Wind Erosion:
An International Symposium/Workshop

Jean L. Steiner, Harry H. Schomberg, and Paul W. Unger

Abstract

Wind erosion can cause soil degradation and crop damage on-site and air quality degradation, health problems, and property damage off-site. Crop residue cover is often managed by landowners to decrease the risk of erosion. For the Wind Erosion Prediction System (WEPS), simulating crop residue cover over time is important to simulate the quantity of soil erosion. To simulate crop residue cover, residues are predicted for three pools: standing, flat, and buried. The submodel accounts for mass change within each pool including standing residues that weaken and fall to the surface as they decompose. Daily precipitation and air temperature are used to predict decomposition of above-ground biomass and the rate that standing residues fall to the soil surface. When daily precipitation exceeds 4 mm, the moisture index for above-ground processes is considered optimum. The temperature coefficient is optimum at 32C and decreases at warmer or cooler temperatures. Decomposition of below-ground residues is based on soil temperature and water content, simulated in the hydrology submodel. The daily climate index is the minimum of the daily moisture or temperature index and is accumulated through time as decomposition days. After decomposition days are calculated, they are used to predict decomposition using a first-order decay equation, with crop-specific coefficients controlling the rate over the decomposition time. On days with high windpeed, the erosion submodel uses percent soil cover, based on standing and flat residue biomass, and stem area index, based on number, height, and diameter of standing stems per unit area to determine the resistance of the surface to erosion. The decomposition model was developed for application across diverse climate conditions and cropping systems and can be applied through WEPS to help understand and control soil erosion by wind.