保水剂对砂壤土水分二维入渗的影响

为揭示保水剂用量对有覆砂与无覆砂条件下土壤水分二维入渗的影响和规律,以裸土试验组为对照,通过模拟单点源入渗试验,研究在覆砂与无覆砂条件下保水剂用量(0、0.1%、0.2%、0.5%)对土壤水分入渗过程的影响.结果表明:两种不同条件下的土壤水分入渗规律基本一致.在入渗初期,随着保水剂用量的增大,入渗速率越小,累积入渗量越大,湿润锋在水平与垂直方向上的推移以及湿润体横纵比的差异均不显著;入渗中期的入渗速率和累积入渗量规律与入渗初期一致,但湿润锋在水平方向上的推移增大,而垂直方向上的推移减小,湿润体的横纵比增大;入渗后期,入渗速率基本趋于稳定,累积入渗量继续增大.Kostiakov入渗模型可以反映保水剂对砂壤土水分二维入渗的规律性.

Effect of water retaining agent on two-dimensional infiltration of sandy loam soil moisture

In order to reveal the effect of amount of water-retaining agent on the two-dimensional infiltration of water into soils with and without sand cover, this study took a bare soil test group for comparison, the effects of different water-retaining agent dosage (0, 0.1%, 0.2%, 0.5%) on soil water infiltration under conditions of sand cover and non-sand cover were studied through a simulated single-point source infiltration experiment. The results show that the regularity of soil water infiltration under the two different conditions is basically the same. In the early stage of infiltration, with the increase of the amount of water-retaining agent, the smaller the infiltration rate is, the greater the cumulative infiltration is. The difference between the horizontal and vertical movement of the wetting front is not significant, while the horizontal and vertical ratio of the wetting body is not significant as well. The infiltration rate and cumulative infiltration in the middle stage of infiltration are consistent with those in the initial stage of infiltration, but both the horizontal ratio and vertical ratio of the wetting body increase in the horizontal direction and decrease in the vertical direction as a contrast. In the later stage of infiltration, the infiltration rate basically tends to be stable, and the cumulative infiltration continues to increase. The Kostiakov infiltration model can characterize the regularity of two-dimensional infiltration of water into sandy loam by the water-retaining agent.