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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #333347
Title: Comparison of strong acid extraction methods for “total phosphorus” determination in soils: EPA 3050B and EPA 3051

Author
item Church, Clinton
item SPARGO, JOHN - Pennsylvania State University
item Fishel, Sarah - Sarah K Marshall

Submitted to: Agricultural & Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2017
Publication Date: 5/8/2017
Citation: Church, C., Spargo, J.T., Fishel, S.K. 2017. Comparison of strong acid extraction methods for “total phosphorus” determination in soils: EPA 3050B and EPA 3051. Agricultural and Environmental Letters.2:160037(2017).doi: 10.2134/ael2016.09.0037.

Interpretive Summary: The emphasis on controlling environmental phosphorus (P) losses from agriculture has expanded the role of agricultural laboratories in testing a variety of media for P, including soils, waste residuals, manures, and runoff waters. However, almost no rigorous comparisons of methods indicate what methods are best suited for this purpose. In a comparison of EPA3050B and EPA3051 (both with and sans hydrochloric acid (HCl) addition), on a variety of acidic and alkaline soils typical of the Northeastern USA, we found that both methods gave reliable and comparable results.

Technical Abstract: The emphasis on controlling environmental phosphorus (P) losses from agriculture has expanded the role of agricultural laboratories in testing a variety of media for P, including soils, waste residuals, manures, and runoff waters. To estimate total P in soils strong acid extraction methods, which actually measure “total recoverable P”, are generally employed as traditional digestion methods possess an array of operational concerns and safety limitations and typically extract forms of P that are of limited environmental import. We sought to assess the merits of two strong acid extraction methods, EPA3050B and EPA3051 (both with and sans hydrochloric acid (HCl) addition), on a variety of acidic and alkaline soils typical of the Northeastern USA. Both methods gave reliable results, though 3050B sans HCl showed somewhat lower (though not statistically significant) extraction efficiencies. EPA3051 was unaffected by the addition of HCl, and its extraction efficiencies were approximately 7% greater when compared to EPA3050B, though the differences were only significant in one of the seven soils tested.