不同森林植被下土壤有机碳的分解特征及碳库研究

分析了不同森林植被和同一植被不同林龄的人工杉木林下土壤有机碳的分解特征及土壤有机碳中的活性碳库、缓效性碳库和惰效性碳库的大小和周转时间。结果表明:不同森林植被下土壤有机碳的分解速率不同,总的趋势都是:培养前期分解速度快,后期分解速度慢,土壤剖面A层>剖面B层。在剖面A层中:不同森林植被下分解速率的大小顺序为常绿阔叶林>人工杉木林,不同林龄的人工杉木林为成熟林>中龄林>幼龄林;在剖面B层中:分解速率差异不大。不同森林植被下不同土壤剖面上的土壤活性碳库、缓效性碳库和惰效性碳库的库容和分解速率不同,土壤活性碳库碳含量一般占总有机碳的0 99%～2 89%,田间平均驻留时间为10～23天;土壤缓效性碳一般占总有机碳的17 17%～55 46%,田间平均驻留时间为1 6～24 2年;土壤惰效性碳一般占总有机碳的42 05%～80 66%,田间平均驻留时间为假定的1000年。

Study on Characteristics of Soil Organic Carbon Decompositions and Carbon Pool under Different Vegetations

The characteristics of soil organic carbon (SOC)decompositions and the carbon pool sizes and turnover rates of active carbon pool,slow carbon pool and passive carbon pool under different vegetations and Chinese fir plantation of different forest ages are discussed. The results indicate that the general trend is there is a faster decomposition rate in the first incubation period than in the second period and in the surface soil than in the subsoil.In the surface soil,effect of decomposition rate on different vegetations is broad leaved forest>mature Chinese fir plantation and on Chinese fir plantation of different forest ages is midaged forest>mature forest>young forest.In the subsoil,there is a few differences on decomposition rate and culmulative amount of carbon mineralized under different vegetations;Effect of culmulative amount of soil organic carbon mineralized on different vegetations and Chinese fir plantation of different forest ages is the first month>the second month>the third month, the surface soil>the subsoil.In the surface soil,the effect is midaged Chinese fir plantation > broad leaved forest >mature Chinese fir plantation >young Chinese fir plantation;There is a different carbon pool sizes and turnover rate of activecarbon pool, slow carbon pool and passive carbon pool under different vegetations and Chinese fir plantation of different forest ages,the active pool(Ca)comprised 1.70% to 4.98% of the SOC in the surface and subsoil with an average field mean residence time(MRT) of 10 to 23 d,the slow pool comprised 16.21% to 49.52% of the SOC ,they had field MRT of 0.8 to 13.1 year,the passive pool comprised 46.22% to 80.50% with a assumed field MRT of 1 000 year.