Study On Evaluation And Optimal Allocation Of Agricultural Water Resources In Sichuan Province

The sustainable utilization of water resources is the base and core of sustainable development agriculture. The continue using of agricultural water resources will profound influence the continue using of water resources, and affect the sustainable development of the whole society, none but adopt scientific and reasonable technique and its countermeasures, the regional agronomic can sustainable develop better. The sustainable utilization research of agricultural water resources on irrigation area are relatively perfect and systemic at present, but there are no uniform standard and methods about sustainable utilization research of macroscopical area agricultural water resources. Based on macroscopical point, for the mostly problems of the exploitation and utilization of agricultural water resources: the inefficient exploitation and utilization of agricultural water resource and the lack of big backbone move and store project, the short and severely waste of cultural water resources, the aging of irrigation engineering, the increasingly deteriorate of agro-water- environment; the obvious tendency of "agriculture change into non-agriculture" water resources; the division management of agricultural water resources and synthetical benefit lowness. So, to aim at these problems, and to carry out the sustainable development of agriculture Sichuan province, the investigation of agricultural water resources is very important, and it is one of the urgent questions of agricultural development in the dissertation.The index systems of the saving water agricultural benefit evaluation and of the sustainable utilization of agricultural water resource of Sichuan province by expert consultation and typical investigation are put forward, suitable evaluation method to evaluate the condition of agricultural water resource of Sichuan province are chose, for the problem of short of agricultural water resources, the need of agricultural water amount of 2010 and 2020 are forecasted using regressionanalysis and grey system model, and quota of water demand, the allocation of agricultural water resource using big system decomposition and coordination principle and water right system are discussed. Agricultural water resources collocation styles are brougt forward, the primary conclusion are as the follow:(1) Based on the investigation data of current land use in 2003, the of agricultural water resources amount of Sichuan province are calculated. The agricultural water resources amount of Sichuan province is 4005.36 ×10~8m~3, including the soil water resource is 1457.79×10~8m~3, account for 35.80% of the whole province agricultural water resources, there is significant difference among different agricultural land use. The agricultural water consumption, including the soil water resources is 1584.57×10~8m~3, the non-gravity water resources that is provided by soil take up 92.00%, Soil water is the provider of agricultural water, we should highly attach importance to the contribute of soil water resources to agriculture not only in the theory research of agricultural water, but also in the production and practice.(2) Based on the sustainable utilization of water resources, sustainable utilization index system of Sichuan agricultural resource which contains lsubject,4 categories including 17 indexes altogether are built up. From subject and categories, the sustainable utilization degree of Sichuan agricultural water resources are evaluated using analytic hierarchy process and fuzzy comprehensive judgment, The synthetical subordinate degree of sustainable utilization of Sichuan agricultural water resources is 0.3210 that is belong to the inferior level sustainable utilization. Mianyang city locates in the comparative upper sustainable utilization degree of agricultural water resources, the 4 cites including Deyang, Suining, Neijiang, and Ziyang locate in the comparative medium sustainable utilization degree of agricultural water resources, the 14 cites including Chengdu, Zigong, Luzhou, Guangyuan, Leshan, Nanchong, Yibin, Guangan, Dazhou, Ya'an, Bazhong, Meishan, Liangshan locate in the comparative lower sustainable utilization degree of agricultural water resources, the 2 cities including Ganzi and A'ba locate in the comparative lowest sustainable utilization degree of agricultural water resources.In order to compare to other area, according to the indexes of national water resources evaluation,6 indexes are put, which 4 grade standard value for evaluation indexes are build up, the degree of sustainable utilization of agricultural water of Sichuan province are evaluated using fuzzy mode identifying method by computing the grade characteristic value, and the conclusion are as follow: the grade characteristic value of Sichuan province is range 3-4, close to 3, means locates at the lower and lowest sustainable utilization level. In the whole province 10 city 2-3 grade, means locate at medium and low sustainable utilization level, and 11 city and town locate at the low andlowest sustainable utilization level, the result basic inosculate fuzzy comprehensive judgment, the mainly reason is due to the difference of index system.(3) Based water-saving agricultural point, the dissertation analyzes the current water-saving agricultural development and its prdblems, and builds up the index systems of water-saving agricultural benefit evaluation, including 1 subject, 4 categories, 8 indexes, and 24 factors. The water-saving agriculture benefits are evaluated using the principal component analysis and multivariate linear weighted functional method, which results show that most of them are similar. One of them is principal component analysis. It brings forward seven principal components by characteristic value of principal component and variance weighting and reflects 87.112% (>85%) information of original indexes satisfying principal component analysis. Scores of seven principal components and synthetical score are used as evaluate standard of water saving agriculture. Overall benefits of Sichuan province are not high, but they have great development potential. There are great differences of water saving agriculture benefits between every city. Chengdu, Deiyang and Meishan are belong to the cities of the highest benefit; consequently, Zigong, Panzhihua, Mianyang, Suining, Leshan and Ya-an have mean benefit; low benefit zones include Ziyang, Bazhong, Dazhou, Guangan, Yibin, Nanchong, Neijiang, Guangyuan, Luzhou and Liangshan; and the last are Ganzi as well as Aba. The other is multivariate linear weighted functional. Synthetical evaluative value of water-saving agriculture in Sichuan is 0.4226. Integrative evaluation of estimate from each cities and states is always low and below 0.6. The evaluation value of these cities which include Chengdu, Deyang, Suining, Guangan, Bazhong is larger than 0.5 and the evaluation value of Zigong, Panzhihua, Luzhou, Mianyang, Guangyuan, Neijiang, Leshan, Nanchong, Yibin, Dazhou, Ya'an, Meishan and Ziyang is beteewn 0.4 and 0.5. The value, which is between 0.3 and 0.4, is only Liangshan state and Ganzi and A'ba are below 0.3.(4) Based on the irrigation area, water utilization, watered index, hydraulic engineering and water logging of Sichuan province, the dissertation forecasts the status of agricultural water need in 2010 and 2020. (i) According to some factors such as crop irrigation norm, water efficiency of irrigation and main crop planted area, this dissertation forecasts the agricultural actual water need of Sichuan province and each cities using quota of water demand method. From 1999 to 2003 the whole province average agricultural actual water demand is 189.60* 108m3, which present the trend to increase with years and differences of the change trend between them are so big. By and large, the trends can be divided into three kinds: increased, decreased and ill defined, (ii) the dissertation forecasts agricultural water demand in 2010 and 2020 using regression analysis, GM (1, 1) Grey system model and quota of water demand method. The results of regression analysis is that agricultural water demands of Sichuan province are 184.23*l08m3 and 190.49*108m' respectively;The results of GM (1,1) Grey system model is that agricultural water demands of Sichuan province are 204.88xI08m3 and 224.63* 108m3 respectively; quota of water demand method uses different factor of assurance to forecast. When factor of assurance is 50 percent, the agricultural water demand of the whole province are 175.79* 108m3 and 173.14* 108m3 respectively. In the same way, when factor of assurance is 75%, results are 214.50 and 213.19 hundred million m3 respectively; when factor of assurance is 95%, results are respectively 227.71*108m3 and 225.05 *108m3. (iii) No matter what methods to predict, the factors which influence the agricultural water demand prediction must be considered and each method is used in definite range.(5) On the assumption that soil texture is medium loam and making it a condition that paddy rice is planted in the paddy field in medium-arid year, and meanwhile 30%of wheat and rape is planted in the paddy field and corn and sweet potato are planted on the condition of dry land planting, from which the author can obtain configuration project of the agricultural water resource amount of Sichuan by according as the macro-system composition decomposition principle and solving the dynamic programming model. The project is the water resources configuration amount for rice is 1048236* 104m3, for corn is 70827*104m3s, for wheat is 63387*104m3, for sweet potato is 1906* 104m3, for rape is 51900*104m3. Research shows that the water amount for rice in Sichuan Province is the largest which is 81.50% of all amounts for 5 kinds of crops to irrigation amount. Water requirement of other crops is all less and rely on utilizing the soil water resource mainly. The sensitiveness index ^ value for crop growth stage is an index for reflecting the output of influence degree to moisture loses. When irrigation water resources is limited, it should be satisfy the stage of maximum Xs value firstly. Because of lacking some datum about moisture sensitive index in Sichuan, it will affect the accuracy of result by use the datum of other province to calculate. Besides considering the application of model, we should consider policy factors and experience of production to allocate water resources in macroscopical area. So proposing that it use plural non-linear return or other methods to do the research on distributing water resources in macroscopical area.The theory and method of sustainable utilization of agricultural water resources are discussed, but there were some issues what shall be ulteriorly probed into: (i) the results can not be compared with other investigations which are carried out in domestic and overseas because of the discrepancy of the index system and evaluating methods for the sustainable utilization of agricultural water resources. (ii) the agriculture water demand can be forecasted with the founded models, but the discrepancy between the forecasting results and practical demanding water quantity is resulted in the lack of statistical information or unreliability of statistical information, (iii) the veracity and practicality of calculating results are declined because of the excessive qualification. Some...