title: Variation of Soil Organic Carbon and Its Major Constraints in East Central Asia.
abstract: Variation of soil organic carbon (SOC) and its major constraints in large spatial scale are critical for estimating global SOC inventory and projecting its future at environmental changes. By analyzing SOC and its environment at 210 sites in uncultivated land along a 3020km latitudinal transect in East Central Asia, we examined the effect of environmental factors on the dynamics of SOC. We found that SOC changes dramatically with the difference as high as 5 times in north China and 17 times in Mongolia. Regardless, C:N remains consistent about 12. Path analysis indicated that temperature is the dominant factor in the variation of SOC with a direct effect much higher than the indirect one, the former breaks SOC down the year round while the latter results in its growth mainly via precipitation in the winter half year. Precipitation helps accumulate SOC, a large part of the effect, however, is taken via temperature. NH4+-N and topography also affect SOC, their roles are played primarily via climatic factors. pH correlates significantly with SOC, the effect, however, is taken only in the winter months, contributing to the decay of SOC primarily via temperature. These factors explained as much as 79% of SOC variations, especially in the summer months, representing the major constraints on the SOC stock. Soil texture gets increasingly fine southward, it does not, however, constitute an apparent factor. Our results suggested that recent global warming should have been adversely affecting SOC stock in the mid-latitude as temperature dominates other factors as the constraint.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Xinqing
authors.initials: X
authors.lastname: Lee
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Daikuan
authors.initials: D
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Hu
authors.affiliation: Key Laboratory of West China's Environmental System (Ministry of Education), Lanzhou University, 298 Tianshui Road, Lanzhou, 730000, Gansu, China.
authors.forename: Zhaodong
authors.initials: Z
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guiyang, 550081, Guizhou, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ni
authors.affiliation: Nuclear Research Center, National University of Mongolia, 14200, Ulaanbaatar, Mongolia.
authors.forename: Tserenpil
authors.initials: T
authors.lastname: Shurkhuu
mesh_terms: D002244:Carbon / Q000737:chemistry*; D017753:Ecosystem; D004784:Environmental Monitoring; D005202:Asia, Eastern; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000737:chemistry*; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen