A conceptual model of the controlling factors of soil organic carbon and nitrogen densities in a permafrost‐affected region on the eastern Qinghai‐Tibetan Plateau.

• Main Authors: Wu, Xiaodong, Hongbing, Fang, Zhao, Yonghua, Smoak, Joseph M., Li, Wangping, Shi, Wei, Sheng, Yu, Zhao, Lin, Ding, Yongjian
• Format: Text
• Language: unknown
• Published: Digital Archive 2017
• Subjects: Soil; Organic Carbon; Nitrogen; Permafrost; Qinghai-Tibetan Plateau; Active layer thickness; permafrost
• Online Access: https://digital.stpetersburg.usf.edu/fac_publications/2894; https://login.ezproxy.lib.usf.edu/login?url=http://onlinelibrary.wiley.com/doi/10.1002/2016JG003641/epdf

Many investigations of the preservation of soil organic carbon (SOC) in permafrost regions have examined roles of geomorphology, pedogenesis, vegetation cover and permafrost within particular regions. However, it is difficult to disentangle the effects of multiple factors on the SOC in permafrost regions due to the heterogeneity in environmental conditions. Based on data from 73 soil study sites in permafrost regions of the eastern Qinghai-Tibetan plateau, we developed a simple conceptual model, which relates SOC to topography, vegetation and pedogenesis. We summarized the dominant factors and their controls on SOC using 31 measured soil physiochemical variables. Soil texture explains approximately 60% of the variations in the SOC stocks for the upper 0-2 m soil. Soil particle size closely correlates to soil moisture, which is an important determinant of SOC. Soil salinity and cations are important factors as well, and can explain about 10% of the variations in SOC. The SOC and TN stocks for the 1-2 m depths have larger uncertainties than those of upper 1 m soil layer. The vegetation, pH and bulk density mainly affects SOC and TN stocks for the upper 1 m soil layers, while the active layer thickness and soil particle size have greater influence on SOC and TN stocks for the 1-2 m soils. Our results suggest that the soil particle size is the most important controller of SOC pools, and the stocks of SOC and TN are strongly effected by soil development processes in the permafrost regions of the eastern Qinghai-Tibetan Plateau.