Abstract
 Geospatial Approach to Nitrate-Leaching Index for Virginia Track: Agriculture Author(s): Patricia Donovan, W. Daniels Excess nitrate-N leaching into ground and surface waters from agricultural regions has been an increasing concern throughout the U.S. Currently, the nitrate-leaching index in Virginia is assigned by county based on tables that were "quasi-interpolated" from N-leaching isolines derived from the soil hydrologic groups and precipitation data. The availability of high-resolution GIS data allows for analysis which include raster based precipitation and evapotranspiration data and SSURGO digital soils data, making differential within-county assessments possible. The existing method used in Virginia, the New York state model, and a unique N-leaching model which includes evapotranspiration were analyzed using ArcGIS. While the results of the three LI methods do not vary significantly for most counties in Eastern Virginia, counties in the Shenandoah Valley have an average of 35,000 acres which would have an N-leaching index in the high and very high ranges if the NY-based or evapotranspiration models were applied. Patricia Donovan Virginia Polytechnic Institute and State University Crop and Soil Environmental Sciences 250 Smyth Hall-0404 Blacksburg , VA 24060 US Phone: 540.231.9795 Fax: 540.231.7630 E-mail: padonova@vt.edu W. Daniels Virginia Polytechnic Institute and State University Crop and Soil Environmental Sciences 244 Smyth Hall-0404 Blacksburg , VA 24061 US Phone: 540-231-7175 Fax: 540-231-7630 E-mail: wdaniels@vt.edu |
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