The fate and transport of phosphorus in agricultural systems

TLDR

Phosphorus is a critical input for crop and livestock production, but its excessive loss from soils to surface waters—via particulate erosion and soluble runoff—can accelerate eutrophication and degrade water quality. This review examines phosphorus behavior in soils, transport pathways to water, and management practices that can reduce agricultural phosphorus loss. The authors discuss P forms, measurement techniques, sorption processes, soil test P, and the relative importance of transport pathways influenced by soil type and management. Examples illustrate how fertilizer and manure application influence soil P dynamics and pose water quality risks.

Abstract

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.