Farmers and manure management: a critical analysis
Utilization of animal manure as a soil resource is a concept that was practiced widely before the advent of commercially available fertilizers and the increase in the size of farm and livestock operations. Throughout the world there is an increasing concern about the generation of animal manure in volumes that could potentially pose environmental problems and inefficient use in agricultural systems. There is an increasing social dilemma over the use of manure because of the odor problems and costs of application and handling of manure compared to commercial fertilizers. These are only a few of the emerging concerns about the use of manure. Manure is often considered a waste and its decomposition is referred to as waste disposal rather than resource utilization. This attitude toward manure has led to much of the current misunderstanding of how we could use this resource to supply crop nutrients and increase soil organic matter. If one looks through the history of agricultural research, it is easy to see that our current understanding of manure is based on research conducted in the late 1960s with a few studies in the 1970s. Much of that research focused on the supplying of crop nutrients and not on the environmental consequences of surface runoff of phosphorus or leaching of excess nitrate-nitrogen through the root zone. We have also changed the primary tillage practices, and much of the manure application is onto land in which there is a requirement for a crop residue cover. This residue cover requirement limits the incorporation of manure and there is little equipment technology available to help the producer through these problems. We have a research base on which to draw initial answers about the effective use of manure; however, these have not been summarized in any treatise for use by a range of audiences. In 1994 a workshop was held on the Effective Use of Manure as a Soil Resource as part of the National Soil Tilth Laboratory’s series on Long-Term Soil Management. The workshop was held with the goal of bringing together researchers who had developed much of the current knowledge base on manure use and handling and of drawing inferences from their research and understanding of the problem to provide a base that could be used to develop solutions for the problems of today and tomorrow. The chapters contained within this volume include one on the attitudes of farmers about the use of manure by Pete Nowak and his co-workers and one on the economics issues surrounding manure usage by Lynn Forster. We are fortunate to have their expertise available to us as we try to develop new programs for manure utilization. The chapters on swine, dairy, and poultry manure show examples of current problems and the limitations of technology specific to a given livestock industry. These authors provide a basis for improved understanding of manure generation and utilization as a soil resource. Manure is often considered to be a cropland resource; however, application to rangeland and grass pasture is often practiced over a wider range of climates and manure types. Use of manure on grazing lands helps to define the potential uses on this type of system. Environmental concerns from the use of manure are often associated with ground and surface water quality. This chapter details the impacts of nitrate-nitrogen and phosphorus movement from different manure sources and the potential environmental impacts. To help develop an improved management tool for manure, the final chapter describes the use of system engineering principles to help develop manure management and utilization scenarios. This volume is intended to help promote interest in the use of manure; however, it also captures our current knowledge base so that we can develop effective research programs that build upon this existing knowledge base. It is imperative that we continue to develop solutions that can be readily adopted by the user community and that when adopted, instill confidence in the user and society that the agricultural community is interested in efficient production, a high quality environment, and being good neighbors. It is our desire that this book serve as an initial step in that process.
Ann Arbor Press
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