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Abstract

Compost enrichment with nitrogen fixing Azotobacter is a method to enhance the used of biofertilizer in sustainable agriculture. The objective of a laboratory experiment was to verify the change in Azotobacter and total bacteria population in two kind of compost after inoculation with nitrogen fixing A. chroococcum. The experiment was setup in completely randomized design with four combination treatments of sterilized and unsterilized composted manure as well as vermicompost. The control treatments are the sterilized one. The results verified that irrespective of treatments, Azotobacter enrichment increased Azotobacter but reduced total bacteria population after 18-day incubation compared to the composts before treatment. At the end of experiment, the population of Azotobacter in both sterilized and unsterilized vermicompost were slightly lower than in manure; but the count total heterotroph bacteria in both organic matter was similar. The acidity of both enriched compost was neutral while their humidity was declined to 18-19% at the end of experiment. This experiment showed that inoculating the compost with Azotobater maintain the Azotobacter count but decline the total bacteria. This suggested that negative interaction between Azotobacter and other heterotroph bacteria in compost might be occured. Contribution/Originality:This study is one of very few studies about the viability of total bacteria and Azotobacter in Azotobacter-enriched compost. Compost enrichment with Azotobacter enhanced Azotobacter population but decreased total bacteria decreased in the compost. This enriched compost can serve as organic matter and Azotobacter inoculant once introducing to the soil.