Enhancing lettuce growth and rhizosphere microbial community with Bacillus safensis YM1 compost in soilless cultivation: An agricultural approach for kitchen waste utilization

Abstract

To evaluate the effect and mechanism of inoculant compost on vegetable growth under soilless culture, romaine lettuces were planted in the growing media with different volume ratios of Bacillus safensis YM1 compost. The results demonstrated that the physical and chemical characteristics of the growing media containing B. safensis YM1 compost supported the lettuce growth. The recommended ratio for YM1 compost addition was 20–40%. The addition of YM1 compost dramatically affected the microbial community richness and composition in the lettuce rhizosphere media, with a total of 254 and 97 biomarker taxa for the bacterial and fungal communities, respectively. The enrichment of some beneficial microbial groups (Bacillus) and the inhibition of harmful microorganisms (Acremonium, Plectosphaerella, and Penicillium) increased the nutrient cycling of the rhizosphere media microenvironment, which is a crucial factor for YM1 compost to promote lettuce growth. Here, we provide evidence that YM1 compost was safe and hygienic, free of heavy metals and common infectious pathogens, and that it may be used in agriculture. The findings could serve as a scientific basis for formulating an application standard for growing media derived from inoculant compost.