Assessment of irrigation use on crop yield and water supplies in the Midwestern U.S

Chen, Wei-Chih. Ph.D., Purdue University, December 2014. Assessment of Irrigation Use on Crop Yield and Water Supplies in the Midwestern U.S. Major Professor: Keith Cherkauer. Climate plays an important role in many aspects of hydrological and agricultural systems. Temperature and precipitation are usually the main forcing inputs for hydrological and agricultural simulations, while wind effect has generally been neglected in previous research. Wind speed is, however, an important factor for many physical processes, including evaporation from soil, and transpiration from plants. In order to investigate how climate variability impacts agricultural production, there are three hypotheses addressed in this dissertation. Hypothesis 1 is that the representation of changing wind speed will play an important role in the simulation of hydrological processes, and that the effect of wind speed will directly affect soil hydrology and evapotranspiration. Hypothesis 1 is tested using a factor separation analysis to quantify the contribution of projected future wind speed to hydrologic change under future climate. The result showed that changes in wind speed affected soil hydrology and evapotranspiration directly. Hypothesis 2 is that the application of irrigation will be significantly beneficial for crop productivity in the future as it will mitigate risk associated with water