干旱区生态环境知识资源中心

A severe water shortage in arid and semiarid regions in China has triggered regulations limiting the use of irrigation water in desert-oasis agricultural systems. To determine the actual water demand of agricultural systems and to develop standards for a rational use of water resources, maize evapotranspiration rates was simulated using meta-analysis of published data, determined land-use and soil properties in Zhangye oasis area and then estimated water consumption with MODIS for arid northwestern China for the 2014 growing season. Farmland in Zhangye oasis totaled 2189.88 km(2) and accounted for 25.41% of the total oasis area; crop-protecting forestland totaled 8.56 km(2) and accounted for 0.10% of the total oasis area, grassland and unutilized land accounted for 1.85%, 71.48% of the total oasis area, respectively. Soil moisture capacity at saturation ranged from 21.0 to 33.0% and at field capacity from 21.0 to 31.5%. Soil bulk density ranged from 1.36 to 1.58 g cm(-3). Using meta-analysis, the simulated maize evapotranspiration rate was 655.91 +/- 20.53 mm. During 2014 growing season, minimum, optimum and maximum water consumption used for agricultural yields and oasis stability was 1.14 x 10 9 m(3), 1.46 x 10 9 m(3) and 1.75 x 10 9 m(3), respectively. In future research, increased big picture and high frequency data will allow operational monitoring of water use and requirements and irrigation at a regional scale.