复合微生物菌肥KMM减缓苹果再植病害机制

为揭示木美土里复合微生物菌肥（Kimidori microbial manure，KMM）促进再植苹果树的生长及减缓苹果再植病的作用机制，采用土壤常规农业化学分析法和Illumma MiSeq高通量测序技术比较分析KMM和常规有机肥（对照）处理后再植苹果树的生长指标、理化因子、根际土壤酶活性以及细菌群落结构和功能的变化。结果表明，施用KMM后，果树的株高增长率、干径增长率、叶绿素含量、分枝个数和分枝长度等生长指标均显著升高，有机质含量显著增加，中性磷酸酶、脲酶、蔗糖酶和过氧化氢酶活性均显著提高，同时增加了再植土壤细菌群落的丰富度和多样性。从采集土壤中分离得到51株细菌并进行盆栽试验，其中经KMM-15、KMM-37和KMM-50菌株处理后海棠苗叶绿素含量、株高、茎粗均显著提高，经鉴定这3株菌株为贝莱斯芽胞杆菌Bacillus velezensis。表明春秋2次施用KMM提高了土壤有机质含量和酶活性，并重塑了根际土壤中细菌群落结构，进而缓解苹果再植病害发生程度，促进果树生长。

The mechanism of compound microbial fertilizer KMM alleviating apple replant disease

To reveal the mechanism of Kimidori microbial manure (KMM) promoting the growth of replanted apple trees and alleviating apple replant disease, the changes of growth indexes, physical and chemical factors, rhizosphere soil enzyme activities, structure and function of bacterial community in the rhizosphere of replanted apple trees treated with KMM and conventional organic fertilizer were compared and analyzed with soil conventional agricultural chemical analysis and Illumma MiSeq highthroughput sequencing. The results showed that the growth indexes such as plant height growth rate, stem diameter growth rate, chlorophyll content, branch number and branch length of fruit trees were significantly increased after the application of compound microbial fertilizer. The organic matter content was significantly increased, and the neutral phosphatase, urease, invertase and catalase were also significantly increased. At the same time, the richness and diversity of bacterial community in replanted soil were increased. Fifty-one bacterial strains were isolated from collected soil and subjected to pot experiments. The chlorophyll content, plant height, and stem diameter of potted begonia seedlings treated with strains KMM-15, KMM-37 and KMM-50 were significantly affected. The three strains were identified to belong to the bacterial species Bacillus velezensis. The application of KMM in spring and autumn increased soil organic matter content and enzyme activity, and reshaped the bacterial community structure in rhizosphere soil, thereby alleviating replanting disease and promoting growth of the apple trees.