不同土地利用类型下土壤活性有机碳库的变化

分析了中国科学院沈阳生态试验站不同土地利用类型长期定位试验土壤0～40cm活性有机碳含量,结果表明:0～20cm土层内荒地土壤有机碳、易氧化碳、微生物生物量碳、溶解性有机碳和轻组有机碳含量高于割草地和裸地,而割草地颗粒有机碳含量略高于荒地;在20～40cm土层,割草地土壤有机碳、易氧化碳和颗粒有机碳含量较高,而荒地微生物量碳、溶解性有机碳和轻组有机碳含量较高。不同土地利用类型土壤活性有机碳含量均随着土层加深而递减。土壤微生物量碳、溶解性有机碳和轻组有机碳的分配比例为荒地>割草地>裸地,易氧化碳和颗粒有机碳的分配比例为割草地>荒地>裸地。土壤活性有机碳的分配比例随土层加深而下降,但溶解性有机碳的分配比例变化趋势相反。

Changes of soil active organic carbon pool under different land use types

The measurement of active organic carbon content in 0-40 cm soil layer under different land use types in Shenyang Eco-experiment Station of Chinese Academy of Sciences showed that in 0-20 cm soil layer,the contents of organic carbon(OC),readily oxidizable carbon(ROC),microbial biomass carbon(MBC),dissolved organic carbon(DOC) and light fraction organic carbon(LFOC) were higher in fallow field than in mowing field and bare field,while the content of particulate organic carbon(POC) was relatively higher in mowing field than in fallow field.In 20-40 cm soil layer,the contents of OC,ROC and POC were higher in mowing field,while those of MBC,DOC and LFOC were higher in fallow field.The profile distribution of soil active organic carbon under different land use types appeared a declining trend with soil depth.The allocation proportion of MBC,DOC and LFOC in soil active organic carbon followed the order of fallow field> mowing field> bare field,while that of ROC and POC was in the order of mowing field> fallow field> bare field.The allocation proportion of soil active organic carbon had a declining trend with depth,while that of DOC was in adverse.