Changes in Active Organic Carbon of Erosion Red Soil by Vegetation Recovery

The erosion red soil distributed in subtropical area of China has poor soil fertility. Vegetations recovery in erosion red soil will improve soil quality, to inspect the effects of different types of vegetation, samples from two trial sites with respective 9-year and 17-year history of vegetation recovery were collected. It was found that each fraction of soil organic carbons invested this study such as: soil total organic C(TOC), microbial organic C (MBC), water-soluble organic C (WSOC) and microbial respiration C (MRC) increased with the growing of vegetation, TOC,MBC,WSOC and MRC in soil under Chinese fir stand with 17-year recovery history were respective 2.18, 2.95,2.25 and 2.01 times as those with 9-year recovery history. It was observed that different types of vegetation caused dissimilarity changes in C fractions. Each fraction of C in soil under Schima superba was generally more abundant than that under Chinese fir. Soil under rye contained much more MRC compared with Chinese fir and Citrus changshan-huyo, and so did proportion of MRC over TOC indicating a strong potential of mineralization in this soil. The proportion of MBC and WSOC of soil in Chinese fir stand increased from 9- year to 17-year, but declined in MRC/TOC. Soil TOC,MBC,WSOC and MRC were interrelated closely(p0.01), and they also well correlated (p0.01)with soil total N, hydrolysable N, and available P.