井渠双灌模式下黄河下游灌区水资源优化配置

Optimizing use of surface and groundwater for irrigation in lower reaches of the Yellow River Basin

【目的】探究井渠双灌模式下黄河下游灌区水平衡特征,分析渠水和地下水补灌的利用量和利用时机对作物水分消耗和产量的影响,为黄河下游灌区多水源综合利用和优化配置提供科学依据。【方法】基于散耗型水文模型对井渠双灌模式下的黄河下游灌区水平衡特征进行模拟,结合作物水分生产函数Jensen模型分析不同水源优化配置下冬小麦和夏玉米产量变化。【结果】在现状井渠双灌模式下,4月上旬、5月中下旬、6月上旬、7月下旬和8月上旬存在显著的水分亏缺,现状模式下10月中旬抽取地下水补灌的利用效果不佳,现有灌溉模式与纯渠水灌溉模式对作物产量的影响差别不大。冬小麦拔节期的相对产量对地下水补灌的响应最为敏感,夏玉米在抽穗期的相对产量对地下水补灌的响应最为敏感。对于冬小麦,在拔节期抽取70 mm地下水进行1次补灌即可实现显著增产,地表水与地下水适宜的利用比例为5.25∶1;对于夏玉米,在抽穗期抽取70mm地下水进行1次补灌即可实现显著增产,地表水和地下水适宜的利用比例约为4.4∶1。【结论】黄河下游灌区适宜的地下水补灌时机和利用量会对作物产量产生影响,建议在冬小麦拔节期抽取70 mm地下水进行1次补灌,在夏玉米抽穗期抽取70 mm地下水进行1次补灌,最适宜提升作物产量。

【Background】Combined use of surface water and groundwater for irrigation is a common practice in the lower reaches of the Yellow River Basin to control groundwater table at a desirable depth.In this paper,we investigate the optimal timing and quantity of irrigation using groundwater,based on crop water consumption and crop yields in the region.【Method】The analysis was based on modelling.A dissipative hydrological model was used to simulate water balance influenced by irrigation using different combinations of surface water and groundwater.The results were combined with the Jensen crop water production function to analyze the variation in the yields of winter wheat and summer corn with irrigation.【Result】①Significant water deficits were identified in early April,mid-to late-May,early June,late July,and early August,which negatively impacted crop yields.Supplementary irrigation using groundwater in mid-October did not have a noticeable effect on crop yield,and the difference in crop yields between irrigations using surface and groundwater and irrigation using only surface water was minimal.②The relative yield of winter wheat during the jointing stage and the relative yield of summer maize were sensitive to supplementary irrigation using groundwater,underscoring the importance of timing in irrigation using groundwater.③Supplementary irrigation of 40 mm using groundwater during the jointing stage of winter wheat notably increased its grain yield,with the optimal ratio of surface water to groundwater for irrigation being 5.25∶1.Irrigating 60 mm with groundwater for summer maize during the heading stage also boosted yield,with the optimal ratio of surface water to groundwater for irrigation being 4.4∶1.【Conclusion】Optimizing the timing and quantity of groundwater for irrigation is critical for improving crop yields in the lower reaches of the Yellow River basin.In our experimental study,irrigating 40 mm of groundwater for winter wheat during the jointing stage and 60 mm for summer maize during the heading stage can significantly improve their yields.