This paper studies broiler litter utilization in an agricultural watershed using a Geographical Information System (GIS) and an optimization model. An optimization model is developed which selects broiler liter management practices that maximize total net returns to land and management and estimates economic value of litter as a fertilizer substitute for an agricultural watershed experiencing rapid growth in broiler production. Land application rates are determined based on crop nutrient requirements, fertilizer source, and litter cleanout schedule. Results indicate that litter as a fertilizer is economically favored over commercial fertilizer. Land area required for current litter application does not exceed suitable land application areas after excluding sensitive areas such as streams, roads and sink holes. However, litter from further growth in broder production will soon reach the maximum capacity of suitable land areas in the watershed. Nutrients in current litter amounts do not exceed crop nutrient requirements, but would equal crop requirements if broiler production is doubled (tripled) and liner application rates are determined on a phosphate (nitrogen or potash) basis. GIS is a powerful analytical tool for analyzing economic and environmental problems. Litter is an inexpensive substitute for commercial fertilizer and its value varies with the nutrient basis used to application rates, litter cleanout schedule and fitter availability.
