Soil Organic Carbon and Its Fractions Across Vegetation Types:Effects of Soil Mineral Surface Area and Microaggregates  

作　　者：WU Qing-Biao WANG Xiao-Ke OUYANG Zhi-Yun 

机构地区：[1]Forestry College of Guangxi University, Nanning 530004 China [2]Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 China

出　　处：《Pedosphere》2009年第2期258-264,共7页土壤圈（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Nos.40321101 and 40071036);the Major State Basic Research Development Program of China(973 Program)(No.2002CB412503)

摘　　要：Soil organic carbon(SOC)can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and the underlying mechanisms that stabilize SOC.In this study,density fractionation and acid hydrolysis were used to assess the spatial variation in SOC,the heavy fraction of organic carbon(HFOC),and the resistant organic carbon(ROC)in soils of the southern Hulun Buir region,northeastern China,and to identify the major factors that contribute to this variation.The results showed that as the contents of clay and silt particles(0–50μm)increased,both methylene blue(MB)adsorption by soil minerals and microaggregate contents increased in the 0–20 and 20–40 cm soil layers(P<0.05).Although varying with vegetation types,SOC,HFOC,and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals,and microaggregate content(P<0.05),suggesting that soil texture,the MB adsorption by soil minerals,and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.Soil organic carbon （SOC） can act as a sink or source of atmospheric carbon dioxide; therefore, it is important to understand the amount and composition of SOC in terrestrial ecosystems, the spatial variation in SOC, and the underlying mechanisms that stabilize SOC. In this study, density fractionation and acid hydrolysis were used to assess the spatial variation in SOC, the heavy fraction of organic carbon （HFOC）, and the resistant organic carbon （ROC） in soils of the southern Hulun Buir region, northeastern China, and to identify the major factors that contribute to this variation. The results showed that as the contents of clay and silt particles （0-50μm） increased, both methylene blue （MB） adsorption by soil minerals and microaggregate contents increased in the 0 20 and 20 40 cm soil layers （P 〈 0.05）. Although varying with vegetation types, SOC, HFOC, and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals, and microaggregate content （P 〈 0.05）, suggesting that soil texture, the MB adsorption by soil minerals, and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.

关 键 词：carbon fractions MICROAGGREGATES soil mineral surface area soil organic carbon VEGETATION 

分 类 号：S153.621[农业科学—土壤学] S153.61[农业科学—农业基础科学]