Soil Erosion and Organic Matter Variations for Central Great Plains Cropping Systems under Residue Removal

Abstract

Removal of crop residues for bioenergy, feedstock, or other purposes should be done with caution to avoid excessive soil erosion or loss of soil organic matter (SOM). This study examined average annual changes in soil erosion from rainfall and wind forces and trends in soil organic matter as a function of commodity and/or bioenergy-based crop rotations, yield variations, and different field management practices, including residue removal across all land capability class (LCC) I to VIII soils in selected areas of the U.S. Central Great Plains (CGP). Specifically, comparisons were made between various rotations including corn, winter wheat, sorghum, cotton, fallow, and canola, subject to reduced tillage and no-till management practices. The purpose was to assess cropping options, field management, and soil sustainability to provide a geospatial assessment for use in soil conservation planning and possible bioenergy resource assessments in the CGP. Soil erosion and SOM (proxied by a soil conditioning index, SCI) were analyzed on individual soil map unit components using the RUSLE2 and WEPS models. Results were grouped by LCC and organized with respect to three different spatial resolutions: field scale (individual soil type), field scale aggregated to county level, and field scale aggregated to regional level. Analyses indicate variation in soil erosion and SCI trends as a function of crop type, rotation, and field management practices across different soil types within a single county and at the regional level. Considerable variation in removable residue amounts also occurred across different rotations, especially with respect to crop type, rotation, soil type, and tillage. Results obtained in this study should help advance the overall knowledge base of both public and private-focused commodity and bioenergy crop production agriculture and soil sustainability by providing small informational resolution (i.e., soil type) data on soil erosion and health trends that could have a pronounced effect on producer economics and long-term land sustainability.