青海湖北沙柳河镇土壤水与土壤水库研究

Soil Moisture and Its Distribution Characteristics at Shaliuhe Town in North Qinghai Lake

根据土壤含水量和粒度测定,对青海湖北侧沙柳河镇附近土壤含水量与土壤水库进行了研究。结果表明:青海湖北侧土壤含水量随着深度的增加而减少,在0.6m深度以下土壤含水量严重不足;该区土壤水库蓄水性非常特殊,上部蓄水量多,下部蓄水量少。该区土壤厚度小,土壤水库容量小,蓄水能力小,干旱年易于发生草原退化。沙柳河镇土壤水集中分布在土壤的上部,初步认为这是该区土层冻结期较长和低温导致蒸发作用较弱决定的,这对该区根系较浅的草原植被的生长发育是非常有利的。在近年降水增多条件下,该区土壤水分能够满足草原植被的生长。该区不适于发展乔灌木植被,适合发展根系短、耗水较少的草原植被。

The Qinghai Lake area is sensitive to climatic changes and has fragile ecological environment.This paper aims at researching on soil moisture distribution and soil granularity,evaluating the storage and regulating capacity of soil reservoir,analyzing the types of water cycle and vegetations suitable for developing and providing theoretical basis for husbandry production,vegetation construction and policy formulation around the Qinghai Lake.With soil samples collected at Shaliuhe Town in the north of Qinghai Lake,we have analyzed the characteristics of soil moisture distribution and soil granularity based on the measurement of soil moisture content and soil granularity.The results show that with the increasing depth of water in the north of Qinghai Lake,the soil moisture decreases and the degree of the dried soil layer aggravates;the soil moisture distribution in this area is extremely special because the soil moisture is high in the upper soil layer while low and seriously inadequate in the lower;the soil particle size is mainly coarse silt slightly bigger than that at Loess Plateau;soil moisture below 0.6m is less than 11%,which shows that the desiccation of soil layer is significant and the precipitation doesn’t participate in groundwater circulation resulting in forming the soil-atmosphere moisture cyclic model.In addition,due to small soil thickness,low capacity of soil reservoir,little storage capacity and poor hydrological adjusting functions,the ecological environment is fragile in this area and grassland degradation easily occurs in drought years.Moreover,because of the long freezing period of soil layer and the phenomenon that low temperature results in the poor evapotranspiration,soil moisture is mainly distributed in the upper soil layer.In summary,this region is favorable to develop shallow-rooted grassland vegetations and little water-consumption grassland vegetations but not suitable for developing the plants of high water consuming intensity or arbor and bush vegetations.