Cropping-Management Factor Evaluations for a Universal Soil-Loss Equation
1960
Wischmeier, Walter H.
About 8,000 plot-years of soil-loss and related data assembled from 21 states were analyzed to evaluate influences of vegetal growth, crop sequence, tillage practices, fertility, and residue management on erosion of soil by rainfall. Specific-crop data were grouped according to relatively homogeneous intervals such as the respective rough fallow, seedbed, establishment, growing crop, and residue periods. For each such period, measured soil losses under specific combinations of crop sequence and management were compared with corresponding losses from bare fallow. Not only canopy protection, but the residual effects of prior cropping and management as well, differed significantly for the respective crop-stage periods. Soil losses for each crop-stage period under various sequences and management levels are presented in tabular form as percentages of losses from fallow under identical rainfall. The table was designed for use with rainfall erosion index maps and monthly distribution curves computed from localized rainfall records as discussed in “A Rainfall Erosion Index for a Universal Soil-Loss Equation” (Soil Sci. Soc. Am. Proc. 23:246–249. 1959). Combined with the erosion index and other factors comprising the soil-loss equation, the tabulated values will help to provide valuable guides for conservation farm planning adapted to the local rainfall pattern.
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