Predicting soil wind erosion potential under different corn residue management scenarios in the central Great Plains

Various models and simplified equations are available to predict wind erosion potential. However, their performance can be often site-specific, depending on soil characteristics and agronomic practices, warranting site-specific model validations. Thus, in this study, we 1) validated the wind erodible fraction (WEF) predictive equations by Fryrear et al. (1994) and Lopez et al. (2007) and 2) estimated the total soil loss with the Single-event Wind Erosion Evaluation Program (SWEEP) using 3-yr measured data from six experiments located across a precipitation gradient in the central Great Plains. Each site had three corn (Zea mays L.) residue removal treatments: control (no removal), grazed, and baled. The measured and predicted WEF were significantly correlated. While the Fryrear et al. (1994) equation performed better than the Lopez et al. (2007) equation, it underestimated WEF with 59% uncertainty across site-years. To reduce this underestimation and uncertainty, we developed a new statistical equation (WEF% = 84.3 + 2.64 x % silt-0.30 x % clay-7.43 x % organic matter-0.15 x % residue cover; r(2) = 0.56). The predictive ability of the new equation was, however, no better than that of the existing predictive equations, suggesting the need for further refinement of WEF equations for the region. Simulated total soil loss by wind using the SWEEP model indicated that corn residue baling may increase soil loss if residue cover drops below 20% in the study region. Overall, the existing WEF equations could under- or over-estimate WEF based on site-specific residue management, warranting further model refinement and site-specific validation, whereas the SWEEP estimated soil loss corroborates the critical importance of maintaining sufficient residue cover (> 20%) to reduce wind erosion.