宽垄沟灌土壤水分累积入渗特性试验研究及模拟

Experimental study and simulation on cumulative infiltration characteristics of soil water under wide ridge furrow irrigation

为了探究宽垄沟灌土壤水分累积入渗变化特性,在大田试验的基础上,利用HYDRUS-2D软件模拟并结合理论分析和数值模拟的方法,重点研究了单宽入沟流量为0.5 L/(s·m),灌水15 min后,宽垄沟灌不同沟宽(40,50,60 cm)与沟深(20,25,30 cm)对宽垄沟灌土壤累积入渗量随时间变化的影响.结果表明:沟深一定时,沟宽60和50 cm时累积入渗量较沟宽40 cm时分别增加了21.88%和7.88%,即沟宽越大,累积入渗量越大;沟宽一定时,沟深30和25 cm时累积入渗量较沟深20 cm时分别减少了3.80%和2.05%,即沟深越大,累积入渗量越小.在电容充电模型基础上建立了宽垄沟灌不同沟宽与沟深条件下的累积入渗量计算模型,累积入渗量与时间呈指数函数关系,并利用试验数据对计算模型进行了验证,模型的计算精度较高.研究结果可为改进宽垄沟灌灌水技术提供参考.

To investigate the characteristics of soil moisture accumulation and infiltration changes under wide ridge furrow irrigation,on the basis of field experiment,the effects of different groove width(40 cm,50 cm,60 cm)and ditch depth(20 cm,25 cm,30 cm)on the cumulative infiltration with time were studied by using HYDRUS-2D software simulation combined with theoretical analysis and nume-rical simulation,focusing mainly on the single width flow rate into ditch(0.5 L/(s·m),15 min after irrigation).The results show that when the ditch depth was constant,the cumulative infiltration of 60 cm and 50 cm ditch width is higher than that of 40 cm ditch width,increasing by 21.88%and 7.88%respectively.The larger the groove width,The greater the cumulative infiltration.When the groove width was constant,the cumulative infiltration of 30 cm and 25 cm ditch width is lower than that of 20 cm ditch width,decreasing by 3.80%and 2.05%respectively,compared with 20 cm.The larger the ditch depth,the smaller the cumulative infiltration.On the basis of the capacitive charging model,the calculation model of cumulative infiltration under the condition of different groove width and depth is established,and the relationship between cumulative infiltration and time is an exponential function,and the calculation model is verified with high precison by utilizing test data.The results can provide reference for improving wide ditch infuse water technology.