Watershed Management Sciences and Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Noor, 46417-76489, Iran.
Environ Monit Assess. 2023 Jun 19;195(7):860. doi: 10.1007/s10661-023-11446-9.
The soil freeze-thaw process is a transition phase of soil water in cold areas that influences the soil's hydrological behavior. However, dynamic phenomena and corresponding consequences have yet to be studied adequately. Therefore, the present study was planned to comparatively analyze the effects of a freezing-thawing cycle on the hydrologic behaviors of loess soil from northeast Iran. Small-size (0.5 × 0.50 m) erosion plots were subjected to a freezing-thawing cycle under governing conditions of the region of the origin soil. The plots were subjected to a freezing-thawing treatment by inducing cold air until the temperature declined to below - 20 °C and lasted for 3 days using a cooling compartment system and then were kept in the laboratory with an ambient temperature of above 10 °C for 2 days. The treated plots and untreated plots were then exposed to a simulated rainfall with an intensity of 72 mm h and 0.5 h duration while they were placed on a slope of 20%. The results indicated that the hybrid processes of freezing-thawing and splash and inter-rill erosions significantly increased runoff generation and soil loss. The time to runoff, runoff volume, and soil loss were 1.65 times less and 1.38 and 2.90 times more, respectively, compared to those reported for the control treatment with significant differences (p < 0.006). The performance of ice lenses, freezing fronts, and the creation of near-saturation moisture after completing the cycle were identified as the most critical factors affecting the different soil behaviors under the frozen-thawed cycle.
土壤冻融过程是寒冷地区土壤水分的过渡阶段，影响土壤的水文行为。然而，其动态现象和相应的后果还没有得到充分的研究。因此，本研究旨在比较分析冻融循环对伊朗东北部黄土土壤水文行为的影响。小尺寸（0.5×0.50 m）侵蚀样地在控制土壤起源区条件下经历了冻融循环。通过使用冷却室系统将冷空气引入直至温度降至低于-20°C 并持续 3 天，对样地进行冻融处理，然后在温度高于 10°C 的实验室中放置 2 天。然后，将处理过的样地和未处理的样地暴露在强度为 72 mm h 和持续时间为 0.5 h 的模拟降雨中，同时将它们放置在 20%的坡度上。结果表明，冻融和溅蚀及沟间侵蚀的混合过程显著增加了径流量的产生和土壤流失。与对照处理相比，径流量、径流量和土壤流失的时间分别减少了 1.65 倍，分别减少了 1.38 倍和 2.90 倍，差异显著（p < 0.006）。冰透镜、冻结前缘和循环完成后接近饱和水分的形成被确定为影响冻融循环下不同土壤行为的最关键因素。
