第2代杉木林土壤有机碳、全氮对细根分布及形态特征的影响

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

以20年生杉木人工林为研究对象，分析了杉木细根的生长分布情况及形态学特征．结果表明：第2代杉木人工林的土壤有机碳与全氮主要分布在0～30cm土壤中，随着土壤深度的增加而明显减少；杉木细根生物量在不同土壤层次间差异显著，随土壤深度的增加而显著减少，主要分布在0～15cm的表层土壤中，占总量的50．35％，15～30cm层占30．04％，30～45cm层占19．61％；细根表面积在不同层次土壤间差异不显著，主要分布在0～30cm层中，为2．86m2·m^-3，占总量的79．88％；随着土壤深度的增加，杉木细根比根长增加不明显；土壤有机碳含量与杉木细根生物量、比根长和根表面积密度之间相关性均不显著；土壤全氮含量与杉木细根生物量和根表面积密度之间存在明显的正相关，与细根比根长存在不太明显的负相关．

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 0～30cm 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 15～30cm layer and 19. 61% in the 30～45 cm layer that the fine-root surface area is also distributed in the 0～30cm 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.