Effects of two species of earthworms (Allolobophora spp.) on soil systems:: a microfaunal and biochemical analysis

In this work we studied how earthworm digestion affects both soil biochemical and microfaunal characteristics. We sampled paired fresh casts and bulk soil of two earthworm species, Allolobophora caliginosa and A. molleri, inhabiting a pasture and a riverside, respectively. We focused on the differences in faunal composition and biochemical characteristics between cast and bulk soil. Ammonium and carbohydrate contents were higher in casts than in the surrounding soil. DON content was lower in the casts than in the surrounding soil. Microbial biomass (measured as microbial biomass-N, arginine ammonification and SIR) and microbial activity (measured as basal respiration, P-glucosidase, alkaline phosphatase, dehydrogenase and protease) were also higher in casts in the surrounding soil than. Flagellate protozoa and nematode numbers were lower in A. caliginosa casts and higher in A. molleri casts than in the surrounding soil.