灌溉用水有效利用系数尺度效应分析

指出灌溉用水有效利用系数尺度效应的含义，分析了灌溉用水有效利用系数随空间尺度加大而减少的规律及其原因；根据全国2006年各省测算数据分析，表明随灌区规模的增大，灌溉用水有效利用系数整体逐渐降低，呈现出明显的规律性。其中，大型灌区的灌溉用水有效利用系数变异程度最小，而小型灌区的变异程度最大；由于近年国家加大大型灌区节水改造与续建配套的投入，大中型灌区灌溉用水有效利用系数之间的差异越来越小，表明大型灌区节水改造投入已取得显著成效；漳河灌区2008年不同尺度测算结果表明．同一灌区随着空间尺度的减小，即灌区规模的减小，输水距离缩短，灌溉用水有效利用系数提高，符合一般规律。

Scale effect of effective utilization coefficient of irrigated water

The meaning of scale effect of effective utilization coefficient of irrigated water is presented, and the law and reason of changes of effective utilization coefficient of irrigated water along with increase and decrease of spatial scale are examined. According to the observed data of each province in 2006, it shows that effective utilization coefficient of irrigated water has been gradually decreased along with the enlargement of irrigation district. Among which, the variation degree of effective utilization coefficient of irrigated water is small in large irrigation district but big in small irrigation district. Due to the increase of government＇s input to large irrigation district rehabilitation, the variation degree of effective utilization coefficient of irrigated water becomes smaller in large and medium irrigation districts. The estimation result of Zhanghe Irrigation District in 2008 demonstrates that effective utilization coefficient of irrigated water is high along with decrease of spatial scale of the same irrigation district, i.e. smaller the irrigation district scale and shorter the water transporting distance, which complies with the general rule.