ABSTRACT:
Phosphorus (P) is an important input for economic crop and livestock production systems. Excessive losses of P from agricultural systems to surface waters can accelerate eutrophication and degrade water quality. This paper reviews the behavior of P in agricultural soils and discusses the transport of P from land to water. The forms, measurement, and sorption processes of P in both soil and water are discussed. Soil test P, the most common soil P analysis, is described relative to other forms of soil P and its use for agricultural and environmental purposes is explained. Loss of soil P to water can occur in particulate forms with eroded surface soil and in soluble forms in runoff, soil interflow, and deep leaching. This paper discusses the relative importance of each transport pathway as affected by soil type and management. Soil P dynamics and water quality risks associated with fertilizer and manure application are illustrated with several examples. Finally, the paper reviews management practices that can effectively reduce the loss of agricultural P to surface waters.
Footnotes
Neil C. Hansen is an assistant professor of soil science in the Department of Soil, Water, and Climate at the University of Minnesota, St. Paul, Minnesota; Tommy C. Daniel is a professor of agronomy in the Department of Agronomy at the University of Arkansas in Fayetteville, Arkansas; Andrew N. Sharpley is a soil scientist at the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) Pasture Systems and Watershed Management Research Laboratory in University Park, Pennsylvania; and Jerrell L. Lemunyon is a nutrient and pest specialist at the USDA-Natural Resources Conservation Service (NRCS) in Fort Worth, Texas.
- Copyright 2002 by the Soil and Water Conservation Society
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