EGU21-1902, updated on 03 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spatial heterogeneity of subsoil organic carbon turnover times in forest ecosystems across China

Peng Yu1, Xiaolu Tang2,3, Yuehong Shi1, Chunju Cai4, Yuxuan Han5, Zhou Li5, Luo Deng5, Ci Song5, and Jingji Li2,3
Peng Yu et al.
  • 1College of Earth Science, Chengdu University of Technology, Chengdu , China (
  • 2College of Ecology and Environment, Chengdu University of Technology, Chengdu , China (;
  • 3State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & Water Pollution, Chengdu University of Technology, Chengdu , China (;
  • 4Key Laboratory of Bamboo and Rattan Science and Technology of National Forestry and Grassland Administration, International Centre for Bamboo and Rattan, Beijing , China
  • 5China Railway Eryuan Engineering Group Co. Ltd., Chengdu, China

Soil organic carbon turnover time (τ, year) is an important indicator of soil carbon stability and sequestration capacity. However, our understanding of the spatial heterogeneity of subsoil τ still was poorly qualified over a large scale, even though subsoil organic carbon below 0.2 m accounts for the majority of total soil organic carbon. We compiled a dataset that consisted of 630 observations in subsoil (0.2 - 1 m) from published literatures to investigate the spatial heterogeneity of subsoil τ (defined as the ratio of soil carbon stock and net primary production) and explore its main environmental drivers using structural equation modelling (SEM) in forest ecosystems across China. Results indicated that mean (± standard deviation) subsoil τ was 72.4 ± 68.6 years with a large variability ranging from 2.3 to 896.2 years. Subsoil τ varied significantly with forest types that mean subsoil τ was the longest in deciduous broadleaf forest (82.9 ± 68.7 years), followed by evergreen needleleaf forest (77.6 ± 60.8 years), deciduous needleleaf forest (75.3 ± 78.6 years) and needleleaf and broadleaf mixed forest (71.3 ± 80.9 years), while the shortest τ in evergreen broadleaf forest (59.9 ± 40.7 years). SEM suggested that soil environment was the most important factor in predicting subsoil τ. However, the dominant driver differed with forest types, i.e. soil environment for evergreen broadleaf forest and climate for evergreen needleleaf forest. This study highlights the different dominant controlling factors in subsoil τ and improve our understanding of biogeographic variations of subsoil τ. These findings are essential to better understand (and reduce uncertainty) in biogeochemical models of subsoil carbon dynamics at regional scales.

How to cite: Yu, P., Tang, X., Shi, Y., Cai, C., Han, Y., Li, Z., Deng, L., Song, C., and Li, J.: Spatial heterogeneity of subsoil organic carbon turnover times in forest ecosystems across China, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1902,, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.