Silicon Fertilizer and Microbial Agents Changed the Bacterial Community in the Consecutive Replant Soil of Lilies

Abstract

Crop replanting leads to soil degradation and soil productivity reduction, which is a challenge for sustainable agricultural development. We previously found that silicon fertilizers combined with additional microbial agents are an effective means to alleviate problems that occur in a variety of Chinese lily during replanting, but little is known about the changes in microbial structure during this process. In the present study, we applied four treatments: CK (control), SF (silicon fertilizer), MF (microbial agents), and SMF (combination of silicon fertilizer and microbial agents). We treated the soil constantly for three years and investigated the bacterial community structure and some specific microbial groups in the soil of the lily root zone using 16S rRNA high-throughput sequencing analysis. The results showed that silicon fertilizer and microbial agent treatment significantly improved the growth status of the plants and changed the diversity and structure of the bacterial community in the soil. The genus Pseudomonas significantly increased in the SF treatment, and the phylum Actinobacteria and the genera Nordella, Devosia, and Rhodoplanes significantly increased in the SMF treatment. The genera Nordella, Pedomicrobium, and Chthoniobacter correlated with the seedling index or available silicon content. In addition, the two genera Gaiella and Nocardioides were the key species linking the bacterial community in the soil. The soil physicochemical properties played an important role in restoring the soil bacterial community structures. In conclusion, silicon fertilizer and microbial agents changed the diversity and structure of the bacterial community. Under the fertilizer supplement model, the enrichment of the phylum Actinobacteria and the genus Pseudomonas played an important role in improving soil health and alleviating CRPs in lilies. In addition, organic matter, available phosphorus, available potassium, and available silicon were found to be the most important factors that have a great impact on the restoration of bacterial community structures.