长白山森林土壤有机碳库大小及周转研究

Determination of Forest Soil Organic Carbon Pool Sizes and Turnover Rates in Changbaishan

主要分析不同森林植被下有机碳的分解动态和土壤碳库各组分大小、周转时间。结果表明：土壤样品培养90天，CO2累计释放量表层大致为1723～5065mg／kg、下层大致为178～642mg／kg。分解速率总的趋势是前期快，后期慢，表层明显大于下层。大小顺序为：冷杉林〉针阔混交林和阔叶林〉针叶林。在不同植被下的表层和下层土壤中，活性碳占总有机碳的0．54％～1．67％，0．45％～5．48％．平均驻留时间为11～56天、60～88天；缓效性碳占总有机碳的23．0％～63．3％，33．2％～72．2％，平均驻留时间为4～70年、24～161年；惰效性碳占总有机碳的35．5％～75．5％．26．0％～65．%。表层土壤的总有机碳、活性碳、缓效性碳和惰效性碳含量都明显大于下层。凋落物的化学组成主要决定活性碳库、缓效性碳库含量，土壤的粘粒含量等性质主要决定惰效性碳库含量。

The dynamics of soil organic carbon （SOC）decompositions and the carbon pool sizes and turnover rates of active carbon pool,slow carbon pool and resistsant carbon pool under different vegetations are discussed in the paper. The results indicate that cumulative emission of CO2 is 1 723-5 065 mg/kg in the surface soil and 178- 642 mg/kg in the subsoil from incubation data for 90 days. The general trend is that the former decomposition rate is faster than later period and in the surface soil than in the subsoil. Decomposition rate decrease in the order of silver fir, birch and mixed forest, pine forest. Under different vegetations, the size of active carbon pool from surface and subsoil respectively accounts to 0. 54-1.67% and 0.45-5.48% of total soil organic carbon, and the mean residue time is 11-56 days and 60-88 days; Slow carbon pool, 23.0%-63.3% and 33.2%-72.2%, 4 -70 years and 24-161 years; Resistant carbon pool, 35.5%-75.5% and 26.0-65.0% ;The contents of soil organic carbon,active carbon,slow carbon and resistant carbon is more in the surface soil than subsoil. The chemical composition of litter from vegetation mainly determine the content of active carbon pool and slow pool. The resistant carbon pool is mainly determined by soil clay and other physical and chemical character.