Li Man, Zhang Junjie, Tan Chunping, Liu Huancai, He Qiaofeng
College of Geographical Sciences, Shanxi Normal University, Taiyuan, 030031, China.
Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, 610200, China.
Sci Rep. 2024 Aug 1;14(1):17843. doi: 10.1038/s41598-024-68845-2.
Quantitatively predicting the impacts of climate change on water demands of various crops is essential for developing measures to ensure food security, sustainable agriculture, and water resources management, especially in arid regions. This study explored the water footprints (WFs) of nine major crops in the middle and downstream areas of Shule River Basin, Northwest China, from 1989 to 2020 using the WF theory and CROPWAT model and predicted the future WFs of these crops under four emission and socio-economic pathway (SSPs-RCPs) scenarios, which provides scientific support for actively responding to the negative impacts of climate change in arid regions. Results indicated: (1) an increasing trend of the overall crop WF, with blue WF accounting for 80.31-99.33% of the total WF in the last 30 years. Owing to differences of planting structure, water-conservation technologies, and other factors, the multi-year average WF per unit area of crops was 0.75 × 10 m hm in downstream area, which was higher than that in midstream area (0.57 × 10 m hm) in the last 30 years; therefore agricultural water use efficiency in the downstream area was lower than that in the midstream area, implying that the midstream area has more efficient agricultural water utilization. (2) an initial increase and then decrease of crop WFs in the study area under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios by the end of the century, reaching their peak in 2030s which was higher than that from 1989 to 2020; with the maximum growth rates in the midstream area ranging from -0.85% in SSP5-8.5 to 5.33% in SSP2-4.5 and 29.74% in SSP5-8.5 to 34.71% in SSP2-4.5 in the downstream area. The local agricultural water demand would continue to increase and water scarcity issues would be more severe in the next 10-20 years, affecting downstream areas more. Under the SSP3-7.0 scenario, crop WF values of the midstream and downstream regions will be 2.63 × 10 m and 4.22 × 10 m in 2030, respectively, which is significantly higher than those of other scenarios and show a long-term growth trend. The growth rate of the midstream and downstream regions will reach 44.71% and 81.12%, respectively, by the end of this century, so the local agricultural water use would be facing more strain if this scenario materializes in the future. Therefore, the Shule River Basin should encourage development of water-saving irrigation technologies, adjust the planting ratio of high water consuming crops, and identify other measures to improve water resource utilization efficiency to cope with future water resource pressures.
定量预测气候变化对各种作物需水量的影响，对于制定确保粮食安全、可持续农业和水资源管理的措施至关重要，特别是在干旱地区。本研究利用水足迹理论和CROPWAT模型，探讨了1989年至2020年中国西北疏勒河流域中下游地区9种主要作物的水足迹，并预测了在四种排放和社会经济路径（SSPs-RCPs）情景下这些作物未来的水足迹，为积极应对干旱地区气候变化的负面影响提供科学支持。结果表明：（1）作物总水足迹呈增加趋势，过去30年蓝色水足迹占总水足迹的80.31%-99.33%。由于种植结构、节水技术等因素的差异，过去30年下游地区作物单位面积多年平均水足迹为0.75×10⁴m³/hm²，高于中游地区（0.57×10⁴m³/hm²）；因此下游地区农业用水效率低于中游地区，这意味着中游地区农业用水利用效率更高。（2）在SSP1-2.6、SSP2-4.5和SSP5-8.5情景下，到本世纪末，研究区域内作物水足迹先增加后减少，在2030年代达到峰值，高于1989年至2020年的水平；中游地区最大增长率在SSP5-8.5情景下为-0.85%，在SSP2-4.5情景下为5.33%，下游地区在SSP5-8.5情景下为29.74%，在SSP2-4.5情景下为34.71%。未来10-20年，当地农业用水需求将持续增加，缺水问题将更加严重，对下游地区影响更大。在SSP3-7.0情景下，2030年中游和下游地区作物水足迹值分别为2.63×10⁴m³和4.22×10⁴m³，显著高于其他情景，并呈长期增长趋势。到本世纪末，中游和下游地区增长率将分别达到44.71%和81.12%，因此如果未来这种情景成为现实，当地农业用水将面临更大压力。因此，疏勒河流域应鼓励发展节水灌溉技术，调整高耗水作物种植比例，并确定其他提高水资源利用效率的措施，以应对未来的水资源压力。
