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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #138234


item Sharpley, Andrew
item Kleinman, Peter

Submitted to: Internet Web Page
Publication Type: Other
Publication Acceptance Date: 12/20/2002
Publication Date: 12/20/2002
Citation: Sharpley, A.N., Kleinman, P.J. 2002. National phosphorus research project: Pennsylvania - rain fall simulator and plot-scale comparison. Internet Web Page.

Interpretive Summary:

Technical Abstract: The effects of soil phosphorus (P) and field management on the loss of P in overland flow from Pennsylvania farmland is being studied as part of the National P Research Project (NPRP) using field-based rainfall simulators. The objective of this phase of research was to compare overland flow patterns (e.g., time to initiation, volume, discharge rate, peak flow) and the concentrations of P (dissolved and total P), and sediment discharge using the Water Erosion Prediction Protocol (WEPP) and NPRP rainfall simulators. Both simulators use the same rainfall generation system, nozzles, and intensity (70 mm/hour), although the size of plots (2 m2) used in the NPRP simulator, is much smaller than used by the WEPP simulator (32.6 m2). As the WEPP simulator more closely represents field-scale processes -- due to its large size and history of extensive testing, than does the NPRP simulator -- comparison of the two simulators provides insight into the hydrologic and P transport processes of the smaller, more portable NPRP simulator. The relative effect of soil P and management on P loss was similar between simulators, Thus, the NPRP simulator can be used to quantify the relationship between overland flow and soil P, assuming that the WEPP simulator is the standard protocol, which provides baseline data. Clearly, the NPRP is more portable, accessible to a wider range of fields, easier to install and requires much less labor to operate (two people are required to operate the NPRP and seven the WEPP simulator).