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 –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

Bulk 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

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 * 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 % WAS Total C stocks (Mg ha-1 to 40cm)

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