绿洲灌区小麦水分生产率在不同尺度上的变化

水分生产率是衡量农业生产水平和农业用水科学性与合理性的综合指标。文章根据民乐县洪水河灌区1995-2006年的气象、灌溉用水量、灌溉面积、作物产量资料，从田间、斗渠、干渠、灌区4个不同尺度分析了小麦灌溉水分生产率年份间的变化情况。结果表明：不同尺度上平均灌溉水分生产率不同，田间尺度为1.414 kg/m3，斗渠尺度为1.013 kg/m3，干渠尺度为1.089 kg/m3，灌区尺度为0.894 kg/m3，并且不同尺度上的灌溉水分生产率在年份间的差异也比较大。2001年洪水河灌区实施了节水灌溉工程，不同尺度上的平均灌溉水分生产率在2001-2006年较1995-2000年有所提高，田间、斗渠、干渠、灌区分别提高了7.9%、19.4%、16.5%、7.4%，说明目前斗渠、干渠尺度上节水力度大，节水效益明显，而灌区尺度还有较大的节水潜力，应成为未来农业节水研究的重点。

Change of water productivity of wheat at different scales in oasis irrigation districts

Water productivity is an integrated index that evaluated agriculture production level and scientific and rationality of agricultural water. According to the data of meteorological, irrigation water use, irrigation area and crop yields of Hongshuihe irrigation districts from 1995 to 2006 in Minle County, Gansu Province, the variations of irrigation water productivity of wheat at four different scales which consist of farm scale, lateral canal scale, main canal scale and irrigation district scale were analyzed. The results indicated that the average values of irrigation water productivity of wheat calculated for different scales and different years were difference, the datum at farm scale was 1.414 kg/m3, lateral canal scale was 1.013 kg/m3, main canal scale was 1.089 kg/m3 and irrigation districts scale was 0.894 kg/m3. Also, differences of irrigation water productivity were bigger in years for different scales. The water saving irrigation project was put in practice in Hongshuihe irrigation districts in 2001. The average of irrigation water productivity of wheat was promoted obviously from 2001 to 2006 than that from 1995 to 2000. And the average from 2001 to 2006 was raised by 7.9%, 19.4%, 16.5%, 7.4%, respectively for farm scale, lateral canal scale, main canal scale and irrigation district scale, which showed that water saving was obvious benefit at lateral canal scale and main canal scale. At the same time the results also showed that water saving was considerable potential at irrigation district scale. Therefore the emphases of research works for agriculture water saving will be in irrigation district scale in the future.