Effects Of Anaerobic Soil Disinfestation On Soil Improvement And Bacterial Wilt Control

Tomato(Solanum lycopersicum),as one of the world's highest vegetable production types,with the fruit of the dish's reputation and fruit nutrient-rich,is one of the main varieties of cultivated vegetables in China's agricultural production.However,the current crop intensification and monoculture cause continuous cropping obstacles,soilborne disease outbreak,soil degradation etc,seriously restricting the sustainable production of tomato.In this study,anaerobic soil disinfestation(ASD)was used as a pathogen control method with different temperature,different carbon source to study the effects on soil improvement,control of soil bacterial wilt and tomato growth,which may provide theoretical basis and practical guideance for exploring efficient and environmentally friendly ways of controlling bacterial wilt.The main results are as follows:ASD treatment with rice bran under different temperature(25?,30?,35?)resulted in 100% reduction of bacterial wilt incidence compared with the contro l,which effectively increased tomato plant height,fresh weight and stem diameter,and higher temperature had more obvious promotion effects;ASD treatment significantly increase soil pH(0.75-1.07)and reduce soil Eh and EC;The amount of soil bacteria,actinomycetes and bacteria / fungi ratio were significantly lower than that of CK,but not for soil fungi.The amount of Ralstonia solanacearum in soil was also reduced significantly by 83.24% ~ 89.65% after ASD treatment under different temperature.ASD with rice bran(DRB),wheat bran(DWB),tea seed bran(DTB)and rice straw(DRS)application showed 100% controlling effect of bacterial wilt compared with CK,while single anaerobic treatment(D)only reduced pathogen incidence by 83.3%.All anaerobic treatments could greatly promote tomato growth except DRB.ASD treatme nt could significantly increase soil temperature,pH and conductivity,but reduce soil Eh.Moreover,soil organic matter,total nitrogen,available N and available K contents were increased,but soil total P and total Kwere not changed.The amount of Ralstonia solanacearum in soil decreased by 97.27% ~ 99.14% by ASD treatment and the amount of soil bacteria and actinomycetes were also significantly decreased.The bacteriostatic experiments showed that volatile compounds produced from ASD treatment had significant role in inhibiting Ralstonia solanacearum.16s rDNA sequencing analysis of soil bacteria showed that the number of tags in the DTB-treated group was significantly higher than that of CK,but the total OUT of DWB,DTB and DRS was significantly lower than CK.Soil in CK,D and DRB treatment groups had higher bacterial diversity(Shannon index,Simpson index,AC E and Chao 1 indices)than that in DWB,DTB and DRS treatments.Further analysis by principal component analysis and cluster analysis indicated alltreatments were different in species,abundance and diversity,respectively.Relative abundance of Crenarchaeota,Acidobacteria,Actinobacteria,C hloroflexi,Gemmatimonadetes and Proteobacteria in DWB,DTB and DRS treatments were reduced compared with than in CK,D and DRB,but Firmicutes(mostly anaerobic bacteria)increased significantly.In additions,the relative abundance of Burkholderiaceae and Ralstonia were significantly decreased after anaerobic soil disinfection.Therefore,the addition of wheat bran,tea seed bran and straw for ASD treatment could make great changes in soil bacterial communities.Field experiments showed that ASD could increase soil temperature,pH and soil Eh,and significantly increase Fv / Fm of tomato leaves,but had no significant effect on photosynthetic parameters.Compared with the control,ASD treatment could promote the growth of tomato and increase plant resistance.The incidence of bacterial wilt was reduced by 29.41 ~ 42.65%,the yield increased by 41.41 ~ 56.25%,and the content of sugar and acid,Vc and soluble protein increased.In summary,as a non-chemical,environmentally friendly soil disinfestation method,ASD plays an important in soil improvement,soil-borne disease control,tomato growth promotion,which is worth of popularization and application.