About Us | Help Videos | Contact Us | Subscriptions



This article in JEQ

  1. Vol. 29 No. 2, p. 508-514
    Received: Mar 29, 1999

    * Corresponding author(s): dou@cahp2.nbc.upenn.edu
Request Permissions


Laboratory Procedures for Characterizing Manure Phosphorus

  1. Z. Dou *,
  2. J. D. Toth,
  3. D. T. Galligan,
  4. C. F. Ramberg Jr. and
  5. J. D. Ferguson
  1. Center for Animal Health and Productivity, School of Veterinary Medicine, University of Pennsylvania. New Bolton Center, Kennett Square, PA 19348.



Phosphorus runoff from agricultural land contributes to accelerated eutrophication of surface waters. In areas with intensive animal farming, P loss from manured fields may be elevated due to high concentrations of soluble P in manure. We characterized P in dairy and poultry manure for the relative dissolution and fraction distribution using deionized water (H2O), 0.5 M NaHCO3, 0.1 M NaOH, 1.0 M HCl, and 5% trichloroacetic acid (TCA). Two extraction procedures were tested: (i) independent, with dried, ground samples being extracted repeatedly and P measured for each extractant; and (ii) sequential, with each sample being repeatedly extracted by H2O, NaHCO3, NaOH, and HCl, in that order. For the independent procedure, H2O extracted 53 to 64%, NaHCO3 64 to 72%, NaOH 33 to 54%, HCl 90 to 97%, and TCA 84 to 96% of the total P in manure. Sequentially, H2O, NaHCO3, NaOH, and HCl extracted 70, 14, 6, and 5% of the total P in the dairy, and 49, 19, 5, and 25% of the total P in the poultry sample, respectively. Manure P release was not greatly affected by shaking time but decreased rapidly with increasing number of repeated extractions. A large portion of P in manure being extractable by H2O or NaHCO3 suggests weak binding energy of P and hence a high susceptibility for loss to waters when conditions favor runoff. A 1-h shaking of manure with H2O may provide a quick measure of the relative magnitude of P that is most susceptible. Further investigation relating manure P fractions with P in runoff would help identify management alternatives for reduced P losses.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .