高寒草甸次生裸地的植物群落特征及土壤水分的季节变化

为恢复和改造高寒地区严重退化的草地，基于对黄河首曲玛曲县“水蚀型”次生裸地植被和土壤水分的调查，研究了其植物群落特征及土壤水分的季节变化规律。结果表明，“水蚀型”次生裸地植物群落以杂草类为主，结构简单，种类单一，盖度低，分布稀疏，群落的垂直结构分层不明显，地面芽植物占优势；“水蚀型”次生裸地土壤水分随着降水变化而呈现季节性变化，5―11月0~20和20~40 cm土层土壤水分均呈先升高后降低的变化趋势，最大值出现在7―8月，最小值出现在5月和11月。“水蚀型”次生裸地由于土壤松散、植被覆盖低，其土壤保水效果远不及轻度退化草地。

A study on community characteristics and soil moisture variation in alpine meadow secondary bare land

In order to restore and reconstruct the severely degraded grassland of Maqu alpine regions, the community characteristics and soil moisture variation were studied based on investigation of vegetation and soil moisture in “water erosion type” secondary bare lands of Maqu country (the first bend of the Yellow River). The results showed that the vegetation community in “water erosion type” secondary bare lands was mainly dominated by weeds and with characteristics of simple structure, single type, low coverage, sparse distribution, obscure vertical structure of community and dominant aboveground buds. The soil moisture showed a seasonal change with of change precipitation. The soil moisture in 0~20 cm and 20~40 cm soil layers was increased firstly and then decreased from May to November, and the maximum value appeared in July to August and the minimum value in May and November. These findings suggest that due to loose soil structure and low vegetation coverage, effects of water conservation on “water erosion type” secondary bare land are far less than that on the light degraded grassland.