The Influence Of Cultured Turtle Introduction On Rice Growth,Yield And Soil Microbial Community

The integrated agri-aquaculture system?IAAS?has become one of the main directions for the sustainable development of agriculture because of its good ecological and environmental effects and the ability to produce green rice which meets the market demand for food safety.At home and abroad on the various farming patterns of soil bacterial community structure characteristics,especially the relevant functional gene bacteria group is relatively weak,become one of the factors limiting its promotion.Although the effects of integrated cropp ing patterns on soil bacteria have been studied,most of the relevant studies are subject to methods and techniques.The number and diversity of soil microbes in paddy field integrated breeding systems and the diversity of bacterial functional genes in paddy soils And its function is still less.Based on the model of rice-turtle co-culture,on the one hand,the paper analyzed the soil physical and chemical properties,rice growth index,rice yield and water content of paddy field under different system,so that to understanding the effect of “uninterrupted fertilization" and “the disturbance of animals” on the Ecosystem of rice-turtle co-culture,O n the other hand,we used the Illumina Miseq sequencing method based on 16 S r RNA gene and nifH gene to study the effect of aquaculture animals on the bacterial community structure and composition of paddy soil.The main research structure is as follows:1?Compared with the rice mono-culture?R-M?,the NH₄⁺,NO₃^-and PO₄^-concentrations of the paddy field in rice-turtle co-culture?R-T?were increased in the later stage of rice growth?34-109 days after rice transplantation?,the results showed that the soluble nutrients in paddy field were improved effectively.The rice yield and number of spikelets per effective panicle were significantly increased?P <0.05?R-T.The results showed that the difference of rice yield in the two models was mainly due to the difference in the number of spikelets per effective panicle.The seed setting rate of rice increased about 0.77%,the grain weight increased about 10.17%,the biomass accumulation of rice increased about 3.59%,and the tiller number increased about 8.90%.The results showed that the introduction of cultured turtle in paddy field could improve the soil nutrient content.2?Compared with the R-M,the contents of organic matter,available P,available K,total N,nitrate N and ammonia N in paddy soil were improved in R-T,The contents of nitrate N and ammonia N were significantly increased?P <0.05?.3?Compared with the R-M,the structure and composition of the bacterial community in the surface and rhizosphere soil of paddy field in rice-turtle co-culture were significantly different.The microbial enrichment and diversity of soils in the surface and rhizosphere soils of rice paddy field were improved.Compared with R-M,the relative abundance of chloroflexi,Nitrospirae and Acidobacteria increased and the relative abundance of Proteobacteria and Bacteroidetes was reduced in the surface soil of the R-T.In rhizosphere soil,compared with R-M,the relative abundance of Nitrospirae,?Bacteroidetes and Proteobacter increased,and the relative abundance of Chloroflexi and Acidobacteria reduced in R-T treatments.The main genera were Acidobacteria bacterium_uncultured ? Nitrosomonadaceae_uncultured ?Nitrospiraceae_uncultured ? Geobacter ? Gemmatimonadaceae_uncultured ? and Xanthomonadales_norank Under the two models,the relative abundance of Nitrospiraceae_uncultured and Geobacter in rhizosphere soil was significantly different?P<0.05?,and the relative abundance of Nitrosomonadaceae_uncultured?Nitrospiraceae_uncultured ? Gemmatimonadaceae_uncultured and Acidobacteria bacterium_uncultured in the surface soils was significantly different?P<0.05?.The analysis of O UT Venn diagram,PC A analysis and cluster analysis showed that the root and surface soil flora communities in paddy field had a significant difference after introduction of paddy field.Compared with paddy soil,Group structure and composition of the difference is more obvious.CCA analysis showed that the structure of soil microbial community had a good correlation with soil organic matter,available phosphorus,NO₃^--N and NH₄⁺-N contents.4?The results of High throughput Sequencing of nifH gene showed that the main nitrogen-fixing bacteria were classified as Bradyrhizobium ? Geobacter ?Anaeromyxobacter?Desulfovibrio?Sideroxydans,Desulfuromonas?Halorhodospira?Azotobacter?Desulfobulbus? Methylomonas?Pseudacidovorax and Azospirillum in the two modes,and it has differ proportion in different modes and sampling periods respectively.The introduction of cultured turtle significantly affected the diversity and abundance of soil nitrogen fixation bacteria in paddy soil,but these effects differed between the two models and the different growth stages.The diversity index and richness index of soil nitrogen fixation microbes were improved after the introduction of turtle.Rice growth period and model had an effect on nitrogen fixation microbial biomass in paddy soil,and the former had more influence.PC A and cluster analysis showed that the growth period and seedling pattern of paddy rice had an effect on soil nitrogen fixation microorganism in paddy field,and the former had a greater effect.