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| Investigation of soil organic carbon mineralization and microbial community structure evolution of northeast paddy black soil in waterlogged and aerobic conditions |
| Received:January 03, 2017 |
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| KeyWord:soil organic carbon;mineralization characteristics;water condition;microbial activity;microbial community structure |
| Author Name | Affiliation | E-mail | | ZHANG Jing-zhi | College of Resources and Environment, Anhui Agriculture University, Hefei 230036, China | | | MA Chao | College of Resources and Environment, Anhui Agriculture University, Hefei 230036, China | | | GAO Hong-jian | College of Resources and Environment, Anhui Agriculture University, Hefei 230036, China | hjgao@ahau.edu.cn |
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| Abstract: |
| Soil carbon dynamics and microbial community structure were studied at 30 ℃ under simulated waterlogged and aerobic conditions in the laboratory. Results showed that soil total organic carbon(TOC) concentrations did not change during the 360-day incubation period in either waterlogged or aerobic conditions. The change in TOC concentrations was greater under waterlogged conditions(8.68%) than under aerobic conditions(6.23%), but the difference was not statistically significant(P>0.05). During the entire incubation period, the concentration of dissolved organic carbon(DOC) in waterlogged conditions was significantly greater than that under aerobic conditions(P<0.05). The mineralization rate constant(0.009 5 d-1) in waterlogged conditions was also significantly greater than that(0.007 5 d-1) in aerobic conditions; both rates were well fitted by the first-order kinetic equation. Values of the average well color development at 96 h(AWCD96 h) (an index of catabolism of specific carbon substrates) for microbial communities in waterlogged conditions were significantly lower than those in aerobic conditions from 0 to 15 d. There were no significant differences in AWCD from 30 to 60 d, but from 180 to 360 d, the AWCD values for anaerobic microbial communities were significantly greater(P<0.05) than those in aerobic conditions. At the beginning of incubation, the carbon resources used by soil microorganisms were mainly amino acids. In waterlogged conditions, they gradually changed to phenolic acids 30~60 d) and amino acids(180~360 d), while they changed to polymer carbon sources(60~360 d) in aerobic conditions. Waterlogged conditions increased the contents of soil DOC, soil microbial activity and metabolism, and the utilization of phenolic acid and amino acid carbon sources by soil microorganisms, and thus promoted the mineralization of soil organic carbon. |
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