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 When possible Ecological Sites and associated State and Transition Models inform study design and interpretation ID: 760629
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Slide1
Documenting Soil Change using Dynamic Soil Properties and Ecological Site Descriptions
Skye Wills
NCSS, 2011
Slide2Soil 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
Slide3Space 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
Slide4Conceptual Model
Ecological Site with State and Transition Model
Slide5Begay 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
Slide6Slide7Bulk density
PG-S
= perennial
grass-shrub;
AG = Annual grass (cheat grass)
n=4
Organic carbon %
0-2 cm
2 cm to base of A
B to 25 cm
High and low values of reference state
Slide8Slide9Conceptual 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.
Slide10MLRA 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
Slide11CRP – 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.
Slide12Amarillo: Wet Aggregate Stability
Mean Weight DiameterStandard ErrorMean Weight DiameterMean Proportion > 0.25 mmStandard Error Proportion > 0.25 mmmmmm%%Shrub (3.1)4.81a*0.250.84a0.04CRP2.73b0.220.55b0.03Crop0.43c0.220.14c0.03
* Means with same letter are not significantly different (P=0.05)
Ted
Zobeck
, personal communication 4/20/11
Slide13Conceptual 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
Slide14Idaho Threebear project
Chose to evaluate management conditions in forest land
Mature
forest
Clear-cut and planted forest
Slide15Threebear Results
Slide16MLRA 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
% WAS
Total C stocks (Mg ha-1 to 40cm)
Slide18Using 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
Slide19Using 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
Slide20Ongoing 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
Slide21Acknowledgements
Arlene TugelCindy StilesTed ZobeckLaurie KiniryCraig BirdGerald Crenwelgie
Dave Kohake
Bruce Evans
Judy Ward
Brian Gardner