不同植被类型对土壤物理化学和力学性质的影响

目的]分析不同植被类型对土壤物理化学和力学特性的影响,揭示植被多样性对土壤及生态环境的响应,为区域生物工程和生态环境修复提供理论依据。方法]以青海省西宁盆地黄土区和互助北山森林区为研究对象,通过室内试验测定土体的物理化学和力学性质,探讨不同植被类型对土壤物理化学和力学性质的影响。结果]植被类型的多样性对植被覆盖度的影响较大,且不同植被组合类型与根-土复合体含水量与植被覆盖度呈正相关,与土壤孔隙度呈负相关,其中随植被多样性的增加,土壤含水量增加8.88%~22.43%,土壤密度增加0.03~0.54 g/cm3,孔隙率降低4.89%~13.38%,根土层p H趋于弱酸性;同一区域土壤养分含量和根-土复合体黏聚力总体表现为乔灌草组合区﹥草灌区﹥草本区,说明植被类型、枯枝落叶及根系等对土壤养分的积累和表层土壤力学特性的影响较大。结论]植被类型的多样性在改善生态环境方面起到积极作用,采用植被护坡和生态环境保护方面应考虑植被类型的多样性,实现植被-土壤-环境的良性循环。

Effects of Different Vegetation Types on Soil Physical and Chemical and Mechanical Properties

Objective]To study effects of different vegetation types on soil physical and mechanical properties and nutrient contents,and it re-veals the response of vegetation diversity to soil and ecological environment,and provides theoretical basis for the restoration of regional biological engineering and ecological environment.Method]Taking the loess area of Xining Basin and the mutual-aid Beishan forest area in Qinghai Prov-ince as the research object,the physicochemical and mechanical properties of soils were analyzed with a combination of in situ and indoor testing, the effects of different vegetation types on soil physical and mechanical properties and nutrient contents were discussed.Result]The diversity of vegetation types had a great influence on the vegetation coverage,and there was a positive correlation between the vegetation types and moisture content of the root-soil composite and the vegetation coverage,but negatively correlated with the soil porosity,the soil water content increased with the vegetation diversity ranged from 8.88% to 22.43%,the soil density increased from 0.03 to 0.54 g/cm3,and the porosity decreased from 4.89% to 13.38%.The pH of the soil layer tended to be weakly acidic.In the same area,soil nutrient content and cohesion of root-soil composite generally showed as follows:Arbor-shrub-grass combination area>shrub-grass area>grass area,This showed that vegetation types,litter and roots had a great influence on soil nutrient accumulation and surface soil mechanics characteristics.Conclusion]The diversity of vegetation types plays an active role in improving the ecological environment,and the diversity of vegetation types should be considered in vegetation slope protection and ecological environment protection so as to realize the virtuous circle of vegetation-soil-environment.