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Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Watershed Management to Meet Water Quality Standards and Emerging TMDL (Total Maximum Daily Load) Proceedings of the Third Conference 5-9 March 2005 (Atlanta, Georgia USA) Publication Date 5 March 2005  701P0105.(doi:10.13031/2013.18066)
Authors:   K. O. Keplinger
Keywords:   economics, optimization, linear programming, broiler litter, nutrients, phosphorus, alum, phytase

Several regions of the US have experienced rapidly increasing livestock densities in response to changing technological and economic factors. This has sometimes led to water quality concerns as ever-greater amounts of manure must be disposed of on existing land resources. This paper investigates the costs and environmental effectiveness of two phosphorus best management practices (BMPs) for broiler operations: alum amendment of broiler litter (alum) and phytase addition to broiler feed (phytase). BMP scenarios are simulated under two environmental policy scenarios, a low agronomic rate scenario and a high agronomic rate scenario. Simulations are accomplished utilizing a cost minimizing manure transportation and application model. The costs and environmental effectiveness of BMPs are evaluated for a range of broiler litter availability, where greater litter availability implies higher geographical concentrations of broiler operations. Results suggest that excess applications of litter phosphorus are reduced for the alum and phytase BMPs under the high agronomic rate policy scenario. Litter value, however, is also reduced for both BMPs under both the high and low rate policy scenarios. Reduced transportation expense is more than offset by the reduced value of the litter as a result of reducing the phosphorus content, since litter phosphorus can often substitute for commercial fertilizer phosphorus. Where litter phosphorus is over-applied, however, alum and phytase can reduce or eliminate excess phosphorus application while, in some situations, leaving litter value unchanged.

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