Hydrologic Controls on Phosphorus Loss from Upland Agricultural Watersheds
- William J. Gburek * and
- Andrew N. Sharpley
Development of strategies for controlling P loss from upland agricultural watersheds requires an ability to identify specific source areas of P at field and farm scales, and to predict their resultant effects at the watershed scale. Key to identification of P source areas is defining the interaction between P availability over the landscape and its potential for movement to the watershed outlet by runoff and erosion. A current weakness in quantifying this interaction is determining specific zones of runoff and erosion within a watershed, that is, source areas for the P transport mechanisms. Research results from a series of studies within a small, upland agricultural watershed in east-central Pennsylvania show that the zones of runoff production, and consequently the areas ultimately controlling most P transport, are often a limited and identifiable portion of the landscape. Quantifying the hydrologic controls on P transport within and from a watershed in this way allows us to focus management options on small and definable portions of the total watershed that contribute most export.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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