Jianqiang He
College of Water Resources and Architectural Engineering, Northwest A&F University
The crop-water model (CWM), or crop-water production function, which represents the relationship between crop yield and seasonal amount of applied water, is often required to optimize the irrigation managements. The commonly used CWMs include the Blank model, Jensen model, Minhas model, and many others. In these models, this kind of relationship was usually expressed in terms of values of evapotranspiration (ET) at different growth stages. The influences of lack of water at some specific growth stages on the final yield were reflected with a sensitive index, usually notated as , where represents the i-th growth stage. However, the CWM is not unique but varies among climate, soil zones, and between years, varieties, and crops. At the same time, it always requires a large data set that obtained from deliberately designed field experiments to develop such kind of models for the crop production in a specific area. This disadvantage will inevitably impede the adoption of CWM in actual agricultural water management. The crop models provide an alternative approach for the CWM development instead of traditional field experiments. Through crop model, the ET values and can be derived from some fundamental inputs that are easy to be obtained or well recorded by local management agencies, such as weather data, soil type, crop variety, final yields, phenology dates, and management information. In this study, the possibility of application of DSSAT (Decision Support System for Agrotechnology Transfer) model to develop CWM (e.g. Jensen model) for crop production will be explored. The project will be conduced based on the actual winter wheat production in Jinghui Irrigation District, Shaanxi Province, P.R. China.
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