Environmental Soil Testing for Phosphorus

TLDR: The roles soil testing programs can play in the development of nutrient management strategies, such as the P index, that are needed to minimize nonpoint source pollution by soil P are discussed.

Abstract: Many soils in the USA have extremely high soil test P levels from long-term fertilization and manuring. Sediment-bound and soluble P in runoff from these soils may contribute to eutrophication of surface waters. A field rating system, the «P index,» has been developed to assess the potential for soil P to contribute to nonpoint source pollution. A critical component in this index is soil test P. The primary objective of this paper is to discuss the roles soil testing programs can play in the development of nutrient management strategies, such as the P index, that are needed to minimize nonpoint source pollution by soil P. A survey of soil testing labs participating in four regional soil testing committees (North Central, Northeast, Mid-Atlantic, Southeast) was conducted in 1991-1992 to determine current approaches to soil P testing, the percentage of soils testing in the high or excessive range, and major concerns with high P soils [...]