Optimal Control of Nitrogen Losses from Land Disposal Areas

The land disposal alternative is not free from water pollution potential. Nitrogen losses from percolation and runoff may contaminate water supplies and contribute to the eutrophication of aquatic systems. A general model of the soil nitrogen budget has been developed for the purpose of comparing alternative strategies for controlling nitrogen leaching losses from a cropped land disposal area. The model is based on monthly inventory equations for both inorganic and organic soil nitrogen and includes the processes of plant nitrogen uptake, mineralization of organic nitrogen, and leaching. The model was tested using nitrogen budget data from several New York corn production field studies. The model was linearized and linear programming was used to find monthly disposal schedules that maximize annual returns from a sewage sludge disposal system subject to constraints on nitrogen leaching losses.