小兴安岭两种林型的土壤有机碳研究

Study on Soil Organic Carbon under Two Types of Vegetation in Small Xing′an Mountains

为阐明小兴安岭两种原始红松林土壤有机碳变化特征及其影响机制,采样分析了云冷杉红松林与椴树红松林土壤总有机碳、易氧化碳、微生物生物量碳及土壤理化性质。结果表明:两种林型土壤总有机碳、易氧化碳、微生物生物量碳含量垂直分布特征一致,均自上向下逐渐减少;土壤总有机碳与易氧化碳含量表现为:云冷杉红松林<椴树红松林,同海拔高度变化(云冷杉红松林<椴树红松林)一致(仅10—20cm土层,云冷杉红松林的两个因子高于椴树红松林,但差异不显著),两种林型土壤微生物量碳含量的差异在不同土壤层次有所不同,但差异均不显著;两种林型间土壤活性碳占总有机碳比率的差异在不同土层无一致的规律性;两种活性碳、总有机碳与土壤全氮、C/N之间为显著(p<0.05)或极显著(p<0.01)正相关,与土壤容重呈极显著负相关(p<0.01)。

To understand the characteristics of soil organic carbon and its correlations with soil properties in the two original Korean pine forests in Small Xing′an Mountains,Korean Pine and spruce-fix mixed forests,Tilia amurensis—Pinus karaiensis mixed forests were selected in this study,and soil samples were analyzed for soil total organic carbon(TOC),easily-oxidized carbon(EOC),microbial biomass carbon(MBC)and basic properties.Results showed that there was the same character in vertical distribution that the contents of soil TOC,EOC and MBC in the two forest types all decreased with soil depth.Exception of the depth of 10—20cm,the contents of soil TOC and EOC ranged in order as follow:Korean Pine and sprucefix mixed forests<Tilia amurensis-Pinus karaiensis mixed forests,it had the same trend as elevation gradient(Korean Pine and spruce-fix mixed forests<Tilia amurensis—Pinus karaiensis mixed forests).Levels of soil MBC varied in different soil depths for the two forest types.The EOC/TOC,MBC/TOC ratios varied.Soil EOC,MBC and TOC were all significantly related to total N and C/N,and were significantly negatively related to soil bulk density.