Pedosphere 15(5): 676--680, 2005
ISSN 1002-0160/CN 32-1315/P
©2005 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Soil organic carbon and labile carbon along a precipitation gradient and their responses to some environmental changes |
WANG Shu-Ping1,2, ZHOU Guang-Sheng1 , GAO Su-Hua3 and GUO Jian-Ping3 |
1 Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093 (China). E-mail: zhougs@public2.bta.net.cn;
2 College of Resources and Environment, Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China);
3 Chinese Academy of Meteorological Science, Beijing 100081 (China) |
| ABSTRACT |
| Based on data from a field survey in 2001 along the Northeast China transect (NECT), a precipitation gradient, and a short-term simulation experiment under ambient CO2 of 350 μmol mol-1 and doubled CO2 of 700 μmol mol-1 with different soil moisture contents of 30%-45%, 45%-60%, and 60%-80% soil water holding capacity, the distribution of soil organic carbon and labile carbon along the NECT, their relationships with precipitation and their responses to CO2 enrichment and soil moisture changes were analyzed. The results indicated that the soil labile carbon along the gradient was significantly related to soil organic carbon (r = 0.993, P < 0.001). The soil labile carbon decreased more rapidly with depth than organic carbon. The soil organic and labile carbon along the gradient decreased with decrease in longitude in both the topsoils and subsoils, and the coel&cient of variation for the labile carbon was greater than that for the organic carbon. Both the soil organic carbon and labile carbon had significant linear relationships with precipitation, with the correlation coel&cient of soil organic carbon being lower (0.677 at P < 0.001) than that of soil labile carbon (0.712 at P < 0.001). In the simulation experiment with doubled and ambient CO2 and different moisture contents, the coel&cient of variation for soil organic carbon was only 1.3%, while for soil labile carbon it was 29.7%. With doubled CO2 concentration (700μmol mol-1), soil labile carbon decreased significantly at 45% to 60% of soil moisture content. These indicated that soil labile carbon was relatively more sensitive to environmental changes than soil organic carbon. |
| Key Words: environmental changes, labile carbon, organic carbon, precipitation gradient, soil |
| Citation: Wang, S. P., Zhou, G. S., Gao, S. H. and Guo, J. P. 2005. Soil organic carbon and labile carbon along a precipitation gradient and their responses to some environmental changes. Pedosphere. 15(5): 676-680. |
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