Effect of organic and inorganic additives on some chemical properties of vermicompost, earthworm’s biomass and reproduction

ABSTRACT-The enrichment of bedding for vermicomposting systems with organic and inorganic additives is a technique which can promote the quality of produced vermicompost. Phosphate rock and fishmeal are two available and low-cost substances which can be provided easily and inoculation of vermicompost with phosphate solubilizing microorganisms (PSMs) can enhance the availability of their nutrients. In this research, the effect of using phosphate solubilizing bacteria (PSB) (Pseudomonas fluorescens) by adding phosphate rock (0 and 1% W/W) and fishmeal (0 and 1% W/W) on some chemical and biological properties of vermicompost was studied under greenhouse conditions with a factorial arrangement in a completely randomized design with three replications. Phosphate rock application and PSM inoculation decreased N concentration while fishmeal increased it. P concentration increased by adding phosphate rock, fishmeal or PSB or their co-applications. Fishmeal increased micro-nutrients concentration except for Fe. Phosphate rock increased Fe concentration and decreased other micro-nutrients concentration. Electrical conductivity (EC) increased by adding phosphate rock but decreased by fishmeal application. Phosphate rock and fishmeal increased pH. Phosphate rock and PSB decreased the number and weight of earthworms and the number of cocoons. Fishmeal application increased the number and weight of earthworms and number of cocoons. Results indicated that enrichment of vermicompost bedding by additives could increase some essential nutrients and change the growth and biomass of earthworms.