马尾松林地与玉米地土壤有机碳的分异研究  

Variance of soil organic carbon between masson pine soil profile and corn soil profile

作　　者：涂成龙[1,2] 刘丛强[1] 武永锋[1,2] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002 [2]中国科学院研究生院,北京100039

出　　处：《生态环境》2008年第1期261-267,共7页Ecology and Environmnet

基　　金：国家重点基础研究发展规划(973)项目(2006CB403200)

摘　　要：林农生态系统转化对土壤有机碳(SOC)组成和来源产生了较大的影响,但不同学者的结论仍然存在一定差异,且这一转化过程对土壤溶解性有机碳(DOC)的影响鲜有报道。基于这一背景,该研究在贵州中部区域选择马尾松(Pinus massoniana)林地和玉米(Zea mays L.)地土壤作为研究对象,通过对SOC和DOC含量和同位素组成的测定,分析林农生态系统转化前后土壤有机碳的分异。结果表明,在马尾松林地剖面中,SOC和DOC含量随剖面深度的变化幅度均大于玉米地土壤,DOC含量最大值出现在5～10cm处;δSO13C和δDO13C随着土壤深度的加深有所偏正,但δDO13C在剖面中的变异远大于δSO13C,其极差分别为5.015‰和2.431‰;通过对比δDO13C和δSO13C的差异,说明其0～5cm的DOC主要来源于新成枯枝落叶,而土体内部DOC则主要来自土壤腐殖类物质的转化。在玉米地剖面中,δSO13C和δDO13C随着土壤深度的加深有所偏负,但整个剖面中两值的差异较小,DOC主要来源于土壤腐殖类物质的转化;SOC来源于玉米植物体有机碳(C4-C)的比例介于2.55%～20.80%之间,随剖面层次的加深有降低趋势,但出现"之"字形反复;DOC中C4-C的比例在剖面0～40cm间较为相近(25.94%～34.54%),40cm以下则急剧下降(3.18%～15.65%)。The origin and component of soil organic carbon （SOC） change with shift of forest-crop ecosystem, but the results aren＇t identical and there are few reports about soil dissolved organic carbon （DOC） during this process. Based on this background, two soil profiles under Masson pine and corn were selected to characterize the difference of the process of turnover ecosystem. The content and 513C of SOC and DOC were determined to analyze the influence of turnover ecosystem on soil organic matter. The results show that in the Masson pine soil profile the various range of SOC is bigger than that in corn soil profile, but the max values of DOC are not in the surface soil; the δSO^13Cand δSO^13C become more positive with soil depth, the range are 5.015‰ and 2.431‰ respectively. By analyzing the difference of δSO^13C and δSO^13C in the Masson pine Soil profile, it indicates that DOC in 0 - 5cm mainly derive from litter, while that under 5cm derives from degradation of humus. In corn soil profile, the δSO^13C and δSO^13C become more negative with soil depth, but the difference of the two values is small. The C4-C percentage of SOC is between 2.55% and 20.80%, but zigzag with soil depth. The C4-C percentage of DOC in 0 - 40 cm is similar （25.94% - 34.54%）, while that under the 40cm decreases abruptly （3.18% - 15.65%）.

关 键 词：生态系统转化 Δ^13C 有机碳 溶解性有机碳 含量 来源 

分 类 号：X144[环境科学与工程—环境科学]