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Pedosphere 22(4): 489--496, 2012
ISSN 1002-0160/CN 32-1315/P
©2012 Soil Science Society of China
Published by Elsevier B.V. and Science Press

Dynamics of soil organic carbon under uncertain climate change and elevated atmospheric CO₂

LIN Zhong-Bing and ZHANG Ren-Duo

Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

ABSTRACT

Climate change and elevated atmospheric CO₂ should affect the dynamics of soil organic carbon (SOC). SOC dynamics under uncertain patterns of climate warming and elevated atmospheric CO₂ as well as with different soil erosion extents at Nelson Farm during 1998-2100 were simulated using stochastic modelling. Results based on numerous simulations showed that SOC decreased with elevated atmospheric temperature but increased with atmospheric CO₂ concentration. Therefore, there was a counteract effect on SOC dynamics between climate warming and elevated CO₂. For different soil erosion extents, warming 1 ℃ and elevated atmospheric CO₂ resulted in SOC increase at least 15%, while warming 5 ℃ and elevated CO₂ resulted in SOC decrease more than 29%. SOC predictions with uncertainty assessment were conducted for different scenarios of soil erosion, climate change, and elevated CO₂. Statistically, SOC decreased linearly with the probability. SOC also decreased with time and the degree of soil erosion. For example, in 2100 with a probability of 50%, SOC was 1617, 1167, and 892 g m^-2, respectively, for no, minimum, and maximum soil erosion. Under climate warming 5 ℃ and elevated CO₂, the soil carbon pools became a carbon source to the atmosphere (P > 95%). The results suggested that stochastic modelling could be a useful tool to predict future SOC dynamics under uncertain climate change and elevated CO₂.

Key Words: atmospheric carbon dioxide, climate warming, soil carbon pools, soil erosion, stochastic modelling

Citation: Lin, Z. B. and Zhang, R. D. 2012. Dynamics of soil organic carbon under uncertain climate change and elevated atmospheric CO₂. Pedosphere. 22(4): 489-496.

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