干旱区农业灌溉边际效应分析

Analysis of Marginal Effect of Agricultural Irrigation in Arid Areas

新疆远离海洋降水稀少蒸发强烈,是我国极为干旱的内陆灌区,形成了独特的"沙漠绿洲,灌溉农业"格局。近20年来,新疆的总灌溉面积和高效节水灌溉面积一直呈增长趋势,尤其是"十一五"高效节水面积发展迅速,而总引用水量稳定在400亿m3左右,水资源的总量控制得以显现。从新疆灌溉系统中的主要投入因素与引用总水量目标关系考虑,运用柯布-道格拉斯模型对灌溉系统的主要影响因素与研究目标进行了边际效应分析研究。结果表明,目前灌溉系统总体报酬递增临界度大于1,灌溉系统现状趋于好的方面发展,高效节水灌溉单位面积增量边际效应及其对水资源的降耗贡献远高于常规灌溉。因此,大力提升新疆灌溉系统中高效节水规模比重,是现代灌溉农业可持续发展的必然选择。

Xinjiang is away from the ocean,the precipitation is very sparse and the evaporation is very strong.It is an arid inland irrigation district and a unique pattern of desert oasis and irrigation agriculture has been formed.In the last 20 years,the total irrigation area and efficient irrigation area in Xinjiang have appeared growing trend.Especially in the eleventh five-year period,the efficient water-saving area is developing rapidly,while the total water consumption quantities is stabilized at around 400 million m3,the total quantity control of water resources is realized.From the aspects of the relationship between the target of total water quantity and the main input factors in irrigation system,the Cobb-Douglas model is used to study the marginal effect of the main factors and the study target of irrigation systems.The results show that the current irrigation system overall increasing critical degree is greater than 1,the status of irrigation system has a good development tendency,the unit area incremental marginal effect and its contribution to the conservation of water resources of efficient water-saving are much higher than that of the conventional irrigation.Therefore,significantly increasing the ratio of efficient irrigation systems is the inevitable selection for the sustainable development of modern irrigation agriculture.