Insufficient Irrigation System Simulation And Regional Strategy Under Interplanting Mode Based On Cropwat Model In Hetao Irrigation Area

Under the background of the insufficient irrigation test under interplanting condition in Hetao Irrigation Area of Inner Mongolia, presented the insufficient irrigation test of and study on the interplanting of wheat and corns in Hetao Irrigation Area by adopting CROPWAT model as the study tool, and preliminary discussion on favorable irrigation system for interplanting of wheat and corns was carried out. The regional irrigation system was simulated and optimized. Based on systematic statistical analysis of the test, the following conclusions were drawn:(1) Based on the impact of insufficient irrigation on crop, the impact of soil moisture stress in different growth periods of interplanting crops on the crop yield and physiological conditions were analyzed. The changes of indexes (such as plant height and leaf area) intuitively reflected the degree of moisture stress suffered in different periods during the growth of the crops. As to the crop coefficient, the weighted average values of the two crops were adopted. The crops are in great demand for water and light in the medium period of their growth, and the crop coefficient changes between the coefficients of the two crops.(2) The crops have high evapotranspiration in their growth period provided that the planting structure is rational (1:1), and the water consumption caused by actual evapotranspiration reached4.3mm/d in this period. As to the correlation between the evapotranspiration and yield, evapotranspiration and yield maintain synchronous changes. According to the crop water production function in the whole growth period and irrigation period of interplanting crops, the key factor that affected the wheat yield is water deficit from booting to later period of grain-filling, while the key factor that affected the corns yield is water deficit in the early period of grain-filling.(3) The applicability of the CROPWAT model was demonstrated, and on this basis,13kinds of water changes in insufficient irrigation are simulated by applying the CROPWAT model. The result shows that different water changes occurred due to irrigation water adjustment in different periods. In some cases, the irrigation quota was not rationally allocated, while in some other cases, irrigation water loss occurred. The irrational allocation of irrigation quota will make the crops in critical growth period suffer from water stress due to shortage of irrigation water, which is bound to affect the yield in the future.(4) The result of irrigation system optimization based on Cropwat model shows that the irrigation quantity for the interplanted wheat and corns in growth period are392mm (six types of water are optimal) and426mm (four types of water are optimal). The interplanted crops receiving the aforementioned quantity of irrigation can make effective use of such irrigation, and water stress in critical period can be avoided.(5) We also stimulated and optimized the regional optimal water-saving irrigation system by applying the CROPWAT model. Such optimization was performed on the basis of existing study on the insufficient irrigation system, and provided effective reference for the optimization of the planting pattern (with existing fixed planting proportion) of wheat, interplanting of wheat and corns as well as corns.