Comparison of Soil Liable Organic Carbon in Secondary Forests and Chinese Fir Plantations

To assess the effects of land use type conversion on soil liable organic carbon pool, in this paper we collected soil samples in natural secondary forests and Chinese fir plantations that reached mature forest state in Miaoshanwu Forest Ecosystem Research Station of Fuyang city, Zhejiang province. We compared soil liable organic carbon in the depth of 060 cm by means of fixed plots investigation method and laboratory analysis method. The content of TOC, WSOC, EOC and LFOM showed a downward trend with the conversion of natural secondary forests to Chinese fir plantations, and the variations in amplitude were 12.1%-44.9%, 2.7%-11.7%, 1.2%-16.5% and 17.8%-39.8%, respectively. There were significant differences between WSOC and TOC content in the depth of 010 cm. The available ratios of EOC and WSOC of Chinese fir plantations were significantly higher than those of natural secondary forests in the depth of 0-10cm. Soil labile organic carbon and soil nutrients were significantly related to TOC, except that the relationship between WSOC and available P was not significant. The correlation coefficient between soil liable organic carbon and total N was the highest, while the lowest correlation coefficient existed between soil liable organic carbon and available P.