青海湖克土沙区不同类型沙丘土壤水分的动态变化

对青海湖湖东克土沙区的土壤水分变化特征及其与降雨之间的关系进行了分析,结果表明:固定沙丘土壤水分随深度的变化较小,采取措施(人工植被+麦草方格沙障)的流动沙丘在不同深度上的变异最大;从0—80cm平均水平看,土壤含水量为固定沙丘>流动沙丘>采取措施的流动沙丘;三种沙丘土壤水分与降雨的时间变化都基本一致,可以分为冻结滞水期(12月—翌年3月)、水分补偿期(4—7月)和失水期(8—11月)三个阶段,土壤含水量以夏秋季最高;降水对0—80cm的土壤水分都有影响,对上层土壤的影响更显著,采取措施的流动沙丘主要影响深度为60cm,固定沙丘为20cm;在流动沙丘上种植人工植被以及布设麦草方格沙障,可以抑制表层土壤水分蒸发,提高表层土壤含水量,在植被恢复前能够有效减少风蚀,对于植物初期生长具有积极意义。

Dynamic Changes of Soil Moisture in Different Dunes of Ketu Sand Land in Qinghai Lake Basin

In this paper,we selected three kinds of dunes in Ketu sand land on the east of Qinghai Lake,analyzed the soil moisture,as well as correlations between soil moisture and rainfall.The results show that: soil moisture in fixed dune has less variation along the profile,whereas the largest variation of soil moisture along the profile was observed in active dune with artificial measures(artificial vegetation and straw checkers).During the observation periods,soil moisture of the fixed dune was the highest in 0—80 cm depth,followed by active dune,and active dune with artificial measures.The three kinds of dunes have similar temporal variation trends,which can be divided into three stages such as freezing stagnation period(from December to next March),compensation period(from April to July) and dehydration period(from August to November).Soil moisture is the highest in summer and autumn.The impact of precipitation on the upper soil is more significant,which mainly influences 60 cm depth in the active dune with artificial measures,20 cm depth in the fixed dune.In addition,our research suggests that the artificial vegetation and straw checkers can inhibit surface soil moisture evaporation,improve surface soil moisture and reduce wind erosion,which is quite important for the initial growth of vegetation before the dune is fixed.