【摘要】 选择了采自江苏省吴县市的黄泥土、乌泥土、白土等太湖地区代表性水稻土 ,测定了土壤有机碳的剖面分布、易氧化性碳分异、在土壤团聚体中的分布及 13 C稳定性同位素的剖面分异 .结果表明太湖地区水稻土中有机碳储量达 7～ 10 kg/m2 ,有机碳主要分布于 2～ 0 .2 5mm和 0 .2 5～0 .0 2 mm两级团聚体中 ,各土壤间有机碳的氧化活泼性接近 ,稳定性同位素组成类似 ,说明其有机碳地球化学性质趋向于与当前 C- 3农作物利用状况相平衡 .更多还原

【Abstract】 Selected 3 types of the paddy soils in Taihu Lake region were sampled.The profile distribution of soil orgamic carbon(SOC) was studied by precision depth sampling technique.Soil aggregates of different size were separated by ultrasonic dispersion followed by sieving,sedimentation and centrifuge,and then their carbon contents were determined respectively.The C lability was analyzed by KMnO 4 oxidation procedure.The stable carbon isotope composition was determined by mass spectrum.The carbon storage of the soils was shown to be 7～10kg C/m 2.The organic carbon was mainly found in the aggregates in size of 2~0.25mm and 0.25~ 0.02 mm.There was hardly difference in carbon lability between the soil types and between the profile layers.The almost constant composition of 13 C in profile depths indicated similar origin of the SOC by the present cropping system predominated by rice and wheat rotations.更多还原