| Poyang Lake is the largest freshwater lake in China, the periodic change of water level, the wetland vegetation types by aquatic plant communities to wetland plant communities in seasonal succession, to carry out vegetation community succession and the level of organic carbon and microbial effects, in order to understand plant succession and the changing process of water level of organic carbon in the micro ecological mechanism and provide a theoretical reference for revealing the Poyang Lake soil carbon stability and microbial transformation mechanism. This paper selects the two typical wetlands of Poyang Lake- Nanjishan wetland and Changhuchi wetland as the study areas, analysis of different vegetation communities(Phragmites australis(Cav.) Trin. ex Steud, Triarrhena lutarioriparia L. Liou, Zizania latifolia(Griseb.) Stapf, Carex cinerascens, and bare mudflat as a control) and different water level period(the normal water period, dry season and wet season) soil physical and chemical nature, enzyme activity, carbon content and microbial community diversity of variation characteristics of. The main results are as follows:(1)The different vegetation communities, different water level period and different areas, soil enzyme activities have some differences. Different vegetation soil catalase activity with the elevation of the lower assumes the trend of elevated(in addition to Phragmites australis(Cav.) Trin. ex Steud-Triarrhena lutarioriparia L. Liou community). Urease activity without significant difference, invertase activity in the Phragmites australis(Cav.) Trin. ex Steud-Triarrhena lutarioriparia L. Liou community was the highest and others have significant difference(P?0.05). Different water level period soil enzyme activity were significant difference(P?0.05), which catalase activity for wet season>the normal water period>dry season, urease activity for dry season>the normal water period>wet season, invertase activity for dry season> wet season> the normal water period.(2)Different vegetation communities, water level of soil organic carbon content is different. The content under the different vegetation soil MBC and DOC have no significant difference, and the content of LOC in Phragmites australis(Cav.) Trin. ex Steud-Triarrhena lutarioriparia L. Liou community and Zizania latifolia(Griseb.) Stapf community were significantly higher than that of other content(P?0.05). In different water level MBC content had no significant difference, and DOC and LOC content in the dry season were significantly higher than that of other water period(P?0.05).(3)Different vegetation community and water level, soil microbial community structure and diversity are different. The main phylum was detected in soil are: Chloroflexi, Proteobacteria, Acidobacteria, Nitrospirae, Actinobacteri, Firmicutes. the proportion in different vegetation and different levels of period of Chloroflexi and Proteobacteria were higher. Microbial diversity analysis found that under different vegetation types had significant difference(P?0.05) in Zizania latifolia(Griseb.) Stapf and Carex cinerascens, communities in the soil microbial diversity is higher. The water level in different period no significant differences, but the wet period of soil microbial diversity is highest.(4)The water content, temperature, pH and so on have the remarkable influence in the soil enzyme activity, the organic carbon active component content as well as the microbial community structure, the diversity. The increase of water content and the increase of temperature would promote the activity of catalase, but the increase of p H would inhibit the activity of urease and invertase. The increase of temperature will decrease the content of DOC and LOC, and the increase of pH will decrease the content of MBC, DOC and LOC. The increase in water content would inhibit the green bend, but it would promote the diversity of soil microbes. |
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