中国农业机械化科学研究院集团有限公司 主管

北京卓众出版有限公司 主办

小麦中后期田间微喷灌土壤水分运移模拟分析

Simulation Analysis of Moisture Movement in Wheat Field Micro-sprinkler Irrigation

  • 摘要: 针对小麦中后期微喷灌湿润区域分布特点,探讨了小麦专用微喷带在不同灌溉影响因素下小麦中后期根区土壤水分运移与分布规律。通过试验测量了微喷带在不同灌溉压力下灌水强度,将有效湿润区域划分为4个子区域,得出不同灌水强度作为灌溉边界条件。考虑小麦根系吸水情况下,建立微喷灌土壤水分运动方程及求解条件。利用HYDRUS-2D模型进行微喷灌数值模拟,通过对比分析模拟结果和试验数据,证明数值模拟能够有效反应土壤含水率分布情况。对微喷带在不同灌溉压力、不同灌水下限和不同铺设间距影响因素下进行模拟分析,结果表明:在灌溉压力0.15 MPa时,有效湿润区域大且水分分布满足小麦根系需求;以田间持水量的60%作为小麦灌水下限,有利于降低微喷带铺设成本、节约灌溉水量和提高灌水利用率;在铺设间距440 cm时,根部土壤水分分布呈一条均匀带状且均匀度都在90%左右。本研究可为小麦专用微喷带铺设与运行提供合理作业参数,同时为小麦节水灌溉提供理论参考。

     

    Abstract: According to characteristics of moisture distribution of micro sprinkler irrigation in the middle and late stage of winter wheat,soil moisture movement and distribution in the root zone of wheat in the middle and later stages of wheat were discussed under different irrigation factors.Irrigation intensity under different irrigation pressure was measured by experiment.Effective humid region was divided into four sub-regions,and different irrigation intensity was obtained as irrigation boundary condition.Considering water absorption of winter wheat roots,equations of micro-sprinkler irrigation soil water movement and solving conditions were established.By comparing and analyzing simulation results and experimental data of micro-spray irrigation,HYDRUS-2D numerical simulation was proved to be effective in soil moisture distribution.On the basis of this model,influence factors of different irrigation pressure,different irrigation lower limit and different laying distance of micro-spray belt were simulated and analyzed.Results showed that effective wet area was large and water distribution could meet demand of wheat root system without water waste under irrigation pressure of 0.15 MPa;taking 60% of field water capacity as lower limit of irrigation was beneficial to reduce laying cost of micro spray belt,save irrigation water and increase utilization rate of irrigation;at interval of 440 cm,soil moisture distribution in the root was a uniform band,and uniformity was about 90%,which could make each wheat get the same irrigation water quantity.Above results could not only provide reasonable operation parameters for laying and running of micro-spray belt,but also provide theoretical reference for water-saving irrigation of wheat.

     

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