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摘要
A new simulation model for N dynamics, DRAINMOD-N II, has been previously evaluated for only a few sites. We evaluated the model using ten years (1996-2005) of measured data from a subsurface-drained, corn-soybean agricultural system near Story City, Iowa. Nitrogen fertilizer was applied to plots at low, medium, and high rates (5 7 to 67 kg N ha(-1). 114 to 135 kg N ha(-1). and 172 to 202 kg N ha(-1), respectively) during corn years, and nitrate (NO(3)) losses from subsurface drains under each plot were monitored biweekly for ten years. Average annual simulated and measured NO(3) losses in drainage water were 21.9 and 20.1 kg N ha(-1) for the low N rate, 26.6 and 26.5 kg N ha(-1) for the medium N rate, and 36.6 and 37. 0 kg N ha(-1) for the high N rate, respectively. The model efficiency statistics for DRAINMOD-N II simulations of annual subsurface drain NO(3) losses were 0.89, 0.95, and 0.94 for the low, medium, and high N rates, respectively. For the same experimental dataset, a comparison of DRAINMOD-N II simulations to that of another model that simulates hydrologic and N dynamics of agricultural systems, the RZWQM-DSSAT hybrid model, demonstrated that the two models were most different in their simulations of soybean N fixation, plant N uptake, and net N mineralization. Future field investigations should focus on generating better understandings of these processes. The results suggest that DPAINMOD-N II can reasonably simulate the effects of different corn-year N rates on losses of NO(3) through subsurface drainage lines and that simulations of subsurface drainage NO(3) losses by DRAINMOD-N II are comparable to that of RZWQM-DSSAT.
- 出版日期2009-10
