Agricultural and Biosystems Engineering Publications

Document Type

Article

Publication Version

Published Version

Publication Date

2001

Journal or Book Title

Transactions of the ASAE

Volume

44

Issue

2

First Page

269

Last Page

276

Research Focus Area(s)

Land and Water Resources Engineering

DOI

10.13031/2013.4688

Abstract

Using a model as a management tool requires testing of the model against field–measured data prior to its application for solving natural resource problems. This study was conducted to test the Root Zone Water Quality Model (RZWQM98) using four years (1996 to 1999) of field–measured data to simulate the effects of different N–application rates on corn yields and nitrate–nitrogen (NO3 –N) losses via subsurface drain water. Three N–application rates (low, medium, and high), each replicated three times, were applied to corn in 1996 and 1998 under a randomized complete block design at a tile–drained corn–soybean rotation field near Story City, Iowa. No N–fertilizer was applied to soybean in 1997 and 1999. Model calibration and evaluation were based on field measurements of tile flows, NO3 –N losses in tile water, and corn–soybean yields. On average, the model simulated tile flow, NO3 –N losses in tile water, and yields by showing a percent difference of –8%, 15%, and –4%, respectively, between measured and simulated values. The simulated yield response function showed that corn grain yields reached a plateau level when the N–application rate exceeded 200 kg–N/ha in 1996 and 170 kg–N/ha in 1998. These results suggest that RZWQM has the potential to simulate the effects of N–application rates on corn yields and NO3 –N losses with tile water. However, the model overestimated NO3 –N losses in subsurface drainage water during the soybean growth period, which may require further refinements in the N–cycling algorithm in relation to N2 –fixation and N–uptake processes.

Comments

This article was published in Transactions of the ASAE. Vol. 44(2): 269–276, doi:10.13031/2013.4688.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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