利用线源入流测量方法对土壤入渗影响因素的研究

Effects of linear-source measurement method on the soil infiltration process

土壤入渗过程是农田水分循环的重要组成部分,其准确测量对设计与管理灌溉系统、研究降雨产汇流过程等有重要意义。土壤入渗过程受土壤本身及地表情况等很多因素的影响。本文利用线源入流测量方法研究了土壤初始含水量与地表坡度对土壤入渗过程的影响。室内试验选用壤土,设计了3组初始含水量(风干土、8.22%和16.3%)和3组地表坡度(0°、5°和15°),观测得到较为准确的土壤初始入渗过程。试验结果发现:3组含水量中8.22%的处理土壤入渗性能最高,稳定入渗率为39.8 mm·h^-1;土壤坡度对入渗过程的影响不大,3组坡度的土壤稳定入渗率分别为43.1、51.7 mm·h^-1和52.8 mm·h^-1。分析认为可能由于土壤太高或太低的含水量会导致水力梯度的降低或土壤团聚体的破坏而降低土壤入渗率。土壤初始含水量对入渗过程的影响还需在不同土壤类型进行试验而得到验证。

Soil infiltration is an important part of water cycle.Accurate measurement of the soil infiltration process is of great importance for the irrigation management to study this process.Soil infiltration influenced by many factors such as soil properties and surface condition.In this study,the linear-source measurement method for soil infiltration was used to discuss the effects of initial soil water content and slope on the soil infiltration process.Lab experiments were conducted with loam soil.Three initial soil water contents(air-dry soil,8.22%and 16.3%)and three surface slopes(0°,5°and 15°)were selected in this study.The measured soil infiltration rates were fitted with the Philip Infiltration Model.The results showed that a critical soil water content related to the maximum soil infiltrability existed,the stable infiltration rate was 39.8 mm·h^-1.There was no obvious effect of slope on the soil infiltration according the results in this study,the stable infiltration rate of three surface slopes were 43.1、51.7 mm·h^-1 and 52.8 mm·h^-1.Too high or too low soil water content decreased soil infiltrability due to higher soil water content lowered the hydraulic gradient,while soil aggregates might be destroyed with lower soil water content.More experiments were needed to verify this conclusion.The initial soil infiltration process was observed in this study,so the discussions about the effects of soil water content and slope were more convincing.