积雪与地表联合覆盖条件下冻融土壤水盐运移规律

为探索石河子灌区冻融季节积雪与地表联合覆盖条件下土壤水盐运移的变化规律,2015—2016年通过田间小区试验,进行了秸秆、地膜、活性炭3种地表覆盖和裸地对照在整个季节性冻融期土壤水盐时空动态变化规律研究。结果表明;地表覆盖比裸地具有更好的保墒、降盐效果。冻结土壤完全融通后,秸秆、活性炭覆盖出现含水量增幅的最大土层范围分别是0—30,0—40cm,反映出这2种覆盖经历冻融过程后更有利于土壤水分的保持和融雪水的高效利用;活性炭、秸秆、地膜覆盖和裸地在0—30cm土层含盐量相比初始值的增幅分别为18.08%,20.30%,30.91%,32.81%,可见活性炭覆盖下抑制盐分向上运移效果最为显著,秸秆覆盖次之;经历冻融过程,土壤水分和盐分变异性随土壤深度的增加而呈现递减趋势。

A Study on Water and Salt Movement Law of Freezing and Thawing Soil under Snow and Surface Coverage

In order to explore the changing rules of soil water and salt movement under the condition of snow cover and surface mulching during the freezing and thawing season in Shihezi irrigation areas,we conducted a field plot test during 2015-2016 and investigated the temporal and spatial dynamic rules of water and salt in the soil with three different surface coverings,i.e.straw,plastic film,activated carbon,and bare land,during the whole seasonal freezing and thawing period.The results suggested that surface coverage was more effective in the preservation of soil moisture and salt reduction than the bare land.After the frozen soil was fully thawed,the deepest soil layer in which the water content increased was 0-30 cm and 0-40 cm for the soil covered with straw and activated carbon,respectively,indicating that the two kinds of coverings were more beneficial to the maintenance of soil moisture and the efficient use of snowmelt water after the freezing and thawing process.Compared with the initial value,the increase in salt content in the 0-30 cm soil layer in the soil covered with activated carbon,straw,plastic film,and bare land was 18.08％,20.30％,30.91％,and 32.81％,respectively,suggesting that the inhibition effect on the upward movement of salt by activated carbon coverage was the most significant,followed by straw mulching.During the process of freezing and thawing,the variability of soil moisture and salinity showed a decreasing tendency with the increasing of soil depth.