Microbial activity was greater in soils added with herb residue vermicompost than chemical fertilizer

Herb residue vermicompost is thought to have high agriculture value, while its effects on soil microbial activities have not been fully understood. Here, soil microbial biomass, respiration and enzyme activities in soil planted with maize were compared among treatments amended with herb residue vermicompost at rates of 25, 50, 75 and 100 g kg−1, chemical NPK fertilizer and no fertilizer (the control). Our results showed that soil microbial biomass carbon, respiration, and alkaline phosphatase, urease, and invertase activities were greater in soil amended with herb residue vermicompost than the unfertilized control (P <0.05). Compared with chemical fertilizer, herb residue vermicompost increased soil urease and alkaline phosphatase activities at each application rate, promoted soil respiration and microbial biomass carbon at the application rates of 50, 75 and 100 g kg−1, and increased soil inverse activity at the application rates of 75 and 100 g kg−1. In conclusion, herb residue vermicompost supported greater soil microbial biomass, respiration and enzyme activities than conventional NPK fertilizer, and the effect was larger when higher rates of herb residue vermicompost were added.