16S rDNA sequencing reveal synergistic effects of silkworm feces and earthworms on nutrient-poor soil microbial community structure and function in Guangxi

Abstract

This study evaluates the synergistic effects of silkworm feces and earthworms on nutrient-poor acidic red soils in Guangxi, China. Using 16S rDNA amplicon sequencing, soil samples from untreated fields, silkworm feces, earthworm gut contents, and soils treated with silkworm feces combined with three earthworm densities (50, 80, and 110 worms/kg) were compared. The earthworm gut microbiome increased in diversity in a density-dependent manner, while treated soils displayed enhanced microbial richness—with the 80 worms/kg treatment showing the highest diversity (605 genera). Random Forest analysis identified key bacterial genera, and co-occurrence networks pinpointed potential keystone taxa. PICRUSt2 predicted enrichment of pathways for xenobiotic biodegradation, carbohydrate metabolism, and secondary metabolite biosynthesis. These findings demonstrate that integrating silkworm feces with an optimal earthworm density improves soil microbial diversity and function, offering insights for sustainable organic waste management and soil health.