MANURE MANAGEMENT AND NUTRIENT LOSS UNDER WINTER CONDITIONS - A LITERATURE REVIEW

Authors: SRINIVASAN, M - PENN STATE UNIV; Bryant, Ray; Callahan, Michael

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/2006
Publication Date: 7/20/2006
Citation: Srinivasan, M.S., Bryant, R.B., Callahan, M.P. 2006. Manure management and nutrient loss under winter conditions - a literature review. Journal of Soil and Water Conservation. 61(4):200-209.

Interpretive Summary: Nutrient transport from land to water bodies result in undesirable water quality problems. Though winter application of manure is perceived to be detrimental to soil and water qualities, it is widely practiced. Manure management guidelines for winter periods largely rely on applicators' common-sense. An extensive literature review was undertaken to assess the state-of-the-science and identify immediate research needs in relation to winter manure management. Literature survey indicated that there is a lack of understanding of manure transport processes under winter conditions.

Technical Abstract: Excessive losses of nitrogen (N) and phosphorus (P) from agricultural fields have been identified as a major source of these elements that can have detrimental impacts on environmental quality. Nutrient management guidelines, such as the P Index, are designed to minimize the risk of nutrient loss with minimal disruption to the whole farm operation. Restricting winter spreading of manure as a means of reducing nutrient loss is a contentious issue in the northern-tier states of the United States and almost all provinces of Canada. Producers have strong opinions with regard to the merits of winter spreading and arguments against the alternative practice of manure storage. In the context of the rationale in favor of winter spreading and current guidelines for winter manure management, the purpose of this paper is to review the results of scientific studies relevant to the issue of winter spreading of manure, and identify needs for additional research in this area. Collectively, these studies illustrate the complexity of N and P dynamics in response to a wide spectrum of winter conditions, but do shed some light on soil-manure-snow interactions with respect to cropping system effects on runoff, manure mulching effects, manure properties, and differences due to manure placement relative to a snow pack and timing of application. However, process-level understanding of manure-snow-soil interaction during winter periods is still lacking, and critical variables that control hydrologic and transport processes under winter conditions have not been fully identified. Extensive watershed-scale observations in combination with plot and field scale experiments focused on specific processes should yield sufficient knowledge and data to develop empirical models, which are useful first steps in developing more detailed understanding of manure management and associated nutrient loss under winter conditions.