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Abstract

Guo, M., N. Tongtavee, and M. Labreveux. 2009. Integrated management practices for reducing nutrient runoff losses from animal manure-fertilized cropland. JEMREST 6:00-00

DOI: 10.4029/2009jemrest6no16

Many management practices such as filtering buffers and soil incorporation have been employed to reduce nutrient runoff losses from land-applied animal manure. The federal Clean Water Act requires a minimum 30-m setback between the manure application area and down-gradient surface waters; alternative conservation practices or field specific conditions have to provide nutrient reductions equivalent to or better than would be achieved by the 30-m setback. This study was to investigate the interactive effect of common best management practices on reducing nutrient runoff losses from manure-fertilized cropland, and to determine the necessary widths of setbacks integrated with different management practices for controlling nutrient runoff losses. Field plot experiments were conducted in central Delaware with poultry litter applied to a soybean field at 18.9 ton ha^-1. Nitrogen and phosphorus losses in runoff water at varied setback widths from plots (45 m × 15 m) under the management practices “surface manure application”, “manure soil incorporation”, “winter cover crop”, and “winter cover crop plus manure soil incorporation” were quantified. With litter surface application, runoff losses of N and P from the plots were 1.86 and 0.49 kg ha^-1, respectively; the losses were reduced to 0.98 to 0.18 kg ha^-1, respectively, after the filtering of a 30-m setback. Relative to “surface application”, “soil incorporation” and “winter cover crop” effectively reduced nutrient runoff losses. Employment of either of the best management practices would reduce the setback requirement to 15 m; if both were employed, the setback requirement could be further reduced to 10 m.