Study On Rice Water Production Function And Optimization Of Irrigation Schedule Of Cha Ha Yang Irrigation Area

As the advancement of people and the rapid development of world economy, the requirement quantity of water has been increasing day after day. The problem of water resource has been the widely concerned topic in the world. In China, 70 percent of overall water consumption is for the agriculture. It has been used to irrigation, and irrigated water is 90 percent of the whole agricultural using water. Rice is one of food-supplied crops, and is also the irrigated crop that has the biggest water consumption. Rice of north belongs to arid and semi-arid area, and the contrast between water supply and water consumption is more and more serious. Moreover, rice cannot be grown in some irrigation areas as a result of water scarcity. Accordingly, water-saving irrigation for rice is also one of the most important problems in developing high -yield, high -quality and high-efficiency agriculture during 21 century. Water-saving irrigation and deficient irrigation for rice growing have been the most important measures to keep the agriculture of rice area sustainable development.The author took Cha Hayang Irrigation Area of Heilongjiang Province as the example where experiment research has been carried out. Water production function models and optimal irrigation schedule model under deficient irrigation have been studied. And the results are as follows,(1) Taking sufficent irrigation treatment to rice as the contrast,the daily varying rule of net photosynthetic rate in different birth stage was preliminarily analysed ,besides, the varying rule of net photosynthetic in the whole birth stage was also analysed.(2) Least Square Regression has been used to analyze to rice experiment data of Cha Hayang Irrigation Area. And sensitivity indexes of Jensen model, Blank model, Stewart model and Singh model were comparatively studied, besides, fitting effects of every model have been theoretically tested through compound correlation index. The study showed that Jensen model was the most suiTab. model for rice of Cha Hayang Irrigation Area. Stewart model is reasonable. Blank model and Singh model are contrast to the varying regularity of water requirement and ordinary irrigation experience, so they are not suiTab. for rice of Cha Hayang Irrigation Area.(3) Accumulated-function of sensitivity index of Jensen model has been established. So contradiction between theoretic calculation and practical application of sensitivity index has been settled. The paper supplied an effective method for the use of crop water production function in practice.(4) Accelerating Genetic Algorithm has been adopted to calculating sensitivity indexes of every model, and was compared with results calculating through Least Square Regression. The comparisons showed that precisions of yield forecast of them were general same, and the former had higher uniformity.(5) In order to provide scientific foundation for optimal use of water resource, the optimal irrigation schedule calculated by Accelerating Genetic Algorithm was obtained for Cha Hayang Irrigation Area. Besides, the target of the calculating process was to seek for the maximum of relative yield during the optimization. The result showed that the optimizing irrigation ration was 22.4 percent less than local water-saving irrigation ration. Then utilization efficiency of water has been enhanced.