Erosion Potential of a Torrertic Paleustoll after Converting Conservation Reserve Program Grassland to Cropland

Abstract

Extensive cropland areas were covered by the Conservation Reserve Program (CRP) in the semiarid southern Great Plains. Because soils were highly erodible, would erosion again become a problem when CRP land was converted to cropland? The erosion potential due to tillage methods used to convert CRP grassland to cropland was determined on Pullman clay loam (Torrertic Paleustoll). Tillage methods were no‐, sweep, disk, and moldboard + disk tillage with CRP grass retained or removed (mowing and baling), and grass burning followed by sweep or disk tillage. Wind erosion potential was based on percentage of >0.84‐mm diam. and mean weight diameter (MWD) of dry aggregates at 2 to 3 yr after converting to cropland. Water erosion potential was based on MWD and percentage of <0.25‐mm water‐stable aggregates, and water stability of 1‐ to 2‐mm aggregates at crop planting and harvest. Few differences due to tillage methods were significant. For dry aggregates, more than 60% were >0.84‐mm diam. and MWD was >10 mm with all tillage methods, indicating a low wind erosion potential. Wet aggregate stability and MWD values at some sampling times indicated water erosion could occur. Although erosion potential was low, continued use of residue‐incorporating tillage could lead to greater potentials. Because of initially low potentials, CRP land on Pullman and similar soils could be converted to cropland by any tillage method. Then, a conservation tillage system (e.g., no‐tillage) could be implemented before erosion by wind or water became a serious problem.