洛川黄土/古土壤中有机碳的分布特征及其与粘土矿物的相关性

系统测定了陕西洛川黑木沟黄土/古土壤的总有机碳及其主要组分(稳定有机碳、矿物保护有机碳和化学稳定有机碳)的含量,并对总有机碳与粘粒含量及粘土矿物含量的相关性进行了分析。结果表明:(1)各层古土壤的总有机碳含量均高于其下伏的黄土层(S4例外),而稳定有机碳、矿物保护有机碳以及化学稳定有机碳的平均含量在黄土与古土壤之间无明显差异;(2)黄土和古土壤中有机碳含量达到稳定所需要的时间不同,分别是140~250 ka和330~410ka;(3)总有机碳和化学稳定有机碳与粘粒呈正相关关系(相关系数r分别为0.46和0.54),它们与粉粒和细砂粒的相关性较差,这说明粘粒是土壤固定有机碳的重要组分;(4)高岭石与总有机碳和化学稳定有机碳的相关性比较明显(r分别为0.74和0.61),伊利石和蒙脱石与它们不相关或相关性较差。

Distribution of organic carbon in the Luochuan loess/paleosol and its relationship with clay minerals

The total organic carbon(TOC) and its major components,i.e.,stable organic carbon(StOC),mineral-protected organic carbon(MOC),and chemical resistant organic carbon(COC),were analyzed for both loess and paleosol layers in Luochuan profile,and the correlations between the clay particle content,clay mineral content and TOC content were studied.The results are as follows:(1) the content of TOC is higher in paleosol(except for S4) than in loess,but the differences of the average content of StOC,MOC,COC are not o...