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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #154318

Title: DETERMINATION OF PHOSPHORUS SOURCE COEFFICIENTS FOR ORGANIC PHOSPHORUS SOURCES: LABORATORY STUDIES

Author
item Leytem, April
item SIMS, J - UNIVERSITY OF DELAWARE
item COALE, F - UNIVERSITY OF MARYLAND

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2003
Publication Date: 1/1/2004
Citation: Leytem, A.B., Sims, J.T., Coale, F.J. 2004. Determination of phosphorus source coefficients for organic phosphorus sources: laboratory studies. Journal of Environmental Quality. 33:380-388.

Interpretive Summary: Phosphorus (P) losses in runoff from application of manures and biosolids to agricultural land can negatively impact surface water sources. Leytem and Sims report that there are significant differences in the solubility and availability of P from varying organic P sources. The difference in solubility of organic P sources suggests that they pose different risks for P losses in runoff when land applied, and therefore should be weighted differently in any risk assessment. The use of a Phosphorus Source Coefficient (PSC) may be beneficial when determining risk of P losses from land application of manures and other organic P sources and could be used in risk assessments such as a phosphorus site index. These PSCs may also be useful for determining P application rates when organic P sources are applied to P deficient soils for use as a fertilizer source.

Technical Abstract: Phosphorus (P) losses in runoff from application of manures and biosolids to agricultural land are implicated in the degradation of water quality in the Chesapeake and Delaware Inland Bays. We conducted an incubation study to determine the relative P solubility and bioavailabity, referred to as P source coefficients (PSCs), for organic P sources which are typically land applied in the Mid-Atlantic U.S. Nine organic and one inorganic (KH2PO4) P amendments were applied to an Evesboro loamy sand (mesic, coated Typic Quartzipsamments) at a rate of 60 mg P/kg and incubated for 8 wk with subsamples analyzed at 2 and 8 wk. There was an increase in Mehlich-3 (M3-P), water soluble P (WS-P), iron-oxide strip extractable P (FeO-P), and Mehlich-3 phosphorus saturation ratio (M3-PSR) with P additions, which varied by P source. The trend of relative extractable WSP, FeO-P and M3-P generally followed the pattern [inorganic P] > [liquid and deep pit manures] > [manures and biosolids treated with metal salts or composted]. We found significant differences in the availability of P from varying organic P sources. The use of PSC may be beneficial when determining risk of P losses from land application of manures and other organic P sources and could be used in risk assessments such as a P site index. These PSC may also be useful for determining P application rates when organic P sources are applied to P deficient soils for use as a fertilizer source.