documenting soil change using dynamic soil properties and ecological site descriptions
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Documenting Soil Change using Dynamic Soil Properties and Ecological Site Descriptions. Skye Wills NCSS, 2011. Soil and Ecosystem Change. Soil Change Guide Document change in soil function applicable over the entire extent of a soil series or component phase - PowerPoint PPT PresentationTRANSCRIPT
Documenting Soil Change using Dynamic Soil Properties and Ecological Site Descriptions
Skye WillsNCSS, 2011
Soil and Ecosystem Change
• Soil Change Guide– Document change in soil function applicable
over the entire extent of a soil series or component phase
– When possible, Ecological Sites and associated State and Transition Models inform study design and interpretation
– Dynamic soil properties collected concurrently with vegetation properties
Space and Time
• Some conceptual model is needed to separate the soil component being evaluated into conditions that can be compared in space– Space for time substitution allows us to
interpret change over time or caused by management system
– Statistical inference: where can results be applied
Conceptual Model
• Ecological Site with State and Transition Model
Begay DSP Project (Utah)
• Used STM to separate ecological site (R035XY215UT) and the correlated soil map component phases into conditions for comparison– Reference State -Community Phase
• 1.1 Perennial grassland/shrubland– Alternative State -Community Phase
• 4.1 and 4.2 Cheatgrass Dominated/Monoculture
Sub-state
Bul
k de
nsity
(<2m
m) g
/cm
3 :0-2
cm
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
PG-S AG
Sub-state
Db
(<2m
m) g
/cm
3 : A h
oriz
on w
ithou
t 0-2
cm
1.35
1.40
1.45
1.50
1.55
1.60
PG-S AG
Sub-state
Db
(<2m
m) g
/cm
3 : B h
oriz
on to
25
cm
1.46
1.48
1.50
1.52
1.54
1.56
1.58
1.60
PG-S AG
Bulk density
Sub-state
Org
anic
car
bon
%: 0
-2 c
m
0.3
0.4
0.5
0.6
0.7
0.8
PG-S AG
Sub-state
Org
anic
car
bon
%: A
hor
izon
with
out 0
-2 c
m
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
PG-S AG
Sub-state
Org
anic
car
bon
%: B
hor
izon
to 2
5 cm
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
PG-S AG
PG-S = perennial grass-shrub; AG = Annual grass (cheat grass) n=4
Organic carbon %
0-2
cm2
cm to
bas
e of
AB
to 2
5 cm
High and low values of reference state
Org
anic
car
bon
%: 0
-2 c
m
0.3
0.4
0.5
0.6
0.7
0.8
PG-S AG
Conceptual Model• Ecological Site with State and Transition Model• Add additional land uses – assume
these represent different states and that we understand the dynamics at work between these land uses.
MLRA 77C (TX)Amarillo DSP Project
• Chose conditions for study based on past and current land use– Rangeland – ‘Degraded’ shortgass, shrub
invaded (R077CY034TX; Shrub Dominant Community 3.1)
– Conservation Reserve Program – previously cropped, currently dominated by ungrazed introduced grasses
– Cropland –Irrigated conventionally tilled cotton
CRP – variable conditions and past management difficult to fit within STM concepts
Cropland – could conceivably be considered a separate state. However, the large energy inputs available could overwhelm any subtle ecological dynamics in the site.
Amarillo: Wet Aggregate Stability
Mean Weight
Diameter
Standard ErrorMean Weight
Diameter
Mean Proportion > 0.25 mm
Standard Error
Proportion > 0.25 mm
mm mm % %
Shrub (3.1) 4.81a* 0.25 0.84a 0.04
CRP 2.73b 0.22 0.55b 0.03
Crop 0.43c 0.22 0.14c 0.03
* Means with same letter are not significantly different (P=0.05)Ted Zobeck, personal communication 4/20/11
Conceptual Model• Ecological Site with State and Transition Model• Add additional land uses – assume these represent
different states and that we understand the dynamics at work between these land uses.
• Chose to evaluate management systems within one land use– Pasture– Forest – Crop
Idaho Threebear project
• Chose to evaluate management conditions in forest land– Mature forest– Clear-cut and planted forest
Threebear Results
MLRA 106 (NE and KS): Kennebec Soil
• Chose to evaluate management systems within cropland– Generally, corn/soybean rotation with
• Conventional tillage system• No-till system• “organic” system
– While this sounds like a straightforward comparison there are many variations of each of these management systems. Deciding what to compare and what to include in each was a major difficulty.
Kennebec Results%
WA
S
Tot
al C
sto
cks
(Mg
ha-1
to 4
0cm
)
Using ESDs to Interpret Soil Change
• An ESD and particularly the state and transition model provide context for making management recommendations and interpretations
• It also segments a soil map unit component phase into conditions relevant for management– That is – this component with the same
community phase present will likely have the same properties and respond to management in the same way
Using ESDs to Interpret Soil Change
• Begay Project – the STM supplies contextual information about the ecological dynamics of the site
• Amarillo Project – While the STM provides information about range and CRP land – it doesn’t tell us how broadly we can apply the results from the cropland or what processes are important for maintaining or restoring ecosystem function
Ongoing Projects• MLRA 133A (GA)Tifton – Longleaf
Pine/Wiregrass vs. Pasture – Data collection being done concurrently with
ecological site data collection– Presents challenges …………but should allow
us to interpret and infer ecosystem change• MLRA 80A (OK and KS) Kirkland –
Claypan Prairie Rangeland vs. Cropland– Conventional and no-till management
systems within cropland land use will be sampled
Acknowledgements• Arlene Tugel• Cindy Stiles• Ted Zobeck• Laurie Kiniry• Craig Bird• Gerald Crenwelgie
• Dave Kohake• Bruce Evans• Judy Ward• Brian Gardner