Use of models to simulate the effects of agricultural practices on nitrate loss with drainage water

Abstract

Two computer simulation models were used to determine the effects of different nitrogen (N) management practices and crop production systems on the loss of nitrate-nitrogen (NO 3N) with drainage waters from agricultural watersheds. The results of this simulation study show that larger applications of N fertilizer resulted in larger NO 3N losses through subsurface drainage. When the N application rate was increased from 75 to 225 kg/ha (a 200% increase), NO 3N loss with drainage water increased by an average of about 300%. Multiple applications of N fertilizer could reduce NO 3N leaching losses from 10 to 35% in comparison with single N applications. Also, NO 3N leaching losses were considerably less under a corn-soybean rotation than under a continuous corn production.