Integrating Phosphorus Source and Soil Properties into Risk Assessments for Phosphorus Loss

• Published in: Soil Science Society of America journal Vol. 71; no. 2; pp. 551 - 560
• Main Authors: Shober, A.L, Sims, J.T
• Format: Journal Article
• Language: English
• Published: Madison Soil Science Society 01-03-2007; Soil Science Society of America; American Society of Agronomy
• Subjects: agricultural runoff; agricultural soils; Agricultural wastes; Agronomy. Soil science and plant productions; Analysis methods; animal manures; Applied sciences; Biological and medical sciences; Biosolids; Chemical treatment; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; equations; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Litter; losses from soil; Manures; Natural water pollution; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; Phosphorus; phosphorus saturation; phosphorus source coefficients; Pollution; Pollution, environment geology; regression analysis; Risk assessment; Soil and water pollution; Soil properties; Soil science; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; solubility; Water treatment and pollution; weighting factors; Mid-Atlantic region; United States; North America; America; Macronutrient(mineral); Coefficient; Integration; Poultry manure; Substance loss; Animal slurry; Property of soil; Phosphorus; North Eastern States (USA); Agricultural soil; Organic fertilizer; Risk analysis; Inorganic element; Source; Environmental engineering; Pollutant; Geographical division; Soil science; Northeast
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj2006.0253

Differences in P solubility of biosolids and manures, as a result of chemical treatment or other factors, have prompted states to incorporate weighting factors, sometimes called phosphorus source coefficients (PSCs), into P risk assessment tools. The value of PSCs in risk assessment has been demonstrated when organic P sources are surface-applied, but not when P sources are incorporated into soils. Ten organic P sources were incorporated into eight Mid-Atlantic soils (0-5 cm) at 135 kg total P ha-1 and incubated for 2, 30, and 180 d. Samples were analyzed for Mehlich 3 phosphorus (M3-P), M3-P saturation ratio (M3-PSR), and water-soluble phosphorus (WSP). Average increases in M3-P (26 mg kg-1) and M3-PSR (0.03) for all soils were similar for untreated manures and inorganic P compared to alum-treated poultry litter (APL) and biosolids (24 mg kg-1, 0.03). In contrast, average concentrations of soil WSP (2 d) were highest following incorporation of untreated manures and inorganic P (5.2-8.0 mg kg-1), followed by biosolids or APL (2.9-3.4 mg kg-1) and unamended soils (2.7 mg kg-1) with similar trends at 30 and 180 d. Source effects were most pronounced for soils with higher M3-PSR. Regression equations using soil M3-PSR and default PSCs could predict soil WSP at 2, 30, and 180 d (r2 = 0.67, 0.69, 0.60, all significant at P = 0.001). Based on our results, we developed a new weighting factor (using M3-PSR and default PSCs) for risk assessment tools that will better predict the potential for P loss when biosolids or manures are incorporated into Mid-Atlantic soils.