Author
 |
Sharpley, Andrew |
|
Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 5/3/2005 Publication Date: 11/1/2006 Citation: Sharpley, A.N. 2006. Modeling Phosphorus Movement from Agriculture to Surface Waters. In: Radcliffe, D. E., Cabrera, M. S., editors. Modeling Phosphorus in the Environment. Boca Raton, FL: CRC Press. P. 3-19. Interpretive Summary: An interpretive summary is not required. Technical Abstract: Modeling phosphorus (P) loss from agricultural watersheds is key to quantifying the long-term water quality benefits of alternative best management practices. Scientists engaged in this endeavor struggle to represent processes controlling P transport at scales and time frames that are meaningful to farmers, resource managers, and policy makers. To help overcome these challenges, we review salient issues facing scientists that model P transport, providing a conceptual framework from which process-based P transport models may be evaluated. Recent advances in quantifying the release of soil P to overland and subsurface flow show that extraction coefficients relating soil and flow P are variable but can be represented as a function of land cover or erosion. Existing information on best management effects on P export can be linked to watershed models to better represent changes in P transport. The main needs of P transport models are inclusion of flexible coefficients relating soil and overland flow P, manure management and P loss, stream channel effects on edge-of-field P losses prior to water body input, and linkage of watershed and water-body response models. Even so, it is essential that the most appropriate model be carefully selected to meet a user's needs, in terms of level of predictive accuracy needed, input data available, and scale of simulation being considered. |