基于水分供需关系的冬小麦夏玉米节水灌溉模式研究

Water-saving irrigation modes based on water supply and demand of winter wheat and summer maize

  • 摘要: 节水灌溉是解决水资源短缺问题的重要途径之一。在长期田间试验的基础上, 运用Hydrus-1D模型对研究区冬小麦 夏玉米轮作条件下的田间水分运移过程进行了模拟分析, 探讨适宜的节水灌溉模式。结果表明, 表征土壤水分实测值与模拟值精度关系的Nash-Suttcliff效率系数Ens为0.652~0.903, 均大于0.5, 模型效果良好; 在灌水量为520 mm的传统灌溉模式下, 1.6 m土层深层土壤水分无效渗漏量为189 mm, 占地表总入渗补给水量的22.3%, 土壤水分无效渗漏大, 且与降雨和灌溉关系密切; 根据作物水分供需状况及土壤水分状况得出夏玉米、冬小麦季的灌溉量分别为50 mm、320 mm, 比传统灌溉模式共节水100 mm。改进后的灌溉模式对于土壤水分渗漏具有良好的控制作用, 土壤水分渗漏峰值明显降低, 根据作物供需与土壤水分状况提出的节水灌溉模式能减少土壤水分渗漏, 提高灌溉水利用效率。

     

    Abstract: With the industry and agriculture development, water shortage is more and more serious. Water-saving irrigation plays an important role in meeting water resources shortage problems. Water-saving agriculture and improvement of irrigation water use efficiency are developing directions of agriculture. It is important to formulate reasonable crop irrigation system based on the crops water requirement and supply for water-saving irrigation and water resources planning. In this study, soil water content and leakage, water requirement of winter wheat and summer maize rotation system in Qingdao were investigated through simulating field water movement with Hydrus-1D model based on the long term field experiment. According to the water supply and requirement of two crops, suitable irrigation amount and time were discussed. The results showed that the Nash-Suttcliff simulation coefficients Ens of measured and simulated soil water content in 20 cm, 40 cm, 60 cm, 100 cm and 160 cm depths were 0.652, 0.857, 0.852, 0.887 and 0.903 respectively, meaning the model worked well. Human influence resulted in relative worse simulation result in surface soil water content. Under conventional irrigation management with 520 mm irrigation, soil water leakage to 1.6 m depth was 189 mm, about 22.3% of the total amount of irrigation and precipitation. The soil water leakage was serious under conventional irrigation mode, and positively correlated with precipitation and irrigation. The results showed that rainfall during winter wheat growing season was only 61.6 mm, 24.5% of evaportanspiration. There was 300 mm water shortage during winter wheat growing season in the study year. During summer maize growing season, rainfall got up to 93.1% of water requirement of maize. However, complementary irrigation was needed at seeding to seedling and later growth stages due to uneven season distribution of rainfall. The improved irrigation scheme was established based on water supply and demand of summer maize and winter wheat. The irrigation amounts were 50.0 mm and 320.0 mm for summer maize and winter wheat, respectively, 100 mm less than that under conventional irrigation. Water-saving irrigation modes based on the relationship of water supply and demand greatly improved the utilization efficiency of irrigation, and decreased water leakage amount.

     

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