Submitted to: Water Practice
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2007
Publication Date: 10/1/2007
Citation: Armstrong, S., Smith, D.R. 2007. Strategies to reduce nutrient losses from land applied animal manure. Water Practice. 1(4). doi:10.2175/193317707X243364. Interpretive Summary: Over the last several decades, the number of animal feeding operations has decreased, while the number of animals raised nationally has remained fairly constant. This has been due to the incorporation of confined animal feeding operations as a major component of the animal rearing industry. These larger farms, sometimes on relatively small plots of land, have led to the concentration of manure nutrients in specific geographic regions of the country. As a result, responsible animal producers use many practices to minimize their impacts on water quality. These practices include: 1) dietary modification to reduce the amount of phosphorus fed; 2) adding chemical amendments to precipitate nutrients; 3) methods of incorporating manure into the soil, or preparing the soil for manure application; 4) using buffer strips to minimize the direct impacts of manure applications on adjacent water bodies; and 5) the use of tools, such as the phosphorus index, to optimize manure applications for both environmental and agronomic concerns. In this manuscript, we present a review of these practices used by animal producers. The impact of this manuscript is to present the practices used by the animal agriculture industry to the municipal biosolids community.
Technical Abstract: Continued land application of animal manure to agriculture fields result in elevated soil N and P concentrations that exceed crop requirements and are lost to surface water bodies. Losses of N and P lead to accelerated eutrophication, seeing that in most freshwater ecosystems P is the most limited nutrient for algal growth and N is an essential element for plant and algal growth. Several strategies can be used by landowners and animal producers to minimize losses of N and P from agricultural fields, including: dietary modification; manure amendments; manure application method and soil preparation; buffer strips; and using the P index to determine the manure application rates and risks. Researchers have demonstrated that both diet modifications and aluminum amendments could reduce soluble P in manure and runoff by 60%, while manure injection reduced runoff total P by 92 %. The employment of these and other strategies by responsible landowners is critical in reducing the vulnerability of N and P to losses via runoff following animal manure application. The impact of this manuscript is to inform a new audience about the efforts by responsible managers of confined animal feeding operations to reduce potential losses nutrients to surface waters.