Tuesday, November 14, 2006
200-4
Using RZWQM and Drainmod NII to Simulate Drainage Water Management in Iowa.
Kelly Thorp, Dan Jaynes, and Rob Malone. USDA-ARS-National Soil Tilth Lab., 2150 Pammel Dr., Ames, IA 50011-4420
Water table management practices such as controlled drainage have the potential to reduce the amount of nitrate-nitrogen leaving agricultural systems through tile drains in the midwestern United States. Increases in crop yield may also be possible with improved management of water in the agricultural system. In this study, two process-oriented water quality models, RZWQM and Drainmod NII, were used to simulate water table management practices for a tile-drained agricultural field near Story City, Iowa. Each model was calibrated and validated using ten years of drainage and yield information collected at the site. The calibrated models were then used to simulate the effect of controlled drainage practices on nitrogen dynamics and crop yield over a sequence of historical weather information. Comparisons between the two models, in terms of performance and applicability to this problem, were also made.
Handout (.pdf format, 141.0 kb)