ABSTRACT:
The U.S. Department of Agriculture developed a sophisticated physical process model to summate the soil-climate-plant-management processes in agricultural production and to estimate the impact of soil erosion on resource productivity and fertilizer requirements for the 1985 Resources Conservation Act appraisal. Estimates from this model, the erosion productivity impact calculator (EPIC), show that if cropping patterns and the mix of management, tillage, and conservation practices inventoried in the 1982 National Resources Innovatory are continued for 100 years, sheet and rill erosion and wind erosion will exceed the erosion tolerance (T) on 127 million acres and 64 million acres, respectively. This rate of soil loss will reduce productivity in the 100th year by an estimated 2.3 percent—the equivalent to taking 7.4 million acres of cropland out of production. Annual fertility requirements are estimated to increase by 798, 672, and 10,920 million pounds of nitrogen, phosphate, and lime, respectively. The present value of this 100-year national loss is about $22 billion.
Footnotes
John W. Putman, until his retirement, was a project leader with the Natural Resource Economics Division, Economic Research Service, U. S. Department of Agriculture, Temple, Texas 76503. Jimmy R. Williams is a hydraulic engineer with the Agricultural Research Service, USDA, Temple, Texas 76503. David Sawyer is an agricultural economist with the Soil Conservation Service, USDA. Washington, D. C. 20013.
- Copyright 1988 by the Soil and Water Conservation Society
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