庐山6种树木立地土壤溶液铝形态与溶解有机碳变化

Dissolved aluminum and organic carbon in soil solution under six tree stands in Lushan forest ecosystems.

于1999年夏季,采集了庐山植物园6种树木立地的不同层次土壤样品,提取土壤溶液,分析其溶液中的溶解铝和溶解有机碳.结果表明,尽管发育于同一发生性土类,不同立地下土壤溶液溶解铝含量有明显差异,而溶解性有机碳的差异相对较小.在6种树木立地中,香柏立地表层土壤溶解铝含量达4.95mg·kg-1,为其它针叶林立地的2倍,是阔叶林立地的3倍.溶解铝积累与土壤酸化强度有密切关系。但溶解有机碳趋向于形成抑制毒性的单核铝.供试的不同立地土壤可以按溶液铝化学特点分为不同的生态化学类型.

Different depths of soils under 6 tree stands in Lushan Botany Garden were sampled and water-digested at room temperature. The dissolved aluminum and organic carbon were then determined by colorimetry, using 8-hydrox-ylquilin and TOC Analyzer, respectively. The results indicated that even derived from a naturally identical soil type, the test soils exhibited a diverse solution chemistry, regarding with the A1 speciation. The soil solutions under Japanese cedar, giant arborvitae and tea had lower pH values and higher contents of soluble aluminum than those under Giant dogwood, azalea and bamboo. Under giant arborvitae, the lowest pH and the highest content of total soluble aluminum and monomeric aluminum were found in soil solution. There was a significant correlation between soluble aluminum and DOC, which tended to depress the accumulation of toxic monomeric aluminum. The 6 tree stands could be grouped into 2 categories of solution chemistry, according to aluminum mobilization.