Color

Redox Color

Redox Description


10 Ap 0-20 10YR 4/3

7.5YR 5/8 F1P

Pore linings

2F, 2M SL 0MA


2Cg 20-40 2.5Y 7/0 -- -- -- -- S 0SGR

auger hole caved in at 40+ cm; WT @ 20 cm


109

Appendix H. Pedon descriptions for MTS. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1‡ Apg 0-18 5Y 4/2 10YR 6/8 F3P

Pore linings 3M LS

3VCGR

7.5YR 5/6 M1P Pore linings

5GY 7/1 C3P

In matrix

10YR 6/1 F3P

In matrix

2C1 18-80 10YR 6/8

7.5YR 5/8 F3D

Fe masses -- LS 0SGR WT @ 30 cm

2.5Y 6/4 C3P Fe masses

N 8/0 C1P Along pores

2C2 80-98 2.5Y 6/4

7.5YR 6/8 F1P

Pore linings -- LS 0SGR

2.5Y 7/1 C2D

In matrix

2Cg 98-150+ N 7/0

7.5YR 5/8 C3P

Fe masses -- SL 0MA Sand lenses

2‡ Apg 0-21 10YR 4/2

7.5YR 4/6 M2D

Pore linings

2VF, 2F LS

3COGR WT @ 15 cm


2C1 21-90 2.5Y 7/3

10YR 5/8 C3D

Fe masses -- LS 0SGR

10YR 5/6

2.5Y 2.5/1 F1P Mn masses

2C2 90-150+

2.5Y 5/4

7.5YR 5/8 F3P

Fe masses -- S 0SGR

3* Apg 0-32 2.5Y 4/2

7.5YR 5/6 M1P

Pore linings

3VF, 3F SL

3COGR Roots to 10 cm

10YR 5/2 F2D

In matrix WT @ 15 cm

2BCg 32-60 10YR 5/1

10YR 5/4 F2D

Pore linings -- SL

2MSBK



2Cg1 60-88 10YR 6/1

7.5YR 5/8 F1P



2.5Y 6/4 M3P Pore linings

2Cg2 88-150+

2.5Y 6/2

2.5Y 5/2 F2F

In matrix -- S 0SGR

110


Matrix Color

Redox Color

Redox Description


4 Ap 0-22 2.5Y 4/3

2.5Y 6/6 F1D

Pore linings 3VF SL 3MGR Roots to 10 cm

7.5YR 6/8 F1P Pore linings

2BA 22-60 2.5Y 6/4

2.5Y 6/3 F3F

Pore linings -- SL 2FSBK


2Bw 60-103 2.5Y 6/3

2.5YR 2.5/1 F1P

Pore linings -- SL

2MSBK

10YR 6/8



2.5Y 8/3 C2F Fe masses

2BCtg 103-150+

2.5Y 7/1

7.5YR 5/6 C3P Fe masses -- SCL 0MA WT @ 107 cm



5 Ap 0-21 2.5Y 5/3

7.5YR 5/6 C1P

Pore linings

3VF, 3F SIL


2Bt1 21-39 2.5Y 6/6 5Y 5/8 C1P

Pore linings -- L

3COSBK

7.5YR 2.5/3 F2P Pore linings



2Bt2 39-102 7.5YR 5/8

5YR 5/8 F1F

Pore linings -- SCL

3COSBK WT @ 46 cm


2Cg1 102-129

10YR 7/1

10YR 6/8 C2P

Pore linings -- SL 0MA

2Cg2 129-150+

10YR 8/2 -- -- -- -- SL 0SGR

6* Apg1 0-17 2.5Y 5/2

7.5YR 4/6 C2P

Pore linings

2VF, 2F SL 3FSBK


Apg2 17-39 7.5YR 4/1

5YR 3/4 C3P

Pore linings 2VF SL

3MSBK

Roots in upper 3 cm

2BCg 39-50 2.5Y 6/2

7.5YR 3/4 C2P

Pore linings -- SIL

3MSBK


2BCtg1 50-90 2.5Y 6/2

7.5YR 5/8 M3P

Pore linings -- SICL 0MA


2BCtg2 90-150+

2.5Y 6/2

2.5YR 3/2 C2P

Fe nodules -- CL

3COSBK



111


Matrix Color

Redox Color

Redox Description


7 Ap 0-27 2.5Y 4/3

10YR 5/6 C2P

Pore linings 2F SL


2BC 27-66 2.5Y 6/6

10YR 6/8 F3P Fe masses -- LS 0SGR


2BCg 66-85 2.5Y 4/1 5Y 5/4 F2P Fe masses -- SL 3MGR


2BCtg1 85-133 7.5YR 5/8

2.5Y 5/6 F3P Fe masses -- SCL 0MA

5Y 6/2 5YR 5/8 F1P Pore linings

7.5YR 4/1 F2P In matrix

2BCtg2 133-150+

10YR 6/1

5YR 3/4 F1P Fe masses -- SL

3COSBK

7.5YR 4/6 C3P Fe masses

5YR 5/8 C3P

8 Ap 0-20 2.5Y 4/3

7.5YR 4/6 C1P

Pore linings

3VF, 2F SL

3VCGR

1% mulch pieces

2Btg 20-59 2.5Y 7/6

2.5YR 4/6 F3P

Pore linings -- L

3COSBK WT @ 39 cm

10YR 6/2



2BC 59-74 2.5Y 6/4

2.5Y 6/6 C3D Fe masses -- SL

1COSBK


2.5Y 7/1 C3D In matrix

2Cg 74-150+

2.5Y 7/2

2.5Y 7/4 C3D Fe masses -- S 0SGR

9* Apg 0-13 10YR 4/2

10YR 4/4 C1D

Pore linings

2VF, 2F SL

3COSBK

2Bw 13-30 10YR 5/6

7.5YR 4/4 F1D Fe masses -- SL

1COGR


2BCg 30-65 2.5Y 5/2

7.5YR 5/8 C2P

Pore linings -- SL

2MSBK

2BCtg 65-150+

7.5YR 5/1

2.5Y 5/4 F2P Fe masses -- SCL 0MA




112


Matrix Color

Redox Color

Redox Description


10* Ap 0-7 10YR 3/2

10YR 5/6 F2P

Pore linings 3F SL 3MGR


2BAg 7-51 2.5Y 6/2


1F, 1M SL

1MSBK

Roots in upper 13 cm

5Y 4/1 7.5YR 5/8 C3P Fe masses


2Bt 51-107 5YR 4/6

2.5YR 4/4 F1P

Pore linings -- SCL

3COSBK


2BCg 107-150+

5GY 6/1

10YR 5/4 F2P Fe masses -- SL

2MSBK


*Met the depleted matrix (F3) Hydric Soil Indicator ‡ Met the sandy redox (S5) Hydric Soil Indicator

113

Appendix I. Pedon descriptions for RCK. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1* Apg 0-27 5Y 4/2 7.5YR 2.5/1 F3P

Mn masses 3VF, 3F L 3VCGR

5Y 5/3 F3F Fe masses



7.5YR 6/6 F1P Fe masses


2BCt 27-88 7.5YR 4/6

7.5YR 2.5/2 C2P

Fe masses -- SCL 1MSBK

2BC 88-133

7.5YR 4/4 2.5Y 6/4 M1P

Fe masses -- SL 1FSBK

7.5YR 3/4 F1F Fe masses

7.5YR 3/2 F3D Fe masses

2C 133-150+

10YR 4/4

10YR 6/4 C3F



2 Apg 0-9 10YR 4/2 2.5Y 8/6 F2P

Fe masses 3VF L 3VCGR



2Bt 9-69 10YR 4/6

2.5Y 2.5/1 F1P

Mn masses -- SCL 2MSBK


2BCt 69-118

7.5YR 4/6 2.5Y 6/4 F2P


2BC 118-147

10YR 5/4

7.5YR 2.5/1 F2P

Mn masses -- SL 2FSBK

2C 147-150+

7.5YR 5/6 -- -- -- -- LS 0SGR

114


Matrix Color

Redox Color

Redox Description


3* Ap 0-13 10YR 4/3

7.5YR 2.5/1 C2P

Mn masses 2VF L 3COGR





2Btg 13-34 5Y 4/2 7.5YR 4/6 C2P

Fe masses -- L 3COSBK



5Y 4/4 F2D Fe masses

2Bt 34-99 2.5Y 5/6 N 2.5/0 C1P

Mn masses -- CL 3COSBK


10YR 5/6 C3D Fe masses



2BCt 99-150+

10YR 4/6

10YR 2/1 C1P

Mn masses -- SCL 1MABK

5Y 7/3 C1P Fe masses



10G 6/1 C2P In matrix

10B 5/1 F1P In matrix

4* Apg 0-18 5Y 4/1 7.5YR 4/6 C2P


2.5Y 4/2


7.5YR 2.5/3 C2P Pore linings

2Bt 18-49 7.5YR 4/6

7.5YR 2.5/1 C1P

Mn masses -- L 3COABK


2BCt 49-90 10YR 4/4

7.5YR 2.5/1 F1P


5Y 6/3 F3P Fe masses

2BC 90-150+

10YR 5/4 5Y 7/3 C2P


WT @ 122 cm

10YR 3/4 C3F Fe masses


115


Matrix Color

Redox Color

Redox Description


5* Apg 0-15 2.5Y 4/2

7.5YR 2.5/3 F1P




2Bt 15-76 7.5YR 5/6

10YR 3/2 F2P

Fe masses -- SCL 2COSBK



N 5/0 F2P In matrix

2BC 76-106

10YR 4/6 2.5Y 6/4 M3P


WT @ 91 cm


5Y 6/1 M2P In matrix

2C 106-150+

10YR 4/4 -- -- -- -- LS 0SGR

6 Ap 0-12 2.5Y 5/3

7.5YR 2.5/1 C3P

Mn masses 2VF SIL 3COSBK

5YR 2.5/1 F2P Mn masses

5YR 5/8 M1P Fe masses 5YR 5/8 M1P Pore linings


10GY 5/1 F2P

In matrix

2Btg 12-31 2.5Y 4/2 -- -- -- -- L 3COSBK

2BC 31-85 7.5YR 4/6

7.5YR 2.5/1 F2P

Mn masses -- SL 1MSBK

2C 85-150+

10YR 5/4

7.5YR 4/4 F3D


WT @ 91 cm

2.5Y 6/3 F3D Fe masses

116


Matrix Color

Redox Color

Redox Description


7*± Apg 0-20 2.5Y 4/2 5Y 5/3 F3D

Fe masses 3VF, 3F SL 3MGR

10YR 2/1 C2D Mn masses





5Y 4/1 F2D In matrix

2Bt1 20-57 10YR 5/6

2.5YR 3/6 M3P

Fe masses -- SCL 3COABK

2.5Y 2.5/1 C2P Mn masses


5Y 5/4 C2P Pore linings


2Bt2 57-111

5YR 4/6

10YR 6/8 C2P


WT @ 107 cm

2.5Y 7/1 M2P In matrix

2BC 111-150+

10YR 4/6

2.5YR 4/6 C3P

Fe masses -- SL 1COSBK



10YR 7/2 M3P

In matrix

8* Apg 0-32 5Y 4/2 2.5Y 5/6 C3P Fe masses

3VF, 3F, 2M SL 3MGR

10YR 2/1 C1P Mn masses

5Y 4/3 C2F Fe masses




2Bt 32-71 10YR 4/4 5Y 6/3 C3P


10YR 2/1 C1D Mn masses


7.5YR 5/1 F3P

In matrix


2C1 71-113 10YR 4/6 5GY 4/1 F2P

In matrix -- S 0SGR

WT @ 107 cm

2C2 113-150+

7.5YR 4/6 5Y 5/3 M3P



7.5YR 2.5/1 C1P Mn masses

5PB 6/1 F3P In matrix

117

Location HorizonDepth (cm)

Matrix Color

Redox Color

Redox Description


9 Bt 0-51 7.5YR 5/8 5Y 4/3 C3P Fe masses 3VF SCL 2COABK

WT @ 15 cm

5Y 6/4 C3P Fe masses 5Y 2.5/1 C2P Mn masses


BC1 51-102 7.5YR 5/8 2.5Y 6/6 C3P



10GY 7/1 F1P Along pores

BC2 102-120

10YR 5/6

10YR 2/1 C1P

Mn masses -- SL 3C0SBK

10YR 5/8



5GY 6/1 M2P In matrix


C 120-150+

10YR 5/6 -- -- -- -- LS 0SGR

10 Ap 0-13 2.5Y 5/4

7.5YR 4/6 C1P

Fe masses

3VF, 3F, 2M SL 3COGR

WT @ 10 cm

10YR 2/1 F1P Mn masses



2Bt 13-39 5YR 4/6 5Y 6/4 C1P


2.5Y 6/6 C2P Fe masses N 2.5/0 F2P Mn masses

2BC 39-84 10YR 5/8

7.5YR 4/6 C3P

Fe masses -- SL 2MSBK

N 2.5/0 F2P Mn masses 5Y 5/1 C3P In matrix 5Y 6/2 C3P In matrix

2C/Cg 84-150+

5YR 4/6 10YR 5/8 M2P

Fe masses -- SL 0SGR

5Y 7/2 10YR 2/1 C1P Mn masses

5GY 5/1

118


Matrix Color

Redox Color

Redox Description


11 Ap/Apg 0-15 10YR 5/6 5Y 6/4 F1P

Fe masses -- L 3MGR

5Y 4/2 7.5YR 4/6 C3D Fe masses

2.5Y 5/6 C3D Fe masses


7.5YR 4/6 C1D Pore linings

2Bt 15-72 10YR 4/8

7.5YR 4/6 M3P

Fe masses -- CL 2MSBK

2.5Y 7/4 C2P Fe masses 5Y 5/1 M3P In matrix

2BC1 72-118

10YR 6/8 10Y 6/1 F3P In matrix -- L 1MSBK

5Y 7/1 5G 6/1 F1P In matrix

2BC2 118-150+

7.5YR 5/6

7.5YR 3/4 C3D

Fe masses -- SL 2COSBK

WT @ 122 cm

2.5Y 7/1




12 Ap 0-20 2.5Y 3/3

5YR 2.5/1 F2P

Mn masses 3F, 1M SL 3COGR


2Bt 20-43 7.5YR 4/6

7.5YR 2.5/1 C1P

Mn masses 1VF SCL 3MABK

5Y 6/3 C2P Fe masses 10YR 5/6 C2D Pore linings

2BC 43-88 7.5YR 4/6

7.5YR 2.5/1 F3P

Mn masses -- SL 1COSBK


2CB 88-150+

7.5YR 4/6 5YR 4/6 F3D

Fe masses -- S 0SGR

13*± Apg 0-22 2.5Y 5/2

2.5Y 2.5/1 C1D

Mn masses 3VF, 3F SL 3MGR

5YR 3/3 C2P Fe masses 3COGR

2BCt1 22-67 5YR 4/6 N 2.5/0 C1P

Mn masses -- CL 0MA


2BCt2 67-123

7.5YR 5/6

2.5Y 2.5/1 F1P


WT @ 76 cm

5Y 6/3 M3P Fe masses


2C 123-150

7.5YR 4/4 -- -- -- -- S 0SGR

119


Matrix Color

Redox Color

Redox Description


14 Ap 0-26 2.5Y 5/3

7.5YR 3/1 C1P

Mn masses 2VF, 2F SL 3COGR


2.5Y 6/4 F1F Pore linings

2BCt 26-91 7.5YR 4/6 5YR 4/4 F2P


WT @ 91 cm


2BC1 91-114

7.5YR 4/6 5YR 4/4 F2P

Fe masses -- SL 1MSBK

N 2.5/0 C1P Mn masses

2BC2 114-136

7.5YR 5/6 5YR 4/4 C1P

Fe masses -- LS 1MSBK


2C 136-150

10YR 5/6

2.5YR 3/1 C3P

Mn masses -- LS 0SGR



*Met the depleted matrix (F3) Hydric Soil Indicator ± Met the Fe/Mn masses (F12) Hydric Soil Indicator

120

Appendix J. Pedon descriptions for SB. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1* Ap 0-12 2.5Y 4/3 -- -- -- -- SL 3COGR

2Btg 12-45 2.5Y 4/1

10YR 5/8 M2P Fe masses -- CL 3COSBK

5Y 6/1 C3D In matrix

2.5Y 6/1 M2F In matrix

2BCg 45-91 5Y 5/2 10YR 4/6 C2P Fe masses -- LS 3MGR

WT @ 91 cm

2C 91-150+ 5Y 3/1

2.5Y 5/4 F3P Fe masses -- LS 0SGR

3* Apg 0-12 2.5Y 4/2 -- -- -- -- SL 1VFGR

2ABg 12-35 2.5Y 4/2

10YR 4/6 C2D Fe masses -- SL 3COSBK

2.5Y 7/1 F1D In matrix

2Bt1 35-52 7.5YR 4/6

10YR 5/6 C1F Fe masses -- SCL 3MSBK

5GY 5/1 F1P In matrix

2Bt2 52-64 2.5Y 4/2

7.5YR 4/6 C2P Fe masses -- SL 2MSBK


2Bt3 64-105

2.5Y 4/3

7.5YR 4/6 F2P Fe masses -- SCL 3COSBK


2BCg 105-150+ 5Y 4/1

10YR 5/6 F2P Fe masses -- LS 1VFGR

WT @ 122 cm

4 Apg 0-6 10YR 4/1

5YR 5/8 F3P

Fe concretions 2F SL 2MSBK

2BCt 6-41 10YR 4/3

5YR 5/8 C2P Fe masses -- SCL 0MA

25% shell fragments

5B 6/1 C2P In matrix

2BC 41-60 10YR 5/3

5YR 7/8 C1P Fe masses -- SL 1MGR

2BCg1 60-70 5GY 5/1 -- -- -- -- LS 3MGR

2BCg2 70-150+

5GY 4/1 -- -- -- -- LS 3COGR

121


Matrix Color

Redox Color

Redox Description


5 Ap 0-23 2.5Y 3/1 -- -- --

1M, 1VF SL 3FGR

2ABt 23-73 2.5Y 3/1

10YR 7/6 F2P Fe masses -- SL 2COSBK

N 2.5/0 C1P Mn masses


2Btg 73-90 2.5Y 4/1

10YR 4/3 C2P Fe masses -- SCL 2COSBK


N 3/0 M3P Mn masses

2.5Y 7/1 F2D In matrix

2Cg1 90-107 5Y 5/1

2.5Y 5/6 C2P Fe masses -- S 0SGR

2Cg2 107-150+ 5Y 5/2

10YR 5/6 C3P Fe masses -- LS 0SGR



6 Ap 0-11 2.5Y 3/2 -- -- -- 3F SL 3FGR

2BA 11-47 2.5Y 5/3

10YR 5/8 C2P Fe masses -- SL 2MSBK


2Btg 47-85 5Y 5/2 10YR 5/8 C3P Fe masses -- SCL 3COSBK


7.5YR 3/1 M3P Fe masses

2Abg 85-95 N 2.5/0 -- -- -- -- SL 0MA woody mat

2Cg1 95-114

2.5Y 4/2

10YR 4/6 M3P Fe masses -- S 0SGR

2Cg2 114-150+ 5Y 4/1 -- -- -- -- S 0SGR

WT @ 122 cm

7* Ap 0-18 2.5Y 4/3 -- -- -- 3F SL 3MGR

2BCtg 18-57 5Y 5/2 7.5YR 5/8 C1P Fe masses -- SL 1COSBK

2.5Y 6/1 M3P In matrix

2C 57-87 2.5Y 4/3

10YR 5/8 F1D Fe masses -- SCL 0MA


2Cg 87-150+

2.5Y 4.2

7.5YR 5/8 F2P Fe masses -- SCL 0MA

5G 4/2 C3P In matrix N 6/0 C3P In matrix

122


Matrix Color

Redox Color

Redox Description


8* Ap 0-15 10YR 3/1 -- -- -- 2F SL 3FGR gravelly

2BAg 15-45 2.5Y 4/2

7.5YR 5/8 M3P Fe masses -- SL 2MSBK

2.5Y 3/1 C3F Mn masses

5Y 6/1 M3D In matrix

2Btg 45-70 2.5Y 5/2

2.5Y 3/3 F3F Fe masses -- SL 2MSBK


2.5Y 6/1 C3F In matrix

2BCtg 70-128 5Y 4/1

10YR 5/8 F1P Fe masses -- L 1COSBK

5Y 5/1 C2F In matrix

2BCg 128-136

10YR 4/1

10YR 4/6 M3P Fe masses -- SL 1MSBK


2Cg1 136-148 N 4/0

7.5YR 5/8 M1P Fe masses -- LS 0SGR

2Cg2 148-150+ N 4/0 -- -- -- -- LS 0SGR

9* Ap 0-17 10YR 3/1 -- -- -- 1M SL 3MSBK

2BAg 17-40 2.5Y 4/2

10YR 5/6 C3P Fe masses -- SL 3COSBK 15% shells

N 3/0 F3P Mn masses

2Bt1 40-75 2.5Y 5/4 5B 5/1 C3P In matrix -- SCL 2COSBK 50% shells

2Bt2 75-96 10YR 5/4

5GY 4/1 C2P In matrix -- SCL 3COSBK 50% shells

2Btg 96-127 5B 5/1

10YR 5/8 M1P Fe masses -- CL 3COSBK

2BC 127-150+

10YR 5/8

2.5Y 4/1 C3D In matrix -- SCL 3COSBK 50% shells

10 Ap 0-38 10YR 3/1 -- -- -- 3F SL 3COGR 5% gravel

2BAtg 38-67 2.5Y 4/2

7.5YR 5/8 M3P Fe masses -- SCL 3COSBK

2.5Y 7/1 M3D In matrix

2Bt 67-107

2.5Y 6/3

10YR 5/6 M3D Fe masses -- L 3COSBK

sandy clay lenses

5B 7/1 M3P In matrix

2Btg 107-150+

10YR 5/1

7.5YR 5/8 F1D Fe masses -- SCL 3COSBK

sandy clay lenses

N 7/0 F2P In matrix *Met the depleted matrix (F3) Hydric Soil Indicator

123

Appendix K. Pedon descriptions for SCW. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1 Apg 0-20 7.5YR 4/2 -- -- -- -- SL 1FGR

organic materials present

2Cg 20-51 7/1 5B 10YR 7/8 C2P

Pore linings -- S 0SGR

2C1 51-74 7.5YR 6/8

7.5YR 8/0 C2P


2C2 74-112

7.5YR 7/6

7.5YR 6/8 C2D


2C3 112-145

7.5YR 6/8

7.5YR 8/6 C2D

Fe masses -- SL 0MA

WT @ 127 cm

2 Ap 0-13 10YR 5/3 -- -- -- -- SL 0MA

5cm of organic matter below A horizon in plug

2BCg 13-30 10YR 4/1 -- -- -- -- SL 2MPL

2BC1 30-46 10YR 4/3

7.5YR 5/6 C2P

Fe masses -- SL 1MPL

2BC3 46-64 7.5YR 5/8 -- -- -- -- SL 0MA

2Cg 64-94 7.5YR 5/0

7.5YR 6/6 F1P

Fe masses -- SL 0MA

7.5YR 7/0 F1F In matrix

2C1 94-140

7.5YR 3/0 -- -- -- -- SL 0MA

2C2 140-155

10YR 7/3

10YR 7/6 C2D

Fe masses -- SL 0MA

5/1 5B at upper boundary

3γ Ap1 0-18 10YR 3/3

5YR 5/8 C1P

Fe masses

1F, 1M SL 1FPL

organic material below A horizon present in plug

7.5YR 6/0 F1P In matrix

Ap2 18-28 7.5YR 5/6 -- -- -- -- LS 0SGR

2Cg 28-76 2.5Y 6/2

2.5Y 4/0 C2D In matrix LS 0SGR sulfur smell

7/1 5B

common, medium clay inclusions

2C1 76-89 7.5YR 6/8

10YR 7/6 C2P


2C2 89-107

10YR 8/4 -- -- -- -- LS 0SGR

124


Matrix Color

Redox Color

Redox Description


4‡ Ap 0-8 10YR 4/4 -- -- -- -- SL 2MPL

2BC 8-23 10YR 7/2

7.5YR 6/8 C2P

Fe masses -- LS 0SGR clay lenses

2C1 23-94 7.5YR 6/8 -- -- -- -- LS 0SGR

2C2 94-109

10YR 7/4 -- -- -- -- S 0SGR

WT @ 109 cm

2Cg 109-142

4/1 10BG -- -- -- -- LS 0SGR

5* Ap 0-15 7.5YR 5/4 -- -- -- 1F SL 1FPL

10% rounded quartz gravel

2Cg 15-30 7.5YR 6/0 -- -- -- -- SCL 0MA

30% gravel; cobble layer below 30 cm

6* Ap 0-15 7.5YR 4/4

7.5YR 5/8 C1P

Fe masses -- SL 2MPL

2BCg 15-33 2.5Y 7/0

7.5YR 6/8 C2P

Fe masses -- SL 0MA

2C 33-58 7.5YR 6/6 -- -- -- -- S 0SGR

2Cg 58-74 7.5YR 6/0 -- -- -- -- S 0SGR

2C' 74-84 7.5YR 6/8 -- -- -- -- S 0SGR WT @ 84 cm

2C'g 84-137

7.5YR 7/0 -- -- -- -- S 0SGR

γ Met the hydrogen sulfide (A4) Hydric Soil Indicator *Met the depleted matrix (F3) Hydric Soil Indicator ‡ Met the sandy redox (S5) Hydric Soil Indicator

125

Appendix L. Pedon descriptions for SWS. All abbreviations are according to the Field Book for Describing and Sampling Soils (Schoeneberger et al., 1998).


Matrix Color

Redox Color

Redox Description


1 Ap1 0-25 2.5Y 5/4

10YR 5/8 F1P Fe masses 2F SL 3VCGR 5% medium

5Y 3/1 10YR 4/3 C3P Fe masses

mulch pieces

Ap2 25-44 2.5Y 3/1

10YR 4/6 F1P Fe masses -- SL 3COGR

2.5Y 5/1 FCF In matrix

2BAg 44-79 7.5YR 4/6


2% thick mulch pieces

N 3/0 5G 6/1 C3P In matrix WT @ 58 cm

2.5Y 4/1

2BCg 79-104

2.5Y 6/1

5YR 4/6 F3P Fe masses -- SL 3COSBK



2Cg 104-150+

5GY 4/1 -- -- -- -- SL 0MA

2 γ Apg 0-10 N 2.5/0

5GY 5/1 F3P In matrix 3F SL 3MGR Sulfur smell

10YR 5/2

ABg 10-30 2.5Y 4/1

10YR 5/8 C3P Fe masses -- SCL 3COSBK

2.5Y 5/3

10YR 7/1 F3P

Along pores

2Abg 30-60 5Y 4/2 5YR 5/8 F3P

Pore linings -- SL

5G 5/1 F3P In matrix 3MGR Dense root remains

2Bt 60-92 7.5YR 5/8

N 2.5/0 F3P Mn masses -- SCL 3MSBK

5Y 6/3 F3P Fe masses

2BCg 92-150+

5BG 4/1 -- -- -- -- SL 3MSBK

3 Ap 0-23 10YR 6/6

10YR 4/6 C3F Fe masses 1F SL 3VCGR

10YR 2/1

10YR 6/1 C3P

Along pores

2BC 23-46 2.5Y 6/3 -- -- -- -- LS 0SGR

2BCg 46-60 2.5Y 6/1


2.5Y 4/2

2C 60-130

7.5YR 5/8 -- -- -- -- S 0SGR

WT @ 80 cm

126


Matrix Color

Redox Color

Redox Description


4 Ap/Apg 0-25 N 2.5/0

7.5YR 7/8 F1P

Pore linings 3VF SL 3MGR

2.5Y 5/3

2BA 25-45 2.5Y 5/4

2.5Y 7/1 F1P In matrix -- SL 2MSBK

2Ab 45-73 10YR 3/1 -- -- -- -- LS 3MGR Sulfur smell

2Bt 73-104

10YR 5/8

2.5YR 3/4 F2P

Fe concretions -- SCL 2MSBK

2BCg 104-150+ 5B 4/1 -- -- -- -- SL 3MSBK

5 Ap/Apg 0-12 N 2.5/0

7.5YR 5/8 C3P

Pore linings 3M SL 3VCGR

2.5Y 5/3

10YR 7/1 C2P

Along pores

2Bw 12-30 10YR 5/6

5YR 5/8 C3P Fe masses 1M SL 3COSBK

2.5Y 7/1 F2P

Along pores

5YR 6/1 C3P

Along pores

2BC1 30-40 5Y 3/1 -- -- -- -- SL 0SGR

2BC2 40-52 10YR 5/8 -- -- -- -- S 0SGR

2BC3 52-73 10YR 4/6

2.5YR 4/6 C3P Fe masses -- SL 3COSBK

2.5YR 3/2 F3P Fe concretions

N 7/0 F1P In matrix


2BCg 73-150+ 5G 4/1 -- -- -- -- SL 3COSBK

WT @ 122 cm

6 Ap 0-22 5Y 3/1 2.5Y 6/6 C2P Fe masses 3VF SL 3COGR

2.5Y 5/6 F2P

Pore linings 3F


2BA 22-40 2.5Y 6/4


2.5Y 3/1 C2D Mn masses


2BC 40-52 10YR 4/4

10YR 5/6 C2D Fe masses -- SL 1MSBK


2BCt 52-95 10YR 5/6 5Y 6/6 F2P Fe masses -- SCL 1COSBK


2.5YR 3/2 C3P Mn masses


2BCg 95-150+

5GY 5/1 -- -- -- -- SL 2MSBK

127


Matrix Color

Redox Color

Redox Description


7* Apg 0-20 2.5Y 5/2

N 2.5/0 M2P Mn masses 3VF SL 3COGR

5YR 3/4 F1P

Pore linings 3F


2BA 20-47 2.5Y 5/4

2.5YR 6/6 F1P Fe masses -- SL 3COSBK



2Bt 47-98 7.5YR 5/6

2.5Y 6/8 C2P Fe masses -- SCL 2COSBK

2.5YR 2.5/1 M3P Mn masses

5YR 2.5/1 F2P Mn nodules

10B 8/1 C1P In matrix

2BCg 98-150+ N 5/0 -- -- -- -- SL 3COSBK

8 Ap/Apg 0-26 5Y 4/2 10YR 6/6 F3P Fe masses -- SL 3COGR

10YR 3/1



N 5/0 F2P In matrix 5Y 6/2 C2P In matrix

2BA 26-60 2.5Y 5/3

5YR 4/6 F2P Fe masses -- SL 2MSBK




2Bw 60-112

7.5YR 5/8

2.5Y 6/6 C3P Fe masses -- SL 2MSBK




2BCg 112-150+

5GY 5/1

5GY 4/1 F3F In matrix -- SL 3FSBK

128


Matrix Color

Redox Color

Redox Description


9* Apg1 0-15 2.5Y 4/1

N 2.5/0 M3P Mn masses 3VF SL 3VCGR

5Y 5/4 C2P Pore linings 3F

2.5Y 6/4 C1D Pore linings

5PB 5/1 C3P In matrix

Apg2 15-51 2.5Y 4/2

N 2.5/0 C3P Mn masses -- SL 3MGR




2Bt 51-92 10YR 4/6

2.5Y 5/3 C3P Fe masses -- CL 3COSBK

10YR 5/8 5Y 7/2 C2P In matrix


2BC 92-101

10YR 5/6

2.5Y 5/3 C1P Fe masses -- LS 0SGR

10YR 5/8 C1D Pore linings


2BCt 101-118

7.5YR 5/8

5YR 5/8 C3D Fe masses -- SCL 3COSBK

5PB 7/1 C3P

Along pores

2BCg 118-150+ N 5/0 N 4/0 C3F In matrix -- SL 2MSBK

WT @ 122 cm

129


Matrix Color

Redox Color

Redox Description


10 Ap 0-15 7.5YR 3/1

2.5Y 6/3 C3P Pore linings 3VF SL 3COGR

10YR 5/8 F1P Pore linings 3F

2BA 15-68 2.5Y 5/3

2.5YR 3/4 F2P Fe masses -- SL 3MSBK

2.5Y 5/6 C2D Fe masses


5PB 6/1 F2P In matrix

N 7/0 F1P In matrix 5Y 4/1 C1P In matrix

2BC1 68-86 2.5Y 5/6

10YR 4/4 C3P Fe masses -- SCL 1MSBK


5YR 2.5/1 F3P Mn nodules


5G 6/1 F2P In matrix

2BC2 86-116

5YR 5/8

2.5Y 7/6 F1P Fe masses -- SL 2COSBK



2BCg 116-150+ 5G 5/1 -- -- -- -- SL 3COSBK

γ Met the hydrogen sulfide (A4) Hydric Soil Indicator *Met the depleted matrix (F3) Hydric Soil Indicator

130

Appendix M. Depth contrasts for selected variables at each site using Wilcoxon Sign-Rank Test. Differences are significant where p ≤ 0.05.

0-15 cm BCK pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.5781 0.0469* 0.9375 0.1563 0.6875 0.0625 <0.0001* 0.7500 0.4063 90-105 0.3750 0.0625 1.0000 0.5625 0.0625 0.0625 0.5000 0.0625

0-15 cm

BCK Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.9375 0.3750 0.0313* 0.5781 0.4688 0.1563 0.0625 0.0625 0.0313* 90-105 0.5625 0.1250 0.1875 0.0625 0.3750 0.0625 0.2500 0.1250 0.0625

0-15 cm

CCW pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.0015* 0.0005* 0.7436 0.0098* 0.0010* 0.0024* <0.0001* 0.0078* 0.1016 90-105 0.0008* <0.0001* 0.3778 0.4238 0.0148* 0.3467 0.0078* 0.5054

0-15 cm

CCW Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0005* 0.0049* 0.0156* 0.0005* 0.0005* 0.6621 0.0020* 0.0024* 0.0005* 90-105 0.0005* 0.1116 <0.0001* 0.0002* <0.0001* 0.5707 0.0020* 0.0001* <0.0001*

0-15 cm

DC pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.9502 0.0005* 0.3394 0.1294 0.9697 0.0068* <0.0001* 0.8828 0.0020* 90-105 0.0879 0.0005* 0.1514 0.2661 0.9282 0.0771* 0.1250 0.0029*

0-15 cm

DC Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0640 0.0024* 0.5811 0.0005* 0.2480 0.0342* 0.0625 0.0005* 0.0005* 90-105 0.6772 0.0005* 0.0146* 0.0005* 0.1533 0.0093 0.0625 0.0010* 0.0005*

131

0-15 cm MAN pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.2500 0.0625 0.1250 0.4375 0.1250 0.0625 0.0005* 0.7500 0.0625

0-15 cm

MAN Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.1250 0.0625 0.2500 0.0625 0.1875 0.0625 0.1250 0.0625 0.0625

0-15 cm

MATTA pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.0039* 0.0020* 0.2324 0.6250 0.0020* 0.0195* 0.0079* 0.0840 0.0391* 90-105 0.0313* 0.0313* 0.0313* 0.0313* 0.0313* 0.0313* 0.0313* 0.6250

0-15 cm

MATTA Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0840 0.4922 0.0801 0.0020* 0.0625 0.0547 0.0039* 0.0020* 0.1309 90-105 0.0313* 0.0625 0.0313* 0.0313* 0.3750 0.0313* 0.0625 0.0313* 0.4375

0-15 cm

MTS pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.2852 0.0010* 0.0605 0.6836 0.1445 0.0234* <0.0001* 0.9902 0.3076 90-105 0.0015* 0.0005* 0.0161* 0.9263 0.0093* 0.0122* 0.1045 0.4102

0-15 cm

MTS Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0098* 0.2334 0.0078* 0.0518 0.0635 0.0010* 0.0313* 0.0010* 0.1689 90-105 0.3394 0.3013 0.0015* 0.0005* 0.4238 0.0015* 0.0313* 0.0005* 0.0005*

132

0-15 cm

RCK pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.0024* 0.0002* 0.0034* 0.7869 0.0215* 0.0005* <0.0001* 0.6563 0.0002* 90-105 0.0194* 0.0001* 0.0005* 0.0040* 0.0012* 0.4532 1.0000 0.0001*

0-15 cm

RCK Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0002* 0.0002* 0.0010* 0.0002* 0.0771 0.0002* 0.0005* 0.0002* 0.0002* 90-105 0.0001* 0.0023* 0.0001* 0.0001* 0.0134* 0.0001* 0.0002* 0.0001* 0.0001*

0-15 cm

SB pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.2031 0.0273* 0.4648 0.0273* 0.0039* 0.0039* 0.0880 0.3164 0.0039* 90-105 0.4512 0.0068* 0.6377 0.7500 0.1973 0.2686 0.4805 0.0029*

0-15 cm

SB Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0273* 0.4961 0.0156* 0.0391* 0.2969 0.0742 0.6875 0.0117* 0.9102 90-105 0.8818 0.2695 0.6836 0.0049* 0.2832 0.6826 0.0039* 0.0049* 0.1016

0-15 cm

SCW pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.5000 0.0313* 0.0938 0.0625 0.0313* 0.2500 <0.0001* 1.0000 0.1563 90-105 0.4688 0.0313* 0.2188 0.0313* 0.0313* 0.0313* 0.6875 0.6250

0-15 cm

SCW Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.1563 0.0938 0.0625 0.0313* 0.1875 0.1563 0.5000 0.0625 0.0313* 90-105 0.3125 0.0313* 0.1250 0.0625 0.1875 0.8438 1.0000 0.0313* 0.0313*

133

0-15 cm

SWS pH %C Mass Carbon % Sand % Silt % Clay Bulk Density P K 30-45 0.0020* 0.0010* 0.0098* 0.6621 0.9492 0.4512 <0.0001* 0.0010* 0.0010* 90-105 0.0010* 0.0010* 0.0020* 0.5566 0.7109 0.5566 0.9023 0.0010*

0-15 cm

SWS Ca Mg Zn Mn Cu Fe B %N C:N 30-45 0.0010* 0.0010* 0.0527 0.4004 0.0049* 0.5049 0.0010* 0.0010* 0.5615 90-105 0.0830 0.0010* 0.1191 0.4648 0.4785 0.8984 0.0010* 0.0010* 0.0537

134

VITA Gabriela I. Fajardo was born on June 28, 1978 in Mountain View, California. As a member of a Navy family, she has had the opportunity to live in several states. Gabriela attended Orange Park High School in Orange Park, Florida, and spent her senior year in Ceiba, Puerto Rico. In 1996, she graduated from Roosevelt Roads High School and enrolled at Virginia Tech in the fall of that same year to pursue her undergraduate degree in Environmental Sciences (Plant Resources). After completion of her Bachelor of Science degree in May 2000, Gabriela worked in Ashton, Maryland and Roanoke, Virginia before returning to Virginia Tech in the fall of 2002 to pursue a Master of Science degree. Under the advisement of Dr. W. Lee Daniels, she focused on soils and wetland science. As a graduate student, she had the opportunity to assist and teach Soil Microbiology Laboratory and Geomorphology. In September 2004, Gabriela joined Williamsburg Environmental Group, Inc. as a soil scientist. Gabriela graduated from Virginia Polytechnic Institute and State University with a Master of Science degree in Crop and Soil Environmental Sciences in May 2006.

physical and chemical soil properties of ten virginia

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