残膜对土壤水分渗吸过程中湿润锋的影响

采用室内水分渗吸试验,通过设置6个残膜面积水平,分别为0.25,0.50,1.00,2.00,4.00,8.00 cm²,和4个残膜密度水平,分别为60,180,300,420 kg/hm²,以无膜作对照,共25组试验处理,分析了不同残膜密度及尺寸对湿润锋的运移的影响.分析结果显示,在容重为1.53 g/cm³的黏壤土中混入残膜加快了土壤入渗过程,起到了促渗作用;且随着残膜密度的增大,入渗历时的最大值和最小值对应的单片残膜面积随之增大,促渗效应逐渐减弱;土壤中残膜密度较低时,残膜面积对湿润锋运移深度的影响程度大于残膜密度,残膜密度较高时,残膜密度的影响力增强;单片残膜面积为0.25 cm²时,随着残膜密度的增加,入渗历时先减小后增大,在180 kg/hm²处达到最小值;在土壤中均匀混入单片面积小于等于0.25 cm²的残膜后,形成了新构土壤,具有独特的物理性质.

Effects of residual plastic film on wetting front during soil water imbibition

The indoor water infiltration test was used to analyze the influence of different residual film density and size on the migration of wetting front by setting 6 residual film size levels,namely,0.25,0.50,1.00,2.00,4.00,8.00 cm²,and 4 residual film density levels,namely,60,180,300,420 kg/hm²,and no film control treatment.The results show that the residual film can accelerate the infiltration process and promote the infiltration in 1.53 g/cm³ clay loam.With the increase of residual film density,the area of single residual film corresponding to the maximum and minimum infiltration duration increases,and the infiltration promoting effect decreases gradually.When the residual film density is low,the influence of residual film area on the depth of wetting front is greater than that of residual film density.When the residual film density is high,the influence of residual film density is enhanced.When the area of single residual film is 0.25 cm²,the infiltration duration first decreases and then increases with the increase of residual film density,reaching the minimum value at 180 kg/hm².After the residual film with a single area less than or equal to 0.25 cm² is mixed into the soil,a new soil is formed,which has unique physical properties.