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Phosphorus Losses from Grasslands Fertilized with Broiler Litter: EPIC Simulations
Author(s) -
Pierson S. T.,
Cabrera M. L.,
Evanylo G. K.,
Schroeder P. D.,
Radcliffe D. E.,
Kuykendall H. A.,
Benson V. W.,
Williams J. R.,
Hoveland C. S.,
McCann M. A.
Publication year - 2001
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2001.3051790x
Subject(s) - surface runoff , environmental science , litter , cynodon dactylon , festuca arundinacea , broiler , zoology , hydrology (agriculture) , phosphorus , agronomy , ecology , biology , chemistry , poaceae , geotechnical engineering , organic chemistry , engineering
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.