Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China; National Field Scientific Observation and Research Station on Efficient Water Use of Oasis Agriculture in Wuwei of Gansu Province, Wuwei 733009, China.
Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China; National Field Scientific Observation and Research Station on Efficient Water Use of Oasis Agriculture in Wuwei of Gansu Province, Wuwei 733009, China.
Sci Total Environ. 2022 Dec 20;853:158449. doi: 10.1016/j.scitotenv.2022.158449. Epub 2022 Sep 2.
Closing the irrigation water productivity (IWP) gap is an effective approach to alleviating water deficits and ensuring food security. However, few studies have attempted to quantify the IWP gap and the potential benefits of closing it. This study adopted the Heihe River Basin, the second-largest inland basin in China, as a typical study area. The aims of this study were to: (1) assess the positive achievements and potential risks triggered by the Heihe Ecological Water Diversion Project (EWDP) according to multi-source and multi-scale measured data; (2) analyze potential approaches to improve the IWP and quantify the potential benefits that can be achieved by closing its IWP gap. The results of this study indicated that the EWDP effectively reallocated surface water resources, replenished groundwater in the lower reaches, and facilitated the recovery of oases and economic development in the downstream regions. However, this project has indirectly led to an imbalance in the groundwater resource between the middle and lower reaches, resulting in decline in groundwater levels and degradation of local vegetation in the midstream regions. In addition, the expansion of cultivated land in the midstream and downstream oases has resulted in the deterioration of farmland environment. The water transfer resulted in a deceleration in the growth of IWP from 2.44 % to 1.15 %, and the existing IWP gap was 1.43 kg/m between 1984 and 2017. This study predicted a future increase in the IWP to 2.01 kg/m with a reduction in the gap to 0.45 kg/m while maintaining food production. The potential for conserving water in the Heihe agricultural region can reach 552 million m by reducing the planting area by 10 %, improving irrigation water use efficiency by 20 %, maintaining existing agricultural film inputs, and reducing fertilizer application by 10 %. Following the research recommendations can greatly alleviate the agricultural water shortage and over-extraction of groundwater in the middle reaches and ensure meeting ecological water demand in the lower reaches. This study can act as a reference for sustainable management of an endorheic basin.
提高灌溉水生产力（IWP）是缓解水资源短缺、保障粮食安全的有效途径。然而，鲜有研究尝试量化 IWP 缺口及其闭合带来的潜在效益。本研究以中国第二大内流河流域——黑河流域为典型区，目的是：（1）基于多源多尺度实测数据，评估黑河流域生态调水工程（EWDP）的积极成效与潜在风险；（2）分析提高 IWP 的潜力并量化闭合 IWP 缺口带来的潜在效益。研究结果表明，EWDP 有效调配了流域地表水资源，补给了下游地下水，促进了下游绿洲生态恢复和经济发展。然而，该工程间接导致中下游地下水资源失衡，引发中游地下水位下降和局部植被退化，以及中游和下游绿洲耕地扩张导致农田生态环境恶化。调水导致流域 IWP 增长率从 1984 年的 2.44%下降到 2017 年的 1.15%，1984—2017 年 IWP 缺口为 1.43kg/m3。研究预测，在维持粮食生产的前提下，未来流域 IWP 将增加到 2.01kg/m3，IWP 缺口减少到 0.45kg/m3。通过减少 10%耕地面积、提高 20%灌溉水利用效率、保持现有农膜投入和减少 10%化肥用量，流域农业节水潜力可达 5.52 亿 m3。这些措施可缓解流域中游农业用水短缺和地下水超采，保障下游生态需水。本研究可为内陆流域可持续管理提供参考。
