红壤积水入渗及土壤水分再分布规律室内模拟试验研究

Study on Ponded Water Infiltration and Soil Water Redistribution in Red Soil

利用室内模拟土柱试验研究了红壤积水入渗及土壤水分再分布规律。结果表明:入渗过程中湿润锋距离、累积入渗量与时间的平方根呈线性关系,湿润锋运移速率与时间呈乘幂关系,而入渗率与时间平方根的倒数呈线性关系;再分布过程中,在隔绝蒸发条件下,土壤含水量随土层深度的增加而下降,同一深度土层含水量则随时间推移而下降。无论在隔绝蒸发还是在自然蒸发条件下,短期内土壤水吸力有随土层深度的增加呈先下降后升高的趋势,而同一深度土层水吸力则随时间的推移而升高;土壤初始含水量对水分的入渗及再分布有较大影响,初始含水量较低时,水分入渗较快,而水分再分布则较慢。

Laws of water infiltration and soil water redistribution in red soil were studied through indoor soil column simulated experiments. During infiltration period, the depth of wetting front and the infiltration volume had a linear relation with the square root of time, the velocity of wetting front had a power relation with time, and the infiltration rate had a linear relation with the reciprocal of the square root of time. During redistribution period, soil water content decreased with soil depth, and soil water content at the same depth decreased with time under preventing evaporation conditions. Regardless of preventing evaporation or not, soil water suction decreased firstly and then increased with the increase of soil depth, and soil water suction at the same depth increased with time. In addition, the original soil water content significantly influenced infiltration and redistribution. The lower the original soil water content was, the quicker the water infiltrated and the slower the water redistributed.