Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2020 Apr 15;713:136585. doi: 10.1016/j.scitotenv.2020.136585. Epub 2020 Jan 11.
Water scarcity and ecological degradation as a result of the expansion of irrigated agriculture in arid regions have become global issues. A better understanding of the changes in crop water requirements (CWRs) is important for promoting sustainable development, particularly the water resource management of transboundary rivers. In this study, the latest and complete meteorological station and crop area data, the CropWat model, and the slope method were used to estimate the CWR in the Syr Darya Basin (SDB) of Central Asia from 2000 to 2018. The spatiotemporal variation of the water requirements for primary crops at the city scale was first assessed. The impacts of climate and cultivated land change on the CWR were quantified, and the associated impacts of the CWR on the water resources and environment were discussed. The results revealed that the mean unit area CWR of the SDB was 944.1 mm and the rate of increase was 7.6 mm/a from 2000 to 2018. The area of the primary crops expanded by 5851.6 km, and the total CWR increased at a mean rate of 2.0 × 10 m/a, with the majority of this change being concentrated between 2010 and 2018. By 2018, the total CWR reached 194.8 × 10 m. The lower reaches of the SDB were associated with a high CWR and a high rate of increase. Along with the reduction in basin water resources, the increased CWR has exacerbated the water stress in the SDB. Sensitivity analysis indicated that the dominant factors influencing the change in the CWR are cultivated land change (65.0%) and climate change (35.0%). Owing to a reasonable crop planting structure, the middle reaches maintained a relatively low CWR and rate of increase. Given the predicted changes in climate, optimizing crop planting structure and controlling the expansion of cultivated land in order to reduce the CWR can help to mitigate water scarcity.
由于干旱地区灌溉农业的扩张导致水资源短缺和生态退化已成为全球性问题。更好地了解作物需水量 (CWR) 的变化对于促进可持续发展至关重要，特别是对于跨界河流的水资源管理。本研究利用最新和完整的气象站和作物面积数据、CropWat 模型和斜率法，估算了中亚锡尔河流域（SDB） 2000 年至 2018 年的作物需水量。首先评估了城市尺度主要作物需水量的时空变化。量化了气候和耕地变化对 CWR 的影响，并讨论了 CWR 对水资源和环境的影响。结果表明，SDB 的平均单位面积 CWR 为 944.1mm，2000 年至 2018 年的增长率为 7.6mm/a。主要作物面积增加了 5851.6km，总 CWR 以平均 2.0×10^9m/a 的速度增长，其中大部分变化集中在 2010 年至 2018 年之间。到 2018 年，总 CWR 达到 194.8×10^9m。SDB 的下游地区与高 CWR 和高增长率有关。随着流域水资源的减少，增加的 CWR 加剧了 SDB 的水资源压力。敏感性分析表明，影响 CWR 变化的主要因素是耕地变化（65.0%）和气候变化（35.0%）。由于合理的作物种植结构，中游地区保持了相对较低的 CWR 和增长率。鉴于气候变化的预测变化，优化作物种植结构和控制耕地扩张以减少 CWR，可以有助于缓解水资源短缺。
