On-Farm Agro-Economic Effects of Fertilizing Cropland with Poultry Litter

The profitability of using poultry litter as a fertilizer and soil amendment in cultivated agriculture was evaluated with the hopes of determining an economically optimal fertilization strategy. The traditional commercial ( inorganic) fertilizer practice was compared with several hybrid litter and commercial N fertilization alternatives in terms of on-farm agro-economic effects. Six years of land management, crop yield, crop price, and fertilizer cost data were collected from 6 field sites in central Texas and utilized for economic analysis. Varying litter and inorganic fertilizer combinations resulted in minimal differences in corn and wheat yields; however, total fertilizer costs increased significantly as litter application rate increased ( and commercial fertilizer rate decreased) in spite of dramatic cost increases for commercial fertilizer. The greatest average annual profits were determined to occur at the 1 and 2 tons/acre (ac) litter rates with 7 to 14% profit reductions for the commercial fertilizer-only treatment and the 3 tons/ac litter treatment. At litter rates greater than 3 tons/ac, diminishing returns were observed as fertilizer costs increased with no compensating greater yields to provide offsetting revenues. It is important to note that this economically optimal annual litter rate of 1 to 2 tons/ac is also environmentally optimal according to nutrient runoff and soil nutrient data collected on-site. These results provide the scientific basis to support the use of litter as a cost-effective, environmentally friendly fertilizer alternative in this and similar regions.