Effects Of Organic Fertilizer On Two Soil-borne Diseases And Soil Microbial Community Of Brassica Pekinensis

Brassica pekinensis(Lour.)Rupr.is a biennial herb of Brassica genus in Cruciferae.It has rich nutritional value and is widely cultivated in all parts of China,and is one of the important vegetables in China.In view of the current situation of unreasonable fertilization and chemical abuse of Brassica pekinensis(Lour.)Rupr.,combined with the national agricultural development concept of "one control,two reduction and three basics",a field experiment was carried out in Changsha County of Hunan Province in 2020 to explore the effects of organic fertilizer on the growth,nutritional quality,occurrence of soil borne diseases,soil chemical properties and soil microbial community of Brassica pekinensis(Lour.)Rupr.,so as to provide reference for the application of organic fertilizer in Brassica pekinensis(Lour.)Rupr.production The application of organic fertilizer can provide a theoretical basis for the control of soil borne diseases.The conclusions are as follows.1.The effect of Fertilization on the yield of Brassica pekinensis(Lour.)Rupr.was obvious,and the increase range was 34.14% ～ 47.96%.Only organic fertilizer production is lower than the conventional fertilization treatment inorganic fertilizer(all),but the organic fertilizer partly replace inorganic fertilizer for cabbage yield no significant differences.2.Organic fertilizer had a significant effect on the improvement of nutritional quality of Brassica pekinensis(Lour.)Rupr.Organic fertilizer could improve the content of vitamin C and chlorophyll and reduce the content of nitrate in Brassica pekinensis(Lour.)Rupr to a certain extent,but had no obvious effect on the content of soluble sugar and water content in Brassica pekinensis(Lour.)Rupr.3.Through the investigation of black spot and soft rot of Brassica pekinensis(Lour.)Rupr,it was found that fertilization could reduce the incidence.Compared with blank control treatment,the control effect of conventional fertilizer treatment(all inorganic fertilizer)on black spot and soft rot of Brassica pekinensis(Lour.)Rupr was 5.63% and 11.59%,respectively.Only organic fertilizer processing of cabbage black rot and soft rot control effects were 41.49% and 44.32%;The best treatment was combined application of organic fertilizer and inorganic fertilizer,and the control effect on black spot and soft rot of Brassica pekinensis(Lour.)Rupr reached 48.46% and 51.52%.4.According to the analysis of soil chemical properties,the application of inorganic fertilizer will reduce the content of organic matter in the soil,make the soil p H drop,and cause soil acidification.Compared with blank control,organic fertilizer application increased soil nutrient organic matter by 3.76%,total K by 9.08%,base N by 1.45%,available P by22.41% and available K by 9.77%.5.Cabbage planting can increase the relative richness and diversity of soil fungal community and decrease the relative richness and diversity of soil bacterial community.Application of organic fertilizer can improve the richness and diversity of fungal and bacterial communities in soil,while only application of inorganic fertilizer can reduce the richness and diversity of fungal and bacterial communities in soil.The application of organic fertilizer to control black spot and soft rot of Chinese cabbage was related to the improvement of soil microbial community and the increase of the relative richness of Nitrospirae,which is related to nitrogen fixation.In addition,the control of black spot of Chinese cabbage was also closely related to the reduction of the relative richness of pathogenic microorganism Alternaria in soil.