Study On The Microbial Community Structure In The Three Different Kinds Of Purple Soil Pond Mud

“Keeping the water well is the beginning of fish culture,but making the pond mud well is the beginning of keeping water well.”According to it,the pond mud management is the key to the pond water quality control.Thus,the microbial community structure in the ponds based on different kinds of soil would be different.In the present study,three different kinds of purple soil(S₁ fromed Jiaguan group?K₂j?,S₂fromed Shaximiao group?J₂s?,S₃ fromed Penglaizhen group?J₃s?)were used as the pond mud to study the changing characteristics of the physical-chemical properties and microorganism community structure in the soil after fish culture.This study could provide a basis for evaluating which kind of purple soil would be more conducive to aquaculture.Control groups(S_1-0,S_2-0,S_3-0)were the three kinds of soil submerged by water,while the experimental groups(S_1-1,S_2-1,S_3-1)were soil submerged with fish feeding in the overlying water.The results were as follows:1. The characteristics of the three kinds of purple soilThe three kinds of purple soil?S₁,S₂,S₃?respectively were acid purple soil,neutral purple soil and calcareous purple soil.The organic matter in S₁ is significantly lower than that in S₂ and S₃?P<0.05?.The contents of total nitrogen?TN?and total phosphorus?TP?in the three kinds of purple soil were S3>S2>S1,and S₁ is far less than the latter two.With Comprehensive comparison,The content of major elements?N+P+K+Ca+Mg+S?in the three was S3>S₂>S₁,while microelements?Fe+Zn+Mn+Cu+B?was S2>S1>S3.2.The changes of physical-chemical properties of the pond mud?1?Temperature changing trend of pond mud roughly liked the temperature of air,and variation range was 23-31?.?2?The pH of all treated pond mud went down firstly,and then maintain a relatively stable state without S_1-1;The pH of feeding groups was neutral and higher than the controls.The O.R.P of S_1-0 alternate down and up in a relatively stable range,S_2-0 and S_3-0 were much liked the early of S_1-0.After interim,they two changed to be minus.S_1-1,S_2-1 and S_3-1 were minus from the beginning.?3?The contents of organic matter,TN and TP in all treated groups were increased,but the rising trend of control group was weaker.The contents of organic matter,TN and TP were the lowest in the S_1-1,the content of organic matter was S_2-1>S_3-1,the content of TP was S_3-1>S_2-1;the content of TN was higher in the early stage of experiment,but S_3-1 was higher later.?4?In the feeding treated groups,the accumulation of organic matter,TN and TP in S_3-1 was relatively low.The deposition of TN and TP in S_1-1 was higher than those in S_2-1 for most of the time,while the deposition of organic matter in S_2-1 was significantly higher than that in S_1-1.3.The microbial community structure and quantitative features of pond mud?1?The microbial density in each groups all decreased gradually.In addition to S_1-0,the microbial community diversity in other groups were increased.Under the feeding condition,the microbial density S_3-1>S_2-1>S_1-1,the species diversity index S_2-1>S_3-1>S_1-1,and There was no significant difference in species evenness index.In general,the microorganism communities diversity in the group S_1-1 was poorer.?2?After high-throughput sequencing analysis,microorganisms of 53 phylums had been detected in 6 groups pond muds?18 samples?.The dominant phylum was Proteobacteria.Streptomyces,Bacillus,Elusimicrobia,Green Bacteroides,Warts Microflora,Clostridium,Nitrobacteria,Actinomycetes,Spirochetes,Latscitacteria,etc.more than 10 phylums also relatively high.The results also suggested that about 6043OUTs had been detected,of which 764 species can be classified to the genus,175species can be classified to the species and the majority have not been defined or studied yet.There were 38 genera in the top 10 microbes of per experiment group,with more than 45.8%of the coverage.?3?The results of redundancy analysis showed that the microbial community diversity index?Observed-Species and Shannon Index?and the evenness index?Simpson Index and Pielou Index?of pond mud derived from three kinds of purple soils had a significant positive correlation with the content of pH,organic matter,TN and TP and negatively correlation with O.R.P.Most microbiological proportions were positively correlated with the contents of pH,organic matter,TN and TP,and negatively correlated with O.R.P,which a small number of microbiological proportions were contrary to.?4?Few kinds of probiotics?Bacillus,Nitrifying bacteria and Actinomycetes,etc.?and pernicious bacteria?Flavobacterium,Enterobacter,Aeromonas,Pseudomonas,etc.?were detected in the pond mud?6 treatments?derived from three kinds of purple soils,and the proportion of which was S_2-1>S_3-1>S_1-1 and S_2-1>S_1-1>S_3-1 respectively.