Effects Of TM On Yields And Microflora In Soil Under Flowering Chinese Cabbage Continuous Cropping In Greenhouse

Flowering Chinese cabbage(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee)is improtant local vegetables with unique flavor,excellent taste,wide adaptability in South China,and it can be planted and supplied throughout the year.Single variety and high multiple cropping index in the greenhouse caused serious continuous cropping obstacles,which led to serious diseases,insect pests,yield reduction,degraded quality,harmful microbe accumulation,physical and chemical properties deterioration in soil.The effects of different concentrations of TM on the yields,quality,soil enzyme activity and physicochemical properties of flowering Chinese cabbage were studied.There were four treatments,including spraying water on soil as the control(CK),spraying diluted the microbial fertilizer(TM)on soil as the treetments(T1-1: 500,T2-1: 1000,T3-1: 1500).The optimum concentration of nutrient in soil and mineral elements content in plants were analyzed,moreover,abundance and community structure difference of bacteria and fungi were studied through high-throughput sequencing technique.The main results of this study were as following:1.Stem length and stalk diameter in the different growth periods of flowering Chinese cabbage were improved by different concentrations of TM,thus increasing the fresh and dry weight of plants.The treatment of T1 was significally improved in commodity harvest period and T3 treatment only was promoted at the early growth stage.2.Different concentrations of TM significantly improved the contents of Vc,soluble sugar and soluble protein at the late growth stage.Among these treatments,T2 treatment is the best.3.The soil enzyme(urease,sucrase,neutral phosphatase,catalase)activities at different growth stages could be significantly increased by different concentrations of TM,and the soil enzyme activities of T1 in the leaf growth period,T1,T2 and T3 in the period of stalk formation and T1 and T2 in commodity harvest period were significantly increased.The soils treated by different concentrations of TM were generally higher than those of background.4.Different concentrations of TM could improve pH value,reduce the EC value in soil,and T2 treatment was the best;moreover,T2 and T3 treatments significantly increased soil porosity,decreased bulk density.5.The application of TM could significantly improve the contents of soil organic matter,nitrogen and exchangeable calcium,and could reduce the content of soil phosphorus.The contents of total nitrogen,total phosphorus,total potassium and exchangeable calcium were not significantly different from those of CK.The absorption of N,P and Mg in the plants were also significantly improved of TM.6.The results of high-throughput sequencing showed that the community structure of bacterial and fungal varied in different treatments at different times.Compared with the control,TM could increase diversity index of bacteria,and decrease the diversity index of fungi in soil.There were significant differences in the Alpha diversity index between the two treatments in leaf growth period.At the bacterial phylum level,the dominant bacteria in the background soil were Proteobacteria,Firmicutes and Actinobacteria,Gemmatimonadetes,Chloroflexi,while in control and TM,they were Proteobacteria,Bacteroidetes,Actinobacteria,Gemmatimonadetes,Chloroflexi.At the fungal phylum level,Ascomycota,Basidiomycota,Zygomycota,Ascomycota in the background and rhizosphere soil were dominant.Moreover,TM increased the relative abundance of most bacteria,and reduced the relative abundance of harmful fungi and the propagation of soil harmful bacteria.PCA analysis showed that TM had significant effects on soil bacterial and fungal community structure.The members of bacterial community in the rhizosphere soil between control and treatment were significantly different at the leaf growth stage and the flower stalk formation stage.Fungal community composition differed in the whole growth period.In conclusion,compared with the control,different concentrations of TM could increase the yield,improve quality,enhance soil enzyme activity,and soil physicochemical properties of flowering Chinese cabbage,T2 treatment was the best,which could improve the soil nutrients,the absorption of mineral elements,the abundance and diversity of soil bacteria,and reduce the abundance and diversity of harmful fungi,thus play the key role in the repairing continuous cropping obstacles of facility.