Changes in labile phosphorus forms during maturation of vermicompost enriched with phosphorus-solubilizing and diazotrophic bacteria.

The aim of this study was to assess the effect of N(2)-fixing and P-solubilizing bacteria during maturation of vermicompost on phosphorus availability. A bacterial suspension containing Burkholderia silvatlantica, Burkholderia spp. and Herbaspirillum seropedicae was applied at the initial stage of vermicomposting. At the end of the incubation time (120days), the nitrogen content had increased by18% compared to uninoculated vermicompost. Water-soluble P was 106% higher in inoculated vermicompost while resin-extractable P increased during the initial vermicomposting stage and was 21% higher at 60days, but was the same in inoculated and uninoculated mature compost. The activity of acid phosphatase was 43% higher in inoculated than uninoculated vermicompost. These data suggest that the introduction of the mixed culture had beneficial effects on vermicompost maturation.