Effect of Long-Term Annual Application of Biosolids on Soil Properties, Phosphorus, and Metals

• Published in: Soil Science Society of America journal Vol. 72; no. 1; pp. 73 - 82
• Main Authors: Schroder, J.L, Zhang, H, Zhou, D, Basta, N, Raun, W.R, Payton, M.E, Zazulak, A
• Format: Journal Article
• Language: English
• Published: Madison Soil Science Society 01-01-2008; Soil Science Society of America; American Society of Agronomy
• Subjects: agricultural soils; Agronomy. Soil science and plant productions; Ammonium; Ammonium nitrate; application rate; Biological and medical sciences; Biosolids; chemical concentration; Earth sciences; Earth, ocean, space; environmental fate; Exact sciences and technology; fertilizer application; Fertilizers; Fundamental and applied biological sciences. Psychology; heavy metals; Loam soils; Manures; Metals; Moisture content; nitrogen; phosphorus; phosphorus satural index; Pollution load; R&D; Research & development; Saturation index; Sludge; soil nutrients; Soil pH; Soil properties; soil salinity; Soil science; Soils; Surficial geology; trace element fertilizers; Triticum aestivum; wastewater; wastewater treatment; Water quality; Winter wheat; Oklahoma; USA, Oklahoma; Soil science; Earth science
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj2007.0025

The USEPA Part 503 rule did not directly specify the amount of sludge-borne P that can be applied but allowed application rates based on the recommended N requirement of a crop. Monitoring of long-term application of biosolids is important to protect both soil and water quality. Biosolids and ammonium nitrate were annually applied for 13 yr to winter wheat at six plant available N (PAN) rates: 0, 45, 90, 180, 269, 536 kg N ha-1 yr-1. Biosolids application did not increase soil pH but increased levels of total C, total N, NH4-N, NO3-N, and electrical conductivity (EC). Soil concentrations of Cd, Cu, Pb, Mo, and Zn were greater in biosolid-treated plots but were <24% of their respective cumulative pollutant loading rates. Application of biosolids increased plant micronutrient B, Cu, Fe, and Zn concentrations. The addition of biosolids to the Norge soil (fine-silty, mixed, active, thermic Udic Paleustoll) increased Mehlich 3 plant available P (M3P) and water soluble P (WSP) and these P levels were well correlated with biosolids application rate. Application of biosolids at rates of >or= 2 times the recommended agronomic rate of 90 kg PAN ha-1 resulted in M3P concentrations that exceeded an environmental threshold of 200 mg kg-1 established by the USDA-NRCS for the land application of manures in Oklahoma non-nutrient limited watersheds. Significant relationships were found between the ammonium oxalate P saturation index (PSI(ox)) and M3P as well as between PSI(ox) and WSP. It appears the repeated long-term application of biosolids above the N agronomic rate should be avoided and application should be based on other criteria such as an agronomic P threshold, an environmental P threshold, or a P site index.