Soil Physical Properties Related to Runoff and Erosion From Artificial Rainfall
( and planners -*of erosion-control and water-man­ agement systems need simple methods for determining the basic erodibility and runoff potential of specific soil-site complexes during the development of land-use plans for agriculture, industry, and recreation, The erosion prediction equation developed by Wischmeier et at (9, 10, 11, 12)* is serving this need at the present time for agriculture. It takes into account rainfall, geographic location, soil, slope, crop, and manage­ ment. Data was not available, how­ ever, for adequate evaluation of all of these variables. When the equation was developed, soil erodibility factor values were available for only a few soils and these were extrapolated to encompass many soils to make the erosion-prediction equation applicable over many geographic regions. Scien­ tists have done a good job here, but more quantitative data are needed. Parameters useful in predicting soil erodibility and runoff potential of cul­ tivated f a l l ow soil w e r e identified through regression analyses (4) of the soil and site physical properties with known values of rainfall, EI, runoff, and soil loss (3) . The source of erosional and runoff energy was artifical rainfall applied with a rainfall simula­ tor (5, 6, 7 ) .