残膜量及分布对一维土柱水分蒸发的影响

Effect of film amount and distribution on water evaporation in one-dimensional soil column

为探究残膜量及残膜分布对土壤水分蒸发的影响效应,采用室内一维土柱试验,设计8种(0、39.6、79.2、158.4、264、396、792、1 320 kg/hm^(2))残膜量处理在土壤中平均和逐层递减2种残膜分布特征,对不同处理累计蒸发量进行监测,分析残膜量及其分布,并对蒸发过程的影响并进行模型拟合。结果表明:各处理单位时间内土壤累积蒸发量整体随残膜量的增加而减小,当残膜量高于79.2 kg/hm^(2)时,土壤累积蒸发量较无残膜处理显著减小(P<0.05)。蒸发前期残膜逐层递减分布的累积蒸发量大于平均分布,蒸发中后期残膜逐层递减分布的累积蒸发量小于平均分布。综合考虑,残膜量少于79.2 kg/hm^(2)在土壤中平均分布尚不显著影响土壤水分蒸发的极限值。本文结果可为残膜面源污染土壤水分运动规律研究提供理论参考。

In order to explore the influence of residual film amount and residual film distribution on soil moisture evaporation, an indoor one-dimensional soil column test was designedincluding 8 levels of residual film(0,39.6,79.2,158.4,264,396,792,1 320 kg/hm^(2)) with two kinds of distribution of(residual film uniformly distributedin the soil profile and gradually decreasing layer by layer).The cumulative evaporation in different situations was monitored, and the influence of residual film amount and distribution on the evaporation process was analyzed and the model was fitted.The results showed that the cumulative soil evaporation per unit time of each treatment decreased with the increase of the residual film amount.When the residual film amount was higher than 79.2 kg/hm^(2),the soil cumulative evaporation decreased significantly compared with the treatment without residual film(P<0.05).In the early stage of evaporation, the cumulative evaporation of the residual film layer-by-layer decreasing distribution was greater than the average distribution, and in the middle and late evaporation period, the cumulative evaporation of the layer-by-layer decreasing distribution was smaller than the average distribution.Overall, the residual film amount which is less than 79.2 kg/hm^(2) evenly distributed in the soil does not significantly affect soil water evaporation.Our result provides a theoretical reference for the research on the water movement law of the residual film surface source polluted soil.