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This article in JEQ

  1. Vol. 28 No. 6, p. 1916-1928
    Received: Jan 25, 1999

    * Corresponding author(s): Junjie.Wu@orst.edu
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Metamodeling Potential Nitrate Water Pollution in the Central United States

  1. JunJie Wu * and
  2. Bruce A. Babcock
  1. Dep. of Agricultural and Resource Economics, 200A Ballard Extension Hall, Oregon State Univ., Corvallis, OR 97331;
    Center for Agric. and Rural Dev., 578 Heady Hall, Iowa State Univ., Ames, IA 50011-1070.



This article presents a modeling system for identifying the spatial patterns of potential water pollution from N fertilizer use in the central USA. The model uses a geographic information system (GIS) and a statistical technique to integrate an environmental process simulation model with spatially referenced databases on crop management and resource characteristics. The potential for NO3-N runoff and leaching was estimated for a total of 128 591 sites using information on soil, climate, crop, rotation, tillage, irrigation, and conservation practices at each site. For the entire study region, the average annual NO3-N runoff and leaching, respectively, were estimated to be 5 and 3 kg ha−1, which accounted for about 7 and 4% of total N applied. The potential for NO3-N runoff was relatively high in much of the Corn Belt, Kansas, and the Nebraska Platte River Basin, and the potential for NO3-N leaching was relatively high in Ohio, Indiana, and southern Illinois and Missouri. Because much of the area with high leaching potential was tile drained, a large portion of the leached NO3-N will be discharged to surface water, rather than continue downward to ground water. Finally, the model was applied to estimate the effects of a 25% reduction in N application rates and adoption of crop rotations on potential NO3-N runoff and leaching.

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