Great Plains Studies, Center for


Date of this Version

August 1993


Published in Great Plains Research 3:1 (August 1993). Copyright © 1993 The Center for Great Plains Studies, University of Nebraska–Lincoln. Used by permission.


The Seymour aquifer of north-central Texas is identified as containing elevated levels of nitrate. The area has been designated as a Hydrologic Unit Area under the President's Water Quality Initiative. The effect of alternative production practices on the relative changes in nitrate leaching through the vadose zone was measured by adding an extended soil profile in the EPIC-WQ simulation model. Net returns from alternative production methods were estimated by using returns from associated yield and adjusting the cost of different levels of nitrogen, irrigation, and harvesting. Trade offs between nitrate percolation and net returns were explored by plotting the net returns percolation data points for various methods of production. The results indicate that the relationship between nitrate percolation and net returns is not strictly positive for all production methods; potential remains where a lower percolation level could be achieved without a significant reduction in farmer's profit.