阿克苏河灌区作物需水量对气候变化的敏感性分析

Sensitivity Analysis of Crop Water Requirement to Meteorological Factors in Aksu Irrigation Area

阿克苏河灌区是中纬度干旱区典型的绿洲灌溉系统,同时也是新疆第二大灌区,了解灌区作物需水量可为灌区种植结构调整、水资源优化配置提供科学依据。本研究基于联合国粮农组织(FAO)的Penman-Monteith蒸散发模型,结合作物系数法估算了阿克苏灌区作物需水量的时空变化及其对气候因子和作物种植结构的敏感性。结果表明,1960—2015年阿克苏灌区多年平均作物需水量为586 mm,且呈显著上升趋势,上升速率为38.43 mm/10 a。随着气候变化和作物种植结构的改变,1990—2015年间作物需水量急剧增加,增加速率高达99.37 mm/10 a。对于不同作物类型,果林的需水量最大,高达829.8 mm,其次是棉花、水稻和玉米,小麦需水量最低。阿克苏灌区的作物需水量对日最高气温和日照时数较为敏感,而对最低气温、风速和水汽压的敏感度较低。当日最高气温升高2℃时,作物需水量增加4%,当日照时数增加10%时,作物需水量将增加3.2%。另外,作物需水量对作物种植结构非常敏感,当果林的种植面积比例增加10%时,作物需水量增加了12.1%。

The Aksu irrigation area,a typical oasis irrigation system in the mid-latitude arid region,is the second-largest irrigation unit in Xinjiang. Understanding the variations of crop water requirement can provide a scientific basis for plantation structure adjustment and water resources management. Based on the Penman-Monteith Evapotranspiration Model recommended by the Food and Agriculture Organization of the United Nations（FAO）,this study estimated the temporal and spatial variations of crop water requirement and its sensitivity to meteorological factors and crop structure in the Aksu irrigation area. Results showed that the average crop water requirement of Aksu irrigation area was 586 mm,and it significantly increased during the period of 1960-2015 with an increase rate of 38.43 mm/10 a. A significant upward trend of crop water requirement during the period of 1990-2015 was detected as a combined effects of climate change and evolution of crop structure. Crop water requirement of fruit tree was the largest（up to 829.8 mm）,followed by cotton,rice and maize,and water requirement of wheat was the lowest. The crop water requirement was more sensitive to maximum daily temperature and sunshine hours,while less sensitive to minimum temperature,wind speed and water vapor pressure. The crop water requirement increased by 4% when the maximum temperature rose by 2°C,while it increased by 3.2% when the sunshine hours increased by 10%. The crop water requirement was also sensitive to crop structure. The crop water requirement increased by 12.1% when the proportion of fruit trees increased 10%.