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This article in JEQ

  1. Vol. 30 No. 3, p. 1023-1033
    Received: May 31, 2000

    * Corresponding author(s): rmaguire@udel.edu
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Relationships between Biosolids Treatment Process and Soil Phosphorus Availability

  1. R.O. Maguire *a,
  2. J.T. Simsa,
  3. S.K. Dentelb,
  4. F.J. Coalec and
  5. J.T. Mahb
  1. a Dep. Plant and Soil Science, Univ. of Delaware, Newark, DE 19717-1303
    b Dep. Civil and Environmental Engineering, Univ. of Delaware, Newark, DE 19717-1303
    c Dep. Natural Resource Science and Landscape Architecture, Univ. of Maryland, College Park, MD 20742-5821


Laws mandating phosphorus (P)-based nutrient management plans have been passed in several U.S. Mid-Atlantic states. Biosolids (sewage sludge) are frequently applied to agricultural land and in this study we evaluated how biosolids treatment processes and biosolids P tests were related to P behavior in biosolids-amended soils. Eight biosolids generated by different treatment processes, with respect to digestion and iron (Fe), aluminum (Al), and lime addition, and a poultry litter (PL), were incubated with an Elkton silt loam (fine-silty, mixed, active, mesic Typic Endoaquult) and a Suffolk sandy loam (fine-loamy, siliceous, semiactive, thermic Typic Hapludult) for 51 d. The amended soils were analyzed at 1 and 51 d for water-soluble phosphorus (WSP), iron-oxide strip–extractable phosphorus (FeO-P), Mehlich-1 P and pH. The biosolids and PL were analyzed for P, Fe, and Al by USEPA 3050 acid–peroxide digestion and acid ammonium oxalate, Mehlich-1, and Mehlich-3 extractions. Biosolids and PL amendments increased extractable P in the Suffolk sandy loam to a greater extent than in the Elkton silt loam throughout the 51 d of the incubation. The trend of extractable WSP, FeO-P, and Mehlich-1 P generally followed the pattern: [soils amended with biosolids produced without the use of Fe or Al] > [PL and biosolids produced using Fe or Al and lime] > [biosolids produced using only Fe and Al salts]. Mehlich-3 P and the molar ratio of P to [Al + Fe] by either the USEPA 3050 digestion or oxalate extraction of the biosolids were good predictors of changes in soil-extractable P following biosolids but not PL amendment. Therefore, the testing of biosolids for P availability, rather than total P, is a more appropriate tool for predicting extractable P from the biosolids-amended soils used in this study.

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Copyright © 2001. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.30:1023–1033.