浑善达克沙地流沙与四种主要植物群落土壤水分时空变化的研究

Research on Temporal and Spacial Variety of Soil Moistures of Shifting Sand Dune and Four Main Plant Communities on Otindag Sandy Land

本文采用定位取样与烘干法，测定了浑善达克沙地流动沙地与平沙地四种主要植物群落土壤含水量的时空变化。结果表明：流动沙地与平沙地各植物群落土壤含水量在空间上由剖面上部而下可划分为水分活跃层、水分次活跃层和水分相对稳定层三层，水分活跃层的变化与其根系分布层密切相关，深根系的植物其水分活跃层分布较深。各样地土壤水分时间动态变化明显，整个生长季土壤水分干湿变化呈“S”形，土壤含水量按其季节变化可分为三个时期，4～5月降水贮存期，6月～9月中旬水分消耗期、9月下旬～10月水分缓慢恢复期。土壤水分的时空变化受立地条件、植被等诸多因子的影响，各样地因土壤机械组成和地表覆盖不同而引起水分在时间与空间上的分异。

The temporal and spacial variety of soil water content of shifting sand and four main plant community on Otindag sandy land was measured by orientation sampling and drying means. The results are as follows：the soil water content profiles of shifting sand nune and plant community derided into three layers from top to bottom： water active layer, subactive layer and relative stable layer. The variety of water active layer had relations with root system distribution, the water active layer distributed deeply with deep root plant. The water temporal variety of sand were notable, The dry and humid change of soil moisture of whole season present ＂S＂ shape. Based on the seasonal variation of sandy soil moisture, it can be divided into three phase： the soil moisture stocking phase from April to May, the lose phase from June to September, the slowness refilling phase from September to October. The water soil con- tent variety is mainly affected by precipitation, vegetation and site factors,the temporal and special differentce of soil water content attribute to the difference of soil mechanical composition and surfacee vegetation coverage.