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This article in JEQ

  1. Vol. 30 No. 5, p. 1790-1795
    Received: July 7, 2000

    * Corresponding author(s): mcabrera@arches.uga.edu


Phosphorus Losses from Grasslands Fertilized with Broiler Litter

  1. S. T. Piersona,
  2. M. L. Cabrera *b,
  3. G. K. Evanyloa,
  4. P. D. Schroederb,
  5. D. E. Radcliffeb,
  6. H. A. Kuykendalld,
  7. V. W. Bensone,
  8. J. R. Williamsf,
  9. C. S. Hovelandb and
  10. M. A. McCannc
  1. a Dep. of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg, VA 24061
    b Dep. of Crop and Soil Sciences, Univ. of Georgia, Athens, GA 30602
    d USDA Natural Resources Conservation Service, Athens, GA 30601
    e Dep. of Agric. Economics, Univ. of Missouri-Columbia, Columbia, MO 65201
    f Blackland Research Center, 808 East Blackland Rd., Temple, TX 76502
    c Animal and Dairy Science Dep., Univ. of Georgia, Athens, GA 30602


Broiler litter, a mixture of poultry excreta and bedding material, is commonly used to fertilize grasslands in the southeastern USA. Previous work has shown that under certain situations, application of broiler (Gallus gallus domesticus) litter to grasslands may lead to elevated levels of phosphorus (P) in surface runoff. The EPIC simulation model may be a useful tool to identify those situations. This work was conducted to evaluate EPIC's ability to simulate event and annual runoff volume and losses of dissolved reactive phosphorus (DRP) from tall fescue (Festuca arundinacea Schreb.)–bermudagrass [Cynodon dactylon (L.) Pers.] paddocks fertilized with broiler litter. The EPIC simulations of event runoff volume showed a trend toward underestimation, particularly for runoff events > 30 mm. On an annual basis, EPIC also tended to underestimate runoff, especially at runoff volumes > 100 mm. Both event and annual runoff estimations were strongly associated with observed values, indicating that model calibration could improve the simulation of surface runoff volume. The relationship between simulated and observed values of DRP loss was relatively poor on an event basis (r = 0.65), but was stronger (r = 0.75) on an annual basis. In general, EPIC tended to underestimate annual DRP losses. This underestimation was apparently caused by the lack of an explicit mechanism to model broiler litter on the soil surface. These results suggested that additional work on the EPIC P submodel would be warranted to improve its simulation of surface application of broiler litter to grasslands.

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Copyright © 2001. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.30:1790–1795.