Land application of animal waste on irrigated fields
Schlegel, Alan, author
Stone, Loyd, author
Bond, H. Dewayne, author
Alam, Mahbub, author
Animal wastes are routinely applied to cropland to recycle nutrients, build soil quality, and increase crop productivity. This study evaluates established best management practices for land application of animal wastes on irrigated corn. Swine (effluent water from a lagoon) and cattle (solid manure from a beef feedlot) wastes have been applied annually since 1999 at rates to meet estimated corn P or N requirements along with a rate double the N requirement (2xN). Other treatments were N fertilizer (60, 120, and 180 lb N/a) and an untreated control. Corn yields were increased by application of animal wastes and N fertilizer. Over-application of cattle manure has not had a negative effect on corn yield. For swine effluent, over-application has not reduced corn yields except for 2004, when the effluent had much greater salt concentration than in previous years, which caused reduced germination and poor early growth. All animal waste and N fertilizer treatments increased soil solution NO3-N concentration (5-ft depth) compared with the untreated control. Application of animal wastes on a N requirement basis resulted in similar NO3-N concentrations as fertilizer N applied at 180 lb/a (approximate recommended rate). The 2xN application caused NO3- N concentrations to about double for both swine and cattle wastes. Application of swine effluent based on P requirement produced similar NO3-N concentrations as the 2xN rate because of the relatively low P content in the effluent.
Presented at the 2007 Central Plains irrigation conference on February 27-28 in Kearney, Nebraska.