Variation In Computing The Length Factor In The Universal Soil Loss Equation

Ernest Tollner
2008 Annual Conference & Exposition Proceedings   unpublished
Ernest W. Tollner is a native of Maysville, KY and received his BS and MS degrees in agricultural engineering at the University of Kentucky. He did his doctorate at Auburn. His graduate work was concerned with computer modeling erosion control, water resource development and animal waste management. This work provided the foundation for extension into composting, bioconversion and imaging research. Dr. Tollner was among the first to use topographic scanning for charactering soils, food products
more » ... oils, food products and logs. Research over the past 25 years at the University of Georgia has resulted in over 100 publications and 3 patents. Abstract The universal soil loss equation, A = R*K*L*S*C*P, estimates average annual soil loss A based on rainfall (R), soil factor (K), length factor (L), slope (S), effective cover factor C, and a practice factor P. In teaching the use of the relationship, students can find values of R on maps, soil factor in tables based on a soil classification readily available in soil surveys, slope S may be estimated from the topographic map of the site., the cover factor C may be ascertained based on a specified crop rotation and the erosion handbook and the practice factor P may be determined from the erosion handbook for specified conservation practices such as terracing, contouring, etc. One source of variation in estimates is to arrive at meaningful slope length L. The erosion handbook suggests that one look for the length of the steepest segments of slope in the typical field of variable slope but leaves to judgment the actual quantification. The paper will report on the variation in techniques that students and professionals learn and use when asked to implement this procedure. A new approach for making a quantitative estimate of the length factor will be presented and compared with research data.
doi:10.18260/1-2--3133 fatcat:cnqozjh6djcovoj6rll7rgohwa