1a. Objectives (from AD-416):
In coordination with the corn stover removal field trials and residue removal tool development, support the development and implementation of modeling methods for assessing the soil compaction impact of agricultural residue removal on continued productivity and soil health.
1b. Approach (from AD-416):
Soil compaction has been identified as one of six limiting factors which collectively define the sustainability of agricultural residue removal for bioenergy production. The soil compaction limiting factor is challenging to calculate quantitatively and at the scale being modeled through the Residue Removal Tool. The impact of soil compaction results from complex interactions of many independent factors. There currently is no model for soil compaction that exists in the mold of the other limiting factor models. Subsequently, the goal of the Residue Removal Tool development team is to implement numerical relationships that consider the soil compaction limiting factor as effectively as possible at the field and sub-field scale. The scope of this project is guiding the development and implementation of those numerical methods within the tool framework. The following list represents the tasks that need to be completed to effectively consider soil compaction impacts within the Residue Removal Tool framework: 1) Review existing models and numerical methods for estimating soil compaction on agricultural lands; 2) Determine additional input data, beyond the current dataset utilized in the tool that will be required to model soil compaction; 3) Build the data and computational method map for soil compaction modeling within the tool framework; 4) Complete the integration of the soil compaction modeling methods within the tool. Work will begin reviewing existing models and numerical methods for soil compaction immediately upon funding receipt. The primary deliverable for this task will be a white paper representing the viable approaches for calculating soil compaction impacts from residue removal within the current Residue Removal Tool schemas. The white paper will begin the work toward understanding the additional input data that will be needed within the tool to perform the soil compaction calculations. This effort will continue into year two of funding, and lead to the development of the data and computational method map as outlined in task three.
3. Progress Report:
A white paper is being prepared identifying the major factors controlling soil compaction if biomass is removed from agricultural fields for energy production. The paper identifies the Least Limiting Water Range as an appropriate means for evaluating soil improvement or degradation caused by changes in soil organic matter. Changes in soil physical properties as well as the additional compaction forces induced by the residue removal process are considered in evaluating soil compaction effects on soil productivity.