漓江上游猫儿山3种典型植被不同层次土壤的含水量

目的]揭示漓江上游森林植被对降水产流的调节作用,客观评估漓江上游水资源潜力,为流域水资源管理和森林经营提供科学依据。方法]以漓江上游猫儿山林区的毛竹林(Phyllostachys pubescens)、荷木林(Schima superba)和杉木林(Cunninghamia lanceolata)3种典型森林植被为研究对象,比较不同层次土壤含水量及其影响因素。结果](1)由于荷木林冠层结构复杂,与毛竹林和杉木林相比,荷木林蓄水能力更强;毛竹林、荷木林和杉木林3种植被垂直结构明显,导致土壤含水量垂直变化趋势不同;(2)荷木林土壤含水量都在高值变化,而杉木林土壤含水量都在低值变化;各层次土壤含水量与年降雨分配关系密切,随着雨旱两季变化,毛竹林、荷木林和杉木林不同层次土壤水分随降雨变化趋势基本一致;(3)毛竹林土壤孔隙度大于木荷林和杉木林,但毛竹林的浅根性和速生性对表层土壤水含量影响更大。结论]大气降水是土壤含水量变化的主要因素,土壤含水量是降雨与植被垂直结构及蒸腾作用共同作用的结果。

Soil Water Content Under Three Typical Forests of Mao'er Mountain in Upper Reaches of Lijiang River

Objective] Studying relationships between forest vegetation and its hydrological effects, and evaluating the water resources potential in the upper reaches of Lijiang river in order to provide scientific basis for water resources management and forest management.Methods] Changes of soil water content at different soil layers in three typical forests including Phyllostachys pubescens, Schima superba and Cunninghamia lanceolata were studied in Mao''er mountain in the upper reaches of Lijiang River.Results] (1) Due to the complicated canopy structure, higher water storage was found in S. superba. There was an obvious difference in the vertical variation of soil water content in different soil layers because of the vertical vegetation structure. (2) Soil water content in S. superba varied within higher values, while it changed within lower values in C. lanceolata. Soil water content at different soil layers significantly correlated with the precipitation, and the three typical forests showed a same changing trend with annual rainfall. (3) Soil porosity in P. pubescens was higher than that in S. superba and C. lanceolata and its property of shallow root and fast growing exerted great effects on surface soil water content.Conclusion] Precipitation is the most important factor that influence soil water content, and the variation of soil water content is the result of rainfall and vertical vegetation structure and transpiration.