四川盆地西缘山地典型地段不同林分对土壤质量的影响

以四川盆地西缘山地典型地段的桦木林、柳杉林、杉木林、竹林和天然常绿阔叶为研究对象,从土壤剖面特征、土壤机械组成、酸碱性和土壤养分含量等方面对比分析了林地土壤质量。结果显示:牛尾竹林土壤各项指标处于较低水平,土壤质量很差;人工栽植的针叶林(柳杉林),其人工林土壤表现出很好的发育和熟化特征,其有机质含量和速效N、P、K总量也仅次于天然林,且团聚体数量较多,但水稳性能较差,表土的养分淋溶特征明显;而盐基交换量和盐基饱和度以桦木幼林最大,其次为天然常绿阔叶林、竹林、杉木林,最小为柳杉林。表明以木材为主要经营目标的人工针叶林(柳杉林和杉木林)加速了盐基离子的流失,最终导致了土壤的酸化,因此合理的植被构成及林分经营模式是维持土壤质量的关键技术。

Effect of Different Forests on the Soil Quality of Typical Sections on the Western Mauntainous Margins of the Sichuan Basin

In this paper according to the feature of soil profile,mechanical composition,value of pH,nutrient content,a comparatire analysis was made of the soil quality of five forest stand types including Cryptomeria fortunei forest,Cunninghamia Lanceolata forest birch forest,bamboo forest and natural evergreen broad-leaved forest.The results showed that the bamboo forest soil was at a low level in all the above indicators.The coniferous forest soil（Cryptomeria fortunei,Cunninghamia lanceolata） showed well-developed and ripening characteristics;the contents of aggregate structure organic matter and N,P,K in the soil of these two forests were also second only to those in the soil of natural evergreen broad-leaved forest.The eluvial characteristic of nutrients in the surface soil was obvious,and the capacity of the water erosion resistance was very poor.The exchange capacity and saturation degree of their base were as follows：young birch forestnatural evergreen broad-leaved forest bamboo forest Cunninghamia Lanceolata forstCryptomeria fortunei forest.In conclusion,the exchange capacity and saturation degree could accelerate the losing of base ions and cause the acidification of soil.So the crucial technology for maintaining the soil quality are the rational vegetation composition and vegetation management patterns.