Impact Of Drought On Summer Maize Yield In Gucheng(Heibei Province):a Case Of Model Study

Drought has become the main factor limiting maize production in the world. Research on the impact of drought on maize yield, is of great significance to ensure national food security. Study on drought of maize always makes through field water control experiment. It is difficult to control the moisture precisely, and the representativeness of sample is poor. Crop model from the perspective of system science, can dynamically simulate the physiological and ecological process of crop. And it has become one of the essential tools in the field of agricultural meteorological. Therefore, using crop model, simulation research on maize drought can compensate for the shortage of field water control experiment. It can detailedly simulate the quantitative changes of maize yield under different levels of water stress. The purpose of this study was to explore the method of experimental research on maize drought by using crop model.In this paper, the parameters of WOFOST crop model have been adjusted and revised under water stress. On this basis, drought effect to maize is studied based on same water stress period and similar drought degree during emergence to jointing and jointing to tasseling, and also studied the effect based on same water stress period and different drought degree, or similar drought degree and different drought period in same growing stage. The main outcomes in this study are as follows:(1) Field water control experiment data of summer maize Zhengdan958in Xiajin (Shandong Province) and Gucheng (Hebei Province) were used to calibrate the parameters of WOFOST crop model. The parameters were calibrated by calculating, such as thermal time, specific leaf area, fraction of above ground dry matter increase partitioned to leaves, stems and storage organs. And the parameters, such as maximum leaf CO2assimilation rate, the conversion efficiency of assimilates into roots, stems, leaves and storage organs, were adjusted by computer simulation. The results of simulation showed that the calibrated model can simulate growth and yield formation of summer maize Zhengdan958.(2) Field water control experiment data in limited soil moisture condition in Gucheng were used to revise the thermal time, specific leaf area, and the fraction of above ground dry matter increase partitioned to different organs. Adjust the parameters in WOFOST with above method, results showed that the calibrated model can simulate the growth and yield formation of summer maize Zhengdan958under drought condition in Gucheng of Heibei Province.(3) Drought effect to maize was studied based on the adjusted crop model. Results showed that in different growing stage, same water stress period and similar drought condition, product reduction caused by drought during emergence to jointing is smaller than the period of jointing to tasseling. In the same water limited period, severe drought caused much more yield reduction, and under similar drought condition, long time water stress leaded to a larger reduction. The WOFOST model revised by related parameters can basically simulate the impact of drought on maize yield.Using crop model, the impact of drought on maize yield was studied and some good results were approached. However, because of lack of data, some problems are needed to study further. The parameters of WOFOST model need been adjusted more precisely. And also we can do some simulation research on drought in different degree at any period of time.