Enriching Vermicompost by Nitrogen Fixing and Phosphate Solubilizing Bacteria

Changes in populations of microorganisms in the vermicompost in order to improving its quality has been the novel study topics in the field of organic fertilizer production. Present study was performed with aimed to possibility of changing in the content of nitrogen and phosphorus in the vermicompost and to determine some quality characteristics in vermicompost. In order to accomplish this goal, after the production of vermicompost, inoculums from Pseudomonas and Azotobacter bacteria genera were prepared, then bacteria inoculated to vermicompost beds, for 60 days at a temperature of 28 ° C storage, and biological and chemical factors were measured on days 0, 20, 40 and 60 in vermicompost. Results showed that with increasing incubation time, the population of bacteria, nitrogen, available phosphorus, ash and humic acid increased, and the amount of organic carbon, EC and pH decreased. During incubation, Azotobacter and Pseudomonas treatments increased N content about 80 and 20 percent and P content about 25 and 40 percent, respectively. According to results of this study, 45 to 60 day incubation period could have very good results on the chemical and biological properties in vermicompost, but this effect is not significant in less than 40 days and more than 60 days. Bacteria which used in the present study had beneficial and different effects and depending the requirement could be used for vermicompost enrichment.