微咸水矿化度与滴头流量对土壤湿润体的影响与模拟

Influence and Simulation of Brackish Water Salinity and Emitter Discharge on Soil Wetting Volume

为了分析不同微咸水矿化度和滴头流量对滴灌土壤湿润体的影响,在室内进行了不同微咸水矿化度(0、1.7、3、4和5 g/L)和不同滴头流量(7、9和11 m L/min)条件下滴灌入渗试验。试验结果表明:不同流量和不同矿化度下滴灌湿润锋形状相似,均为1/4椭圆形,湿润锋随着时间增大而增大;滴头流量越大,水平湿润锋推进越快,随着矿化度增大,水平湿润锋最大推进距离先减小后增大,垂直湿润锋最大推进距离先增大后减小;不同微咸水矿化度和滴头流量下土壤湿润锋均可采用椭圆方程拟合,并在分析微咸水矿化度、滴头流量和时间对椭圆方程参数A和B的影响基础上,建立了微咸水矿化度和滴头流量耦合条件下滴灌土壤湿润锋动态变化模型,并采用试验数据进行验证,结果表明训练集模型的MAE和RMSE分别为0.390和0.549,验证集模型的MAE和RMSE分别为0.438和0.635,表明模型有较高的计算精度,可以用于微咸水矿化度和滴头流量耦合下的湿润体动态模拟。

In order to analyze the influence of different salinity and dripper flow on soil wetting body,the experiments of drip irrigation under the conditions of different salinity (0,1.7,3,4,5g/L)and different dripper flow (7,9,11mL/min)were carried out in this paper.The results show that the wetting front of drip irrigation with different emitter discharge and different brackish water salinity is similar in shape, which is 1/4 ellipse,and the wetting front increases with time;the greater the emitter discharge,the quicker the horizontal wetting front advances;with the increase of salinity,the maximum advancing distance of the horizontal wetting front decreases first and then increases, and the maximum advancing distance of the vertical wetting front increases first and then decreases;the wetting front of soil with different salinity and dripper flow can be fitted with elliptical equation.On the basis of analyzing the influence of salinity,dropper flow and time on the parameters A and B,the dynamic change model of soil wetting front in drip irrigation under the coupling condition of salty water salinity and dripper flow is established.Then the experimental data are used to verify the results.The results show that the MAE and RMSE of the training set model are 0.390and 0.549,respectively;the MAE and RMSE of the validation set model are 0.438 and 0.635,respectively.This indicates that the model has higher calculation accuracy and can be used for the dynamic simulation of drip irrigation soil wetting under the coupling of brackish water salinity and dripper flow.