黑土区坡耕地壤中流水平迁移动力学模型研究

Study on the Dynamics Model of Horizontal Migration of Interflow in Cropland in Black Soil Area

为了解决我国黑土区坡耕地犁底层影响下壤中流水平迁移动力学模型的建立问题,基于能够连续模拟犁底层上部土壤及犁底层内部土壤水分垂直迁移的Richard模型,借鉴模拟犁底层以上土壤水分水平迁移的壤中流动力波模型及'双超'模型原理,提出了适合黑土区坡耕地壤中流水平迁移的模拟机理模型,并利用人工模拟降雨试验获取实测值,分析了壤中流产生及迁移影响因素影响机理。通过试验得出:土壤质地一定条件下,坡面坡度是决定壤中流强度的关键影响因素,随着坡度的增加,壤中流强度增加显著。土壤初始含水量及降雨强度仅对产流时间影响较大,对壤中流流量大小影响较小。壤中流流量显著小于土壤表面径流,但其对土壤养分水平迁移的贡献可能高于土表径流。模型模拟值与实测值基本一致,两种坡度条件下RMSE分别为0.136 ml/min和0.138 ml/min,R^2分别为0.89,0.92,模型能够反映出存在犁底层条件下的壤中流产生情况,说明壤中流水力坡度可以近似为地面坡度,同时将犁底层入渗能力作为壤中流计算依据的假设具有一定的合理性,进一步解决了犁底层中存在土壤水分垂直入渗条件下如何利用Richard模型进行壤中流侧向出流计算问题。

In order to solve the problem of interflow model establishment in sloping farmland under the influence of plough pan in black soil region of China,we used the Richard model to simulate soil water vertical migration in and above plough pan,and then setup mechanism interflow model based on Richard model,dynamic wave model and double super model.The measured data were obtained by the artificial rainfall experiments to reveal the function of the main factors on interflow.When the soil texture is fixed,slope gradient is the key factor to determine the interflow intensity.With the increase of slope gradient,the interflow rate increased significantly.The initial soil moisture content and rainfall intensity had greater impact on interflow occurrence time,but had little effect on the runoff volume.The interflow rate was much lower than that of soil surface runoff,the contribution of the interflow to soil nutrient transfer was higher than that of soil surface runoff.The simulated data agreed with the measured data,the RMSEs were 0.136 ml/min and 0.138 ml/min,R^2 was 0.89 and 0.92,respectively.The model can reflect the interflow process.It is reasonable to assume the interflow infiltration capacity as the basis of interflow calculation in soil,which can solve the problem of how to use Richard model to calculate the lateral flow under the soil moisture vertical infiltration in the plough pan.