植被恢复过程中土壤有机质和全氮的变化特征及区域差异

不同区域植被恢复对土壤化学性质变化的影响差异较大。本文通过收集前人在土壤化学性质方面的研究数据, 选取福建省长汀县、闽清县和陕西省陕北地区植被恢复过程中0~20 cm 表土层有机质和全氮含量,进行了两类区域土壤表层有机质和全氮在自然恢复和人为恢复过程中变化特征的比较分析。结果表明, 福建省长汀县和闽清县的植被恢复初期, 人为恢复对土壤有机质和全氮含量的影响较大, 后期自然恢复影响更大;陕北地区植被恢复初期自然恢复对土壤有机质和全氮含量的改善好于人为恢复, 之后二者差异不明显; 福建省长汀县和闽清县在整个植被自然恢复过程中土壤有机质和全氮累计增量和年平均增量都比陕北地区高。因此, 建议福建省长汀县和闽清县应先进行人为植被恢复, 然后进行自然恢复; 而陕北地区应先进行自然恢复,再人为恢复和自然恢复相结合, 这样可有效改善土壤有机质和全氮含量, 加快植被恢复。

Change characteristics and regional differences in organic matter and total nitrogen contents in topsoil under restored vegetation

There exist significant differences in the impacts of vegetation restoration on soil chemical properties in different regions. In this paper, the previous data on organic matter and total N in the 0~20 cm topsoil in typical revegetated areas of Changting and Minqing Counties of Fujian Province, and Shaanbei region of Shaanxi Province were analyzed. The change characteristics of soil organic matter and total N under natural vegetation recovery were compared with those under artificial vegetation restoration. The results showed that compared with natural recovery in Changting and Minqing Counties of Fujian Province, the influence of artificial restoration on soil organic matter and total N was greater at the initial period, but was contrary at the later period. At the initial period of restoration in Shaanbei region, natural recovery gave more favorable effects on soil organic matter and total N contents than artificial restoration. However, the differences between natural recovery and artificial rehabilitation became less apparent in the latter periods of restoration. Cumulative and annual average increments in organic matter and total N under natural recovery were greater in Changting and Minqing Counties than in Shaanbei region. It was therefore recommended that artificial restoration be first implemented, followed by natural recovery in Changting and Minqing Counties of Fujian Province. In Shaanbei region, natural recovery should first be implemented, followed by integrated artificial and natural restoration. The above techniques could effectively improve soil organic matter and total N contents, which would in turn accelerate vegetation restoration in both provinces.