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.