An inexact system programming for agricultural land utilization based on nonpoint source pollution control in Wuchuang watershed

The challenge of efficiently controlling agricultural non-point source pollution confronts many difficulties when only engineering and technical methods are implemented, regardless of the outstanding conflict between economic development and environment protection in watersheds in China. An interval numbers optimization model was adopted to study the relationship between land use and agricultural nutrient pollution control at the lowest cost in Wuchuan Catchment of upstream Xixi River in the Jiulong watershed, Fujian Province. That the land layout at present consists of ten types of land use of agricultural production processes results in more agricultural non-point source pollution. To reduce the non-point source pollution, seven management practices, which occupied respectively seven different types of land utilization, were established with the help of AGNPS5.0 according to the features of the catchment. Both land utilization patterns of agricultural processes and land use patterns of pollution control practices to be adopted were analyzed by this system optimization model. Results indicated that the current land utilization patterns of the catchment need to be improved, and that farming habits and management practices should also be ameliorated. To achieve a reasonable and applicable program, the decision-makers can integrate the solutions of the model with their experience and other relevant information. The generated program can guarantee a maximized economic output within the limit of non-point source pollution contribution. The inexact system programming model supplies a number interval that considers the complexity of agricultural non-point source pollution and the uncertainty during the decision-making processes.