The effect of PET calculations in DRAINMOD on drainage and crop yields predictions in a subhumid vertisol soil district

The field hydrology model-DRAINMOD has several options for evapotranspiration (ET) calculation. The choice of each calculation method may affect modeling results because ET is one of the most important hydrologic components in field hydrology. ET calculation method may also have significant impact on crop yield predictions. As variable ET estimation methods are available nowadays, this paper presents a study of different ET inputs on simulated crop yields and drainage volume based on weather and soil data from a subhumid climate zone in China. The study results show that the effect of ET estimate on drainage and crop yield prediction is affected by crop species and growing period; more accurate ET estimate is also critical in simulating the effect of controlled drainage on field hydrology and crop production. The results of this study indicate that the effort contributed to better ET estimate is very important in model applications.