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| Soil Pseudomonas spp., Bacillus spp., and microbial communities under tomato continuous cropping in greenhouse production |
| Received:October 14, 2015 |
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| KeyWord:greenhouse tomato;continuous cropping;microbial community structure;Bacillus spp.;Pseudomonas spp. |
| Author Name | Affiliation | E-mail | | GE Xiao-ying | Key Laboratory of Ecosystem Network Observation and Modeling/Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | SUN Zhi-gang | Key Laboratory of Ecosystem Network Observation and Modeling/Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China | | | LI Tao | Key Laboratory of Ecosystem Network Observation and Modeling/Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | OUYANG Zhu | Key Laboratory of Ecosystem Network Observation and Modeling/Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China | ouyz@igsnrr.ac.cn |
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| Abstract: |
| Long-term continuous cropping is unsustainable for vegetable production, especially for greenhouse vegetables. Most researchers have attributed the harmful effects of continuous cropping to the changes in soil microbial ecology. However, soil Pseudomonas spp. and Bacillus spp., two most important PGPR(plant growth promoting rhizobacteria) and dominant bacteria, have seldom been examined in investigating the microbial processes of continuous cropping obstacles until now. In this study, we investigated changes in soil Pseudomonas spp. and Bacillus spp. populations under continuous cropping and their relationships with soil microbial community using samples from 54 greenhouse tomato fields across continuous cropping years of 1~21 in Shouguang County and Yucheng County, Shandong, China. Results show that the number of total soil bacteria decreased as continuous cropping years increased, whereas the populations of Bacillus spp. and Pseudomonas spp. increased when continuous cropping years were shorter than 6~10 and then decreased after that. Results from PCR-DGGE(Denaturing Gradient Gel Electrophoresis) profile and sequence showed that Bacillus spp. and Pseudomonas spp. decreased after 4~5-year continuous cropping, which was similar to the actual period during which continuous cropping obstacles commonly occur(mainly 5~10 years). Soil organic carbon and C/N ratio significantly increased with the extension of continuous cropping time, and soil microbial C and N were a logarithmic function of continuous cropping year(R2 were 0.20 and 0.30, respectively, P<0.001). Soil bacteria were significantly negatively correlated to soil C/N. Our investigation indicates that the occurrence of continuous cropping obstacles closely relates to the dynamic changes in these two dominant populations, suggesting that soil Bacillus spp. and Pseudomonas spp. play vital roles in maintaining soil ecology and soil health under long-term continuous cropping. |
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