毛乌素沙地樟子松林恢复过程的土壤有机质含量变化特征

Change Characteristics of Soil Organic Matter in the Recovery Process of Pinus sylvestris var. mongolica in Mu Us Sandy Land

为明确毛乌素沙地樟子松林恢复过程的土壤有机质含量变化特征,采用时空互代的方法,以裸地为对照,选择立地条件相似的分别种植于1960s,1970s,1980s的樟子松林土壤作为研究对象,研究了林下土壤有机质含量随恢复年限的变化规律和垂直变化特征,并进一步分析了其丰缺度。结果表明:(1)不同恢复年限樟子松林土壤有机质含量呈现随土层深度的增加逐渐降低的现象,即具有明显的表层富集特征。(2)随着林龄的增加樟子松林中土壤有机质含量变化存在先增加后减小的变化趋势,但变化幅度逐渐减小。(3)相比于裸地,研究区不同恢复年限樟子松林均提高了土壤有机质含量,但总体上土壤有机质含量仍处于缺乏水平。

In order to understand the change characteristics of soil organic in the recovery process of Pinus sylvestris var.mongolica in Mu Us sandy land,we used the space-for-time substitution method and took the bare land as a contrast,the Pinus sylvestris var.mongolica communities afforested in 1960 s,1970 s and 1980 s under similar site condition were selected as the sites.The temporal changes and vertical variation characteristics of soil organic matter contents in Pinus sylvestris var.mongolica forest lands were studied,and abundance and deficiency status were further analyzed.The results showed that:(1)the contents of soil organic matter of lands with different years of Pinus sylvestris var.mongolica growth decreased gradually with the increase of soil depth,showing the obvious surface enrichment;(2)the soil organic matter content in Pinus sylvestri var.mongolica forest increased first and decreased later with the increase of forest age,but the change range gradually decreased;(3)the contents of soil organic in Pinus sylvestris var.mongolica forests with different recovery years in the study area increased compared with the bare land,but the contents of soil organic matter were still at the deficient level on the whole.