Analysis Of Soil Bacterial Community Structure In Different Ginger Fields And Study On The Effect Of Fertilization

To reveal the structure and diversity of soil bacterial communities in ginger plantation soil,we collected soils from 5 sites in the main big ginger producing regions,including Laiwu,Anqiu,Changyi in Shandong Province and Fengrun,Funing in Hebei Province in the north of China.Bacterial community structure and diversity of soil were assessed by performing a 16 S ribosomal DNA(r DNA)sequence analysis of DNAs extracted from soil of ginger fields.And the effects of soil properties on the structure of bacterial community were also estimated.As results,45 bacterial phyla were detected,in which Proteobacteria,Acidobacteria,Chloroflexi,Actinobacteria and Gemmatimonadetes were dominant.The highest values of bacterial richness were found in sites Fengrun and Funing,and the lowest in Anqiu.The results of CCA(Canonical Correlation Analysis)by forward selection showed that the bacterial diversity and community composition in ginger fields is highly correlated with the contents of available nitrogen(AN)and total carbon(TC),with the contribution of 53.5% and 37.0%,respectively.The pattern of microbial diversity and abundance is markedly different in different sites,and specialized bacterial groups within each region of sample were recorded.In order to further verify the law found in field investigation and explore the factors affecting the soil bacterial community structure of ginger,field experiments with different fertilization treatments of ginger were carried out.The growth,yield,nutrient absorption and distribution of ginger under different fertilization conditions were investigated and compared,and the soil nutrients,soil enzyme activities and soil bacterial community structure after harvesting ginger were analyzed.The results showed that under the same conditions,increasing the amount of fertilizer could not increase the yield of ginger,and reducing the amount of fertilizer by 20% would not affect the yield of ginger,but reducing the amount of fertilizer by 40% would reduce the yield of ginger.The total nitrogen,phosphorus and potassium uptake of ginger plant was K > N > P,in which the contents of nitrogen and potassium were higher in ginger stems and leaves,and the contents of phosphorus were higher in ginger chunks.Moreover,ginger is sensitive to potassium fertilizer,and the higher potassium fertilizer application rate,the higher potassium content of ginger plants.Excessive fertilization results in a significant decrease in soil p H,a decrease in soil sucrase activity,and a decrease in the decomposition and utilization of soil organic matter.However,the activities of soil urease and nitrate reductase in the process of nitrogen cycle were directly proportional to the amount of fertilizer applied.The excessive nitrogen fertilizer was neither absorbed by the plant nor accumulated in the soil,while P and K fertilizer accumulated in the soil.The community structure and diversity of soil bacteria in fertilization experiment were analyzed.The results showed that only in one cultivation season of ginger,the different application rates still had a certain influence on the composition of soil bacterial community.Although there was no significant change in the species composition of soil bacterial community under different treatments,excessive application rates caused a decrease in the abundance and diversity of soil bacteria.The soil with more fertilizer was enriched with more bacteria involved in nitrogen cycling,while the soil with less fertilizer was enriched with more bacteria involved in decomposition of organic matter and formation of humus.The results indicated that the amount of fertilizer and the type of fertilizer played an important role in shaping the soil bacterial community structure and the specific population of bacteria,and the amount of nitrogen fertilizer had the greatest effect on the soil bacterial community structure and the specific population of bacteria.