Simulating Soybean Water Stress Effects with RZWQM and CROPGRO Models

and DSSAT could be used to predict success or failure of soybean in dryland crop rotations. But for a crop The Root Zone Water Quality Model (RZWQM) and CROPmodel to be a valuable aid in predicting the effects, and GRO-Soybean simulate soybean [Glycine max (L.) Merr.] growth, success or failure, of intensifying and diversifying rotadevelopment, and yield. The models require calibration for soybean grown in the specific environmental conditions of the central Great tions and using new crops, it must be able to adequately Plains before any long-term assessments can be made of dryland respond to varying degree and timing of water stress soybean yield potential under the highly variable precipitation pat(Tsuji et al., 1998). terns of this area. The objective of this study was to calibrate and test Several recent reports have described the perforRZWQM and CROPGRO-Soybean for soybean growth, yield, and mance of the generic crop production model (Hanson, water use under a range of water stress conditions normally encoun2000) used in the RZWQM (Landa et al., 1999; Wu et tered by dryland production systems in the central Great Plains. Data al., 1999; Jaynes and Miller, 1999; Martin and Watts, from five experiments, each with four levels of water availability (2