Study Water Producton Function And Water-saving Irrigation System Of Winter Wheat In Jinghuiqu Irrigation District, Shanxi

Jinghuiqu irrigation area is an important grain growing area in Guanzhong Plain area of Shanxi Province.In recent years,due to the adjustment of planting structure and the degree of agricultural mechanization,the water system of irrigation area becomes unreasonable,which leads to the contradiction between water supply and demand,water resource utilization is low and so on.In the Jinghuqu irrigation area for 3 years of field winter wheat irrigation system test,the test set up 8 irrigation treatment,each treatment repeated 2 times.The effects of different irrigation treatments on the physiological shape,water requirement,yield and water use efficiency of winter wheat were studied.Based on the experimental data of three years,the water production function was selected,and the dynamic programming method The model of optimal irrigation system was established and solved.Get the following conclusions:(1)The effects of irrigation at different growth stages on the plant morphology of winter wheat were mainly on tiller number and plant height.The number of tillers in the change trend mainly showed two high peaks,respectively,in the early tillering stage(at sowing stage)and early turn period,so in these two stages to maintain water deficit,winter wheat development and yield have a favorable impact.The differences in plant height were mainly manifested in the period of turning green and jointing,and the situation of water deficit in these two fertility stages would result in a decrease in plant height.(2)Based on the data of field trials,studied the effect of irrigation at different growth stages on wheat yield and water use efficiency,in order to determine the appropriate irrigation system under different rainfall year.The results indicatedthat under the same irrigation ration,different irrigation periods had significant effect on yield,when the drought appeared in the early growth stage,winter irrigation is the basic guarantee of winter wheat yield.During jointing stage and heading stage,soil moisture has a great influence on the growth of winter wheat,which is the key period for the growth and development of winter wheat.In 2013-2014(75% years)the optimization irrigation schedule for winter wheat was three times of irrigation in Pre-sowing water,jointing stage and filling stage,irrigation quota is 315mm;In 2014-2015 and 2015-2016(50% water)the best appropriate irrigation system is was three times of irrigation in overwintering stage,jointing stage and heading&filling stage,irrigation quota is 341 mm.(3)Based on the data and meteorological data of winter wheat irrigation design experiment,Blank,Stewart,Minhas and Jensen models were selected to determine the corresponding sensitivity coefficient of each model,and the model was validated.Finally,the Jensen model was the most suitable Jinghuqu irrigation area Water production function model.(4)The optimal irrigation system model was established by using the dynamic programming method.Based on the relative output value as the objective function,the available irrigation water quantity,soil water content and evapotranspiration were used as the constraint conditions to optimize the modeling.For different precipitation assurance rates,the optimal irrigation system for winter wheat is given.