Walter H. Wischmeier developed the Universal Soil Loss Equation, first published in 1958 (USDA Agriculture Handbook 282). Over the next 20 years he refined and improved the USLE and published the results of his efforts in 1978 in Agriculture Handbook 537, which is still a standard reference. The USLE is widely used for land management plannning worldwide and is regarded--according to the International Soil and Water Conservation Society--as "the primary tool of conservationalists for planning purposes."
The USLE, pioneering use of computers for agricultural problems, resulted from analyses of more than 11,000 plot-years of research data from 47 locations in 24 states (The USLE Database). The equation provides techniques for numerically evaluating effects of climate, soil properties, topography, crop-productivity level, time and method of seeding, crop sequence, residue management, special conservation practices, and other pertinent variables that effect soil erosion. It is a required element in farm and ranch plans used to qualify for USDA assistance programs; it is an invaluable tool for natural resource inventories carried out in the United States; it has been the basis of economic analyses related to agriculture; and it has been an important element in analyses dealing with assesment and control of surface water quality.
The USLE has provided an invaluable tool for natural resource inventorying of the united States. The technology has been used to analyze the erosion effects on crop productivity and has been the basis of economic analyses such as those conducted by the Center for Agricultural Rural Development at Iowa State University (this work has been the basis of the USDA's Resource Conservation Act mandates).