Effects of Soil Nutrients on Fine-root Biomass,Root Surface-area and Specific Root Length of Chinese fir Plantation in Huitong,Hunan Province

Taking a 20-year-old second-rotation Chinese fir plantation as research object,the paper analyzed the growing distribution and morphological characteristics of its fine roots.Results show that the contents of soil organic carbon and nitrogen are mainly distributed in the soil of a 0～30 cm depth and decrease significantly with the increase of soil depth;that the fine-root biomass shows a significant difference among different layers of soil,decreasing with the increase of soil depth,and it accounts for 50.35% of the total in the 0～15 cm layer, 30.04% in the 15～30 cm layer and 19.61% in the 30～45 cm layer;that the fine-root surface area is also distributed in the 0～30 cm layer,accounting for 79.88% of the total;that the distribution of specific root length in different soil layers is considerably even and shows a slight increasing trend with the increase of soil depth;that the content of soil organic carbon bears no obvious correlation to the fine-root biomass,the specific root length and the root-surface area but the total nitrogen content does an obviously positive correlation to the fine-root biomass and the root surface-area density except the specific root length to which it has a faintly negative correlation.