Phosphorus restrictions for land application of biosolids: Current status and future trends

• Published in: Journal of environmental quality Vol. 32; no. 6; pp. 1955 - 1964
• Main Authors: Shober, A.L, Sims, J.T
• Format: Journal Article
• Language: English
• Published: Madison, WI Crop Science Society of America 01.11.2003; American Society of Agronomy
• Subjects: Agricultural land; Agriculture; Agriculture - legislation & jurisprudence; Agronomic crops; Agronomy. Soil science and plant productions; Animal manures; Applied sciences; Biological and medical sciences; Biosolids; chemistry; Crop yield; Environmental assessment; environmental impact; environmental law; Environmental Monitoring; Environmental risk; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Government Regulation; Humans; land application; legislation & jurisprudence; Literature reviews; nonpoint source pollution; nutrient availability; nutrient content; nutrient management; Other industrial wastes. Sewage sludge; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; phosphorus; Phosphorus - chemistry; Pollution; Risk assessment; Sewage; Sewage - chemistry; Sewage - legislation & jurisprudence; Sewage sludge; Soil; Soil amendment; Soil and water pollution; soil fertility; soil pollution; Soil science; Soil testing; Soil-plant relationships. Soil fertility. Fertilization. Amendments; United States; United States Environmental Protection Agency; Wastes; Water Pollutants, Chemical; Water quality; United States; North America; America; Pollution prevention; Phosphorus; Agricultural soil; Review; Balanced fertilization; Sewage sludge; Amendment; Upgrading; Maximum permissible concentration; Risk assessment; Environment impact; Waste reuse; Nutrient; Water pollution; Regulation
• DOI: 10.2134/jeq2003.1955
• ISSN: 0047-2425

The application at biosolids (sewage sludge) to agricultural soils provides P in excess of crop needs when applied to meet the N needs of most agronomic crops. These overapplications can result in the buildup of P in soils to values well above those needed for optimum crop yields and also may increase risk of P losses to surface and ground waters. Because of concerns regarding the influence of P on water quality in the USA, many state and federal agencies now recommend or require P-based nutrient management plans for animal manures. Similar actions are now under consideration for the land application of biosolids. We reviewed the literature on this subject and conducted a national survey to determine if states had restrictions on P levels in biosolids-amended soils. The literature review indicates that while the current N-based approach to biosolids management does result in increases of soil P, some properties of biosolids may mitigate the environmental risk to water quality associated with land application of P in biosolids. Results of the survey showed that 24 states have regulations or guidelines that can be imposed to restrict land application of biosolids based on P. Many of these states use numerical thresholds for P in biosolids-amended soils that are based on soil test phosphorus (STP) values that are much greater than the values considered to be agronomically beneficial. We suggest there is the need for a comprehensive environmental risk assessment of biosolids P. If risk assessment suggests the need for regulation of biosolids application, we suggest regulations be based on the P Site Index (PSI), which is the method being used by most states for animal manure management.