chapter  16
20 Pages

Small Watershed Data Collection to Support Phosphorus Modeling

Research and development of improved phosphorus (P) modeling methods is often hampered by the lack of adequate data on P transported in runoff from various soil and land use conditions. These data are needed to enhance model representation of soil P cycling, off-site transport, and linkages to downstream impacts. Such enhancements

are necessary because models are increasingly used to guide legal, regulatory, and programmatic decisions, which directly affect farm income, water-supply protection, and ecological sustainability. Because of these implications, modelers must incorporate state-of-the-art science to accurately represent P mechanisms and to provide corresponding uncertainty estimates, both of which require appropriate P transport data for model calibration and evaluation (Sharpley et al. 2002).