An Analysis of Short‐ and Long‐Term Impacts of Several Soil‐Loss Control Measures

Two large‐scale interregional and national linear‐programming models are used to examine the impacts on agricultural production, resource use, and soil loss of several soil‐loss control measures. The short‐run model (1985) incorporates no productivity loss due to soil erosion, while the long‐run model (2000) does. Five short‐run and six long‐run alternatives are analyzed. These alternatives include reducing soil losses by fixed percentage values or to a fixed multiple of the soil‐loss tolerance levels ( 2T in the short‐run and T in the long‐run model). The base solutions with no targeted soil‐loss reductions project gross soil losses of 2.8 and 1.1 billion t for 1985 and 2000, respectively. By limiting soil losses to 2T and T , the soil losses are reduced to 1.4 and 0.6 million t, respectively. Many more hectares are placed in conservation practices and reduced‐tillage methods in the long‐run when compared with the short‐run model. Soil‐conserving practices such as contours, strip cropping, and terracing are not used in the short run, indicating that conservation practices will not be utilized under a short planning horizon and an objective of profit maximization. The private economic benefits for conserving soil in the short run are less than the costs in doing so. When yield impacts from soil erosion are considered as in the long‐term solution, it is profitable to use these conservation practices.