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| Effect of green manure and reduced chemical fertilizer load on the community of soil nitrogen-fixing bacteria |
| Received:April 17, 2018 |
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| KeyWord:green manure;fertilizer reduction;nitrogen-fixing bacteria;real-time PCR;high-throughput sequencing;community structure |
| Author Name | Affiliation | E-mail | | FANG Yu | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | WANG Fei | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | JIA Xian-bo | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | LIN Chen-qiang | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | ZHANG Hui | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | CHEN Long-jun | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | | | CHEN Ji-chen | Institute of Soil and Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China | chenjichen@163.com |
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| Abstract: |
| Chinese milk vetch (MV) is a type of green manure that has the potential to replace a portion of the chemical fertilizer load; however, it remains unclear how MV would replace N fertilizer. This study was conducted at a long-term field experimental station in Fuzhou, China. The treatments conducted for this study are CK (without fertilization), NPK (chemical fertilizer), MF80 (MV plus 80% NPK), MF60 (MV plus 60% NPK), and MF40 (MV plus 40% NPK). Soil samples were collected from the 0~20 cm soil layer at the rice tillering stage. We determined the soil physicochemical properties. The abundances and community structures of nitrogen-fixing bacteria were assessed using the nifH gene. Quantitative PCR and Illumina MiSeq sequencing were used to determine the abundance and community structure of nitrogen-fixing bacteria in the paddy soil. The results showed that there was no significant difference in the rice yield between the green manure treatments and NPK treatment. MF60 is an appropriate fertilization regime when considering the yield and application rates of chemical fertilizer. Long-term application of green manure combined with a reduced chemical fertilizer load increased the total nitrogen content in comparison with the NPK treatment, and there was no significant difference in the available nitrogen content between the green manure treatments (except for MF60) and NPK treatment. Compared with the NPK treatment, the green manure treatments (except for MF40) increased the abundance of nitrogen-fixing bacteria, and positive correlations between the bacterial abundance and available nitrogen, nitrate nitrogen, and pH were observed. Shannon indices of the nitrogen-fixing bacteria with the green manure treatments were lower than that with the NPK soil, but there was no significant difference in the operational taxonomic unit (OTU) number. Proteobacteria was the dominant phylum for all treatments, and NPK treatment led to a higher relative abundance of Proteobacteria than the green manure treatments. Principal coordinate analysis demonstrated that the community structures of nitrogen-fixing bacteria with the green manure treatments were significantly distinct from that with the NPK treatment. Our results indicated that green manure combined with reduced chemical fertilizer load could increase soil fertility and the abundance of nitrogen-fixing bacteria. Application of MV and application rates of chemical fertilizer are both important factors in shaping the community structure of nitrogen-fixing bacteria in the paddy soil studied. |
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