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| Effects of Eisenia fetida Inoculation on Soil Organic Carbon and Soil Microorganisms Under Rice Straw Application |
| Received:July 12, 2014 |
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| KeyWord:earthworm;residue addition;soil organic carbon;soil sterilization;soil microorganism |
| Author Name | Affiliation | E-mail | | YAO Ying | College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China | | | HE Jing | College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China | | | ZHANG Yi | College of Resources and Environment Sciences, China Agricultural University, Beijing 100193, China | | | LI Yu-fei | Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China | | | WU Yu-peng | College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China | wyp19851205@126.com |
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| Abstract: |
| Earthworms influence soil organic carbon dynamics directly through their biological activities and indirectly via modified indigenous soil organisms. In this microcosm study, un-sterilized and sterilized soils(indigenous organism's free soil) were used to compare the differences in soil organic carbon and microorganisms induced by earthworm(Eisenia fetida) over the 30-day study period. Soils inoculated with earthworms increased cumulative CO2 emissions and microbial biomass carbon compared with no earthworm soil, while significant differences were observed only in the sterilized soil. The effects of earthworms on soil total organic carbon, labile organic carbon and dissolved organic carbon varied depending on sterilization. The presence of earthworm decreased soil labile organic carbon from 5.39 g·kg-1 to 5.06 g·kg-1 in un-sterilized soil, while significantly increased from 5.62 g·kg-1 to 6.45 g·kg-1 in sterilized soil. Meanwhile, terminal restriction fragments(TRFs) were more diverse in sterilized soil with earthworms than one without earthworm, while no obvious changes were found in un-sterilized soils, in which the presence and absence of earthworms shared almost 50% of TRFs. Redundancy analysis showed that there were no obvious clustering phenomena among all treatments, indicating the changes in bacterial community structure by earthworm inoculation. Nevertheless, earthworm inoculation in sterilized soil was correlated positively with cumulative CO2 emissions, microbial biomass carbon, labile organic carbon and dissolved organic carbon. In conclusion, earthworms may change soil organic carbon by stimulating and changing soil bacterial community by gut-associated bacteria in the sterilized soil, which may be diminished due to the competition of indigenous soil microorganisms in un-sterilized soil. |
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