Soil Analysis Soil Science

By Carolyn Stevens, Mohammed Taha, Todd De Jong, Marissa Cleroux

12/9/2011

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Table of Contents

Introduction................................................................................................Page 2

Soil Forming Factors.................................................................................Page3

Classification of Soil...................................................................................Page4

Conclusion..................................................................................................Page 8

Appendix.....................................................................................................Page9

References...................................................................................................Page19

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Introduction

Soil samples were taken from Milford, Nova Scotia on September 29, 2011. The area is

located approximately 56 km North East of Halifax in a rural, primarily farmland setting. The

purpose of sampling, field analysis, and subsequent laboratory testing was to characterize and

name the soil according to the Canadian Soil Classification System. This report will detail field

and laboratory work related to the project and present the analytical results in a manner that will

facilitate an understanding of soil horizons and soil composition.

The soil samples were taken beside a pasture at the edge of a forest in Milford, Nova Scotia

(+45° 2' 8.86", -63° 26' 27.89"). It was a clear, sunny day and the temperature was around 17° C.

In the days leading up to the sampling, many rain

events had occurred leading the soil to be

moistened. At the location, a hole was dug with

the dimensions 1 meter wide, by 1 meter in

length, and 0.56 meters deep. Any further depth

was prevented due to the tough clay, inhibiting

the equipment from digging any further. Despite

this, representative samples were able to be

obtained from the Ah horizon and B horizon, as

well as two core samples, but not from the C

horizon due to the limitation in depth. Proper

procedure and protocols were followed

throughout the sampling and laboratory analysis.

Brown sandstone from the sample site was

obtained from the sample site, which gave clues as to the original parent material of the soil. The

parent material was a dusky red clay loam till from red shales and mud stone, with numerous red

and brown sandstone fragments (refer to Figure 8).

Figure 1: Site Sketch

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Soil Forming Factors

Parent Material: Milford sits atop the Windsor Group formation (refer to Figure 7) which it

mainly comprised of siltstone, sparse gypsum, and shallow marine limestone bedrock. This

bedrock is of a reddish brown clay loam, with a lighter shade sitting above a darker shade of red.

This coincides with the parent material, which was a dusky red clay loam till from red shales and

mudstone, with numerous fragments of red and brown sandstone.

Topography: The location where the soil was formed consisted of gently rolling drumlins left in

the wake of the last ice age with generally moderate slopes. In this area, the surface drainage rate

is moderate while the internal drainage is much slower due to the higher amounts of clay (refer

to Table 9). Water movement through the Ah horizon was found to be at a rate of 2.68 m/day,

whereas the water movement results from the B horizon are still pending. This suggests a very

poor hydraulic conductivity due to an increase in clay particles in that horizon.

Climate: The climate for Elmsdale, Milford is determined based on its inclusion in the Atlantic

Maritime region where the Atlantic Ocean has a strong influence on this area’s climate. The

presence of an ocean causes the area to produce cooler summers, yet warmer winters all with a

humid climate. The winter temperatures average around -4°C while the summer temperatures

have an average around 17°C (refer to Table 9). Annual precipitation for this area averages

around 1453 mm (refer to Table 10). High precipitation and a humid climate also indicate that

the region is prone to storm events. This type of climate facilitates good soil forming conditions.

Biota: The soil was sampled on the boundary between a forested area and a farmer’s field where

cows were led out to graze (refer to Figure 4). The first few centimeters of the soil had grass,

causing fixation reactions that contributed decayed organic material, organics acids, and

structure to the soil provided by the roots. In addition to providing structure, these roots provide

a barrier to slow the natural processes of erosion. Within the horizons, 23.3 mg/g of organics

were found in the A horizon while 1.31 mg/g were present in the B horizon. This contributes to

water retention, adds structure by acting as a gluing agent, supplies acid through decay, and

serves as a nutrient reserve for the soil.

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Time: The soils in the Milford area have been forming under these conditions since the last ice

age occurred, approximately 11,000 years ago.

Soil Classification

Based off of the various analyzed criteria, it was determined that the soil at the designated

sampling site was of the Humo-ferric pdozol great group. The soil has a reddish B horizon with

an Ah horizon (refer to Figure 1). The B horizon was at least 10 centimetres thick (refer to

Figure 1) and the organic carbon within the Ah horizon was found to be 2.33%. This is within

the 0.5-5% range stated in the Canadian System of Soil Classification. The cation exchange

capacity (CEC) was found to be 7.5 cmolc/kg in the B horizon which borders the 8 cmolc/kg for a

Humo-ferric podzol. With all of these attributes taken into account, it can be said that the soil

sample obtained from Milford is a Humo-ferric podzol.

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Figure 9: Caparisons of Horizons, Milford Soil

Ah Horizon

B Horizon

Ah Horizon

B Horizon

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Field Capacity Description (refer to Tables 5 and 6):

The original field moist capacity for the Ah horizon (54%) was more than that of the

disturbed soil (35.1%). In addition, the original field moist capacity for the B horizon (28%) was

only slightly higher than that of the disturbed soil (26.6%).

The disturbed Ah horizon soil was below field capacity by approximately 18.9% while

the disturbed B horizon soil was only 1.4% less than the original field moist capacity.Overall, the

Ah horizon holds more water due to the humic and organic compounds in the soil. In addition, as

the porosity decreases in a soil so too does the field capacity. The porosity in the B horizon is

much less, causing it to be able to hold far less water than the Ah horizon. In regards to texture,

the Ah horizon has a larger field capacity due to the larger aggregate size creating larger, more

open pores due to the reduced clay content. The higher clay content of the B horizon caused the

Ah horizon to have the larger field capacity.

Hygroscopic Water Content (refer to table 7):

In the soil sample, the Ah horizon had a larger hygroscopic moisture content than the B

horizon due to the presence of more organic material. The concentration of organics within the

Ah horizon is 23.3 mg/g or organics while the B horizon contained only 1.31 mg/g of organics.

This allows for the organic material to retain more water than the soils in the B horizon, causing

the hygroscopic content to be larger. The hygroscopic water content of the Ah horizon was

2.58% while the content of the B horizon was just 0.6%.

Bulk Density Explanation (refer to Table 1):

Bulk density is the weight of a given volume of soil in its natural, undisturbed condition.

It depends on the structure, size, pores, and the make-up of the soil horizon mineral content.

Typically, organic soils have lower bulk densities than the more compacted soils below. In the

soil samples that were taken, the Ah horizon bulk density was 1.04 g/mL and the B horizon was

1.46 g/mL.

Particle Density is similar to bulk density; however, where the bulk density includes the

volume of air, water, and solids content of a soil, the particle density is simply the volume of the

solids content. Solids content includes the minerals and organic matter. For the Ah horizon, the

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particle density is 2.26 g/mL whereas the B horizon had a value of 2.70 g/mL. According to

these values, the B horizon had the greater solids content.

Porosity is another important parameter in regards to bulk density, and is defined as the

amount and size of pores and the total amount of water that a soil can hold. In the Ah horizon

where the clay content was less, there was a porosity of 52% while the B horizon, which had

greater clay content, had a porosity of 46%. The Ah horizon had the greater porosity because of

the greater uniformity in particles size and shape.

Organic Carbon (refer to Table 8):

Organic Carbon levels in the Ah horizons were measured to be 2.33% whereas the B

horizon contained a meager 0.131%. The increased organics in the Ah horizon is due to the

increased proximity to the organic layer at the surface, in addition to the roots of plants and

decaying material that reach into the horizon itself. The sparse organics content in the B horizon

is a reflection of the minute amount that managed to leach from the Ah horizon down to the B

horizon.

Cation Exchange Capacity (refer to Tables 2 and 3):

The cation exchange capacity (CEC) Is higher in the Ah horizon with a value of 12.028

cmolc/kg than in the B horizon with 7.5 cmolc/kg. Once more, this is due to the higher organic

content in the Ah horizon. In addition, this higher CEC allows for more hydrogen ions to be

exchanged and retained, as well as the roots contributing increased hydrogen through root

microbe respiration. This is reflected in the pH value of 6.63 in the Ah horizon as opposed to the

6.74 in the B horizon.

Soil Water Movement

Soil water movement is the measure of the rate at which water can pass through the soil

horizon and is related to the porosity in the given horizon. For this sample, the Ah horizon had a

hydraulic conductivity of 2.68 m/day. On the other hand, the B horizon results are still pending

as the water has not moved in over a week. Based off of this data, it can be said that the water

movement through the Ah horizon is much greater than the B horizon, but there is currently no

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way to give a direct ratio. Slower water movement through the B horizon can be attributed to the

higher clay content plugging up the larger pores in the aggregates.

Soil Structure

The soil sample exhibited a spherical aggregate shape in both the Ah horizon and the B

horizon, which tends to be common in soils containing an Ah horizon. In addition, the shape is

granular in both with a bit of a crumb structure for the Ah horizon. This structure is typical of

surface horizons prone to biological activity, such as that provided by the adjacent forest and

cow pasture. Finally, the aggregate size was approximately 3 mm to 1 cm in the Ah horizon and

less than 1 mm in the B horizon.

Soil Mineral Content

In the soil horizons, the sand content was relatively the same in both horizons, valued at

67.87% and 68.53% for the Ah and B horizons respectively. The Ah had a higher silt content

compared to the B horizon (29.33 % to 19.67 %), while the B horizon had larger clay content

(11.8 % to 2.8 %). There is more clay in the B horizon and less silt because of illuviation, which

is the removal of a material from one layer to another. So while the clay from the Ah horizon is

illuviated into the B horizon the Ah horizon silt content increases due to deposited material.

Conclusion

On September 29, 2011, soil samples were taken from Milford Nova Scotia. The purpose

of this soil project is to learn how to take a representative sample of soil and interpret the results

to characterize the soil and its genesis. This is done through laboratory determination of several

important physical, chemical and biological properties. The soil sampled at Milford was of the

Humo-ferric podozol great group, with Ah and B horizons. Due to organic inputs and differences

in clay content, the characteristics of the two horizons greatly differed and added their unique

properties to the soil landscape in Milford.

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Appendix A

Table 1: Bulk Density, Particle Density and Porosity

Ah Horizon B Horizon Weight of the cylinder plus soil 157.7 g 167.1 g

Weight of the cylinder alone 130.6 g 130.6 g

Soil weight 27.1 g 36.5 g

Volume of soil 25mL 25mL

Bulk Density 1.04 g/mL 1.46 g/mL

Volume of soil solids and water

mix

62 mL 63.5 mL

Volume of water added 50 mL 50mL

Volume of soil solids 12 mL 13.5 mL

Particle Density 2.26 g/mL 2.70 g/mL

Pore volume 13 mL 11.5 mL

Porosity 52 % 46 %

Table 2: Cation Exchange

Horizon: Ah Recorded Dilution Conversion Ca

++ 4.2-2.95 = 1.25mg/L x

20 = 25 mg/L as

CaCO3

X 10

250mg/L as CaCo3 x .400

(to convert to Ca++

)=

100mg/L as Ca++

Mg++ Total Hardness – Ca

++

Hardness = 280 –

250= 30mg/L as

CaCO3

N/A 30 mg/L as CaCO3 x .243

(to convert to Mg++

) =

7.294 mg/L as Mg++

Na+ N/A N/A N/A

K+ 2.5 mg/L as K + X 100 250 mg/L as K

+

Al+++ 0.013 mg/L as Al

+++ X 10 0.13 mg/L as Al

+++

pH 6.63 N/A

Total Hardness 0.7 x 20 = 14mg/L as

CaCO3

X20 280mg/L as CaCO3

Horizon: B Recorded Dilution Conversion

Ca++

0.6 x 20= 12 mg/L as

CaCO3

X 10

120 mg/L as CaCO3 x

.400 (to convert to Ca++

) =

48 mg/L as Ca++

Mg++ Total Hardness – Ca

++

Hardness = 222 – 120

= 102 mg/L as CaCO3

N/A 102 mg/L as CaCO3 x .243

= 24.79 mg/L as Mg++

Na+ N/A N/A N/A

K+ 1.10 mg/L as K + X 100 111 mg/L as K

+

Al+++ 0.08 mg/L as Al

+++ X 10 0.80 mg/L as Al

+++

pH 6.74 N/A

Total Hardness 0.555 x 20 = 14mg/L

as CaCO3

X20 222mg/L as CaCO3

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Table 3: Total Cation Exchange Capacity

Ah Horizon B Horizon Ca++ (cmolc) 5 2.4

Mg++ (cmolc) .604 2.32

Na+(cmolc) 0 0

K+ (cmolc) 6.41 2.82

Al+++ (cmolc) .014 .008

H+ (cmolc) .00024 .00018

Total Cation Exchange(cmolc) 12.028 7.5

Table 4: Moisture Content of Field Moist Samples: Gravimetric Method

Ah Horizon B Horizon

Weight of tin 1.30 g 1.30 g

Weight of soil 20.0 g 20.0 g

Weight of soil + tin 21.3 g 21.3 g

Oven dry weight of soil + tin

19.0 g 15.8 g

Weight of Water 2.30 g 5.50 g

Percent moisture by dry weight

13.0 %

37.9 %

Percent moisture by volume

13.5 % 53.3 %

Cm water/ meter of soil

13.5 55.3

Table 5: Soil Water Holding Capacity

Ah Horizon B Horizon Volume of water used (mL) 10 10

Volume of Leachate (mL) 1.9 5.8

Volume retained by Soil (mL) 8.1 4.2

Oven dry weight of soil used (g)

15 15

% moisture by weight at 100% water holding capacity

54 % 28 %

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Table 6: Field Capacity of Disturbed Soil

Ah Horizon B Horizon Weight of tin 1.2 g 1.2g

Weight of soil 10 g 10 g

Weight of soil + tin 11.2 g 11.2 g

Oven dry weight of soil + tin 8.6 g 9.1 g

Weight of Water 2.6 g 2.1 g

Field Capacity 35.1 % 26.6 %

Table 7: Hygroscopic Water Content

Ah Horizon B Horizon Weight of tin 1.3 g 1.3 g

Weight of soil 15.9 g 15.9 g

Weight of soil + tin 17.2 g 17.2 g

Oven dry weight of soil + tin 16.8 g 17.1 g

Weight of Water 0.4 g 0.1 g

Hygroscopic moisture content 2.58 % 0.6 %

Table 8: Organic Carbon Content

Ah Horizon B Horizon Sample Weight (g) – Hydroscopic water

1.169 1.192

FeSO4 titrant Standard (mL) 10.1 10.1

FeSO4 titrant Sample (mL) 3.1 9.7

Organic Carbon (mg/g) 23.3 1.31

Organic Carbon % 2.33% 0.131%

Table 9: Mineral content percentages by horizons

Ah Horizon B Horizon

Silt Content 29.33 % 19.67 %

Sand Content 67.87 % 68.53 %

Clay Content 2.8 % 11.8 %

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Table 9: Elmsdale Average Temperature

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Average high -1.2 -1.1 3 8.4 15 20.3 23.6 23.3 18.8 12.7 6.9 1.4

Average low -10.7 -10.2 -5.8 -0.5 4.5 9.6 13.5 13.5 9.3 3.8 -0.7 -7.1

Average -6 -5.6 -1.4 4 9.8 15 18.6 18.4 14.1 8.3 3.1 -2.8

Table 10: Elmsdale Monthly Precipitation (mm)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Monthly rainfall (mm) 101 69 96 96 106 98 102 93 104 126 133 115

Monthly snowfall (cm) 55 50 41 21 3 0 0 0 0 2 14 44

Monthly precipitation

(mm) 149 114 135 118 110 98 102 93 104 129 146 155

Table 101: Aggregate size, shape and structure

Ah B

Aggregate shape Spherical aggregates Spherical Aggregates

Size 3 mm- 1 cm <1 mm

Structure Granular/crumb Granular

Table 112: Soil Water Movement

Soil Water Movement Horizon Ah B

Per Rate 2.68 m/day N/A*

Minimum Area Required for a discharge of 6.5 m3/day

2.43m2 N/A*

*Results pending

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Appendix B

Figure 2: Texture Triangle Describing Each Soil Horizon

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Figure 3: Sampling Site. Photo taken by: Alex Königseder on September 29, 2011

Figure 4: Grazing Cow. Photo taken by: Alex Königseder on September 29, 2011

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Figure 5: Sample Site Location

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Figure 6: Contour Map of Sample Site

X= Sample Site

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Figure 7: Soils Bed Rock, Milford

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Figure 8: Parent Material, Milford

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References

1. Agriculture and Agri-Food Canada. Agriculture and Agri-Food Canada Publication, (1998). The canadian

system of soil classification (third edition). Retrieved from Agriculture and Agri-Food Canada website:

http://sis.agr.gc.ca/cansis/references/1998sc_a.html

2. Globe. (2002). Bulk density protocol. Retrieved from: http://globe.gov/sda/tg/bulkden.pdf

3. H. Conley, R. Stea, Y. Brown. "Surficial Geology Of The Province Of Nova Scotia Map 92-3".1:500

000.1992. http://www.gov.ns.ca/natr/meb/download/mg/map/htm/map_1992-003.asp

4. Nova Scotia Department of Natural Resources (2011, February 8). Reading room 1: The story of glaciers in

maritime canada. Retrieved from http://www.gov.ns.ca/natr/meb/field/glacier.asp

5. Sandor, F. (2008, February 8). Soil testing. Retrieved from:

http://www.rootsofpeace.org/assets/Soil%20Testing%20Manual%20V6%20(Feb%208).pdf

6. The Canadian Biodiversity Web Site. (n.d.). Atlantic maritime. Retrieved from

http://canadianbiodiversity.mcgill.ca/english/ecozones/atlanticmaritime/atlanticmaritime.htm

7. WARD's Natural Science Establishment INC. (n.d.). Porosity and permeability of soils model. Retrieved from:

http://www.spegcs.org/attachments/committees/8/Porosity Model_Users Guide_040607.pdf