Authors

Abstract

Water scarcity has been a critical constraint to economic development in semi-arid areas of China, so optimizing irrigation scheduling has become essential. This study obtained quantitative relationships between crop yield, crop water consumption, and irrigation quantity based on the Hydrus-2D and Stewart models. Different irrigation scheduling scenarios were evaluated to obtain the best irrigation scheduling based on the principle of simultaneous water conservation and crop productivity improvement with the evaluation indicators of crop yield, water use efficiency (WUE), irrigation water use efficiency (IWUE), and Critic-Topsis method. Taking drip irrigation under mulch as an example, the problem of optimizing the irrigation scheduling for different typical years was calculated. The optimization results showed that in the wet, normal, dry, and very dry years the annual irrigation quantity should be 49.68 mm, 49.68 mm, 85.38 mm, and 123.72 mm, when the WUE as well as IWUE, increases significantly, which had less impact on the crop yield and can save irrigation quantity by 30.00%, 30.00%, 35.00%, 27.00%. This study used Hydrus-2D to make a new attempt in irrigation scheduling optimization, giving full play to the model's high accuracy in soil water transport simulation and flexibility in boundary condition simulation. The optimization results can provide a reference for achieving accurate control of irrigation quantity during the crop growth period and reasonable irrigation scheduling formulation for regional crops.

Abstract in Chinese

在中国半干旱农灌区水资源短缺一直是制约经济发展的关键因素，因此对灌溉制度进行优化变的十分重要。本文基于Hydrus-2D和Stewart模型，得到作物产量-耗水量-灌溉量的定量关系，利用Critic-Topsis法，以水资源节约和作物生产力同步提高为原则，将作物产量、水分生产率、灌溉水利用效率作为评价指标对不同情景方案下的灌溉制度进行评价，优选得到最佳灌溉制度。以膜下滴灌为例，求解了不同水平年的灌溉制度优化问题，优化结果表明，在丰水年、平水年、枯水年、干旱年的年灌水量应为49.68mm，49.68mm，85.38mm，123.72mm，水分利用效率以及灌溉水利用效率增加显著，对作物产量的影响较小的情况下，节约灌溉用水30.00%，30.00%，35.00%，27.00%。本文利用Hydrus-2D在灌溉制度优化方面进行了新的尝试，充分发挥模型对土壤水运移模拟的高精度性及对边界条件模拟的灵活性，优化结果可为实现作物生育期内灌水量的精准控制，地区作物的合理的灌水方案制定提供参考。