苏南丘陵地区栓皮栎次生林与火炬松人工林土壤有效碳

Soil labile carbon in secondary Quercus variabilis forest and Pinus taeda plantation in hilly area of South Jiangsu,China

采用重复熏蒸-培养法研究了苏南丘陵地区具有代表性的栓皮栎次生林和火炬松人工林土壤有效碳的变化特征。结果表明:栓皮栎次生林土壤中的有效碳和微生物量碳含量均显著高于火炬松人工林,而火炬松人工林土壤有效碳占总有机碳比率(4.7%)及土壤微生物量碳含量占土壤有效碳比率(54.3%)分别高于栓皮栎次生林(2.9%和40.9%);去除森林凋落物后,2种林分土壤有效碳含量均显著降低;土壤有效碳与土壤微生物量碳以及土壤总有效碳显著相关。重复熏蒸-培养法是估测该地区森林土壤有效碳的一种简单有效的方法。与火炬松人工林相比,天然次生栓皮栎林土壤含有较多的活性有机碳,可能对区域碳平衡产生较大的影响。

By using sequential fumigation-incubation method, the soil laDUe carbon in a secondary Quercus variabilis forest and a Pinus taeda plantation in hilly area of South jiangsu, China was investigated. The results showed that soil labile carbon and microbial biomass carbon were significantly higher in secondary Q. variabilis forest than in P. taeda plantation, while the ratio of soil labile carbon to soil total organic carbon and that of soil microbial biomass carbon to soil labile carbon were higher in P. taeda plantation than in secondary Q. variabilis forest （4. 7% and 54.3% vs. 2.9% and 40.9% , respectively）. The soil labile carbon in the two forests reduced significantly after litter removal. Soil labile carbon had significant correlations with soil microbial biomass carbon and total organic carbon. It was found that sequential fumigation-incubation was an effective and easy method to measure and estimate the labile carbon in forest soils in this area. Compared with P. taeda plantation, secondary Q. variabilis forest had more soil labile carbon, which might have greater influence on the local carbon cycle.