Application of thermotolerant microorganisms for biofertilizer preparation

Background and Purpose: Intensive agriculture is practised in Taiwan, and compost application is very popular as a means of improving the soil physical properties and supplying plant nutrition. We tested the potential of inoculation with thermotolerant microorganisms to shorten the maturity and improve the quality of biofertilizer prepared by composting. Methods: Thermotolerant microorganisms were isolated from compost and reinoculated for the preparation of biofertilizer. The physical, chemical and biological properties of the biofertilizer were determined during composting. The effects of biofertilizer application on the growth and yield of rape were also studied. Results: Among 3823 colonies of thermotolerant microorganisms, Streptomyces thermonitrificans NTU-88, Streptococcus sp. NTU-130 and Aspergillus fumigatus NTU-132 exhibited high growth rates and cellulolytic and proteolytic activities. When a mixture of rice straw and swine manure were inoculated with these isolates and composted for 61 days, substrate temperature increased initially and then decreased gradually during composting. Substrate pH increased from 7.3 to 8.5. Microbial inoculation enhanced the rate of maturity, and increased the content of ash and total and immobilized nitrogen, improved the germination rate of alfalfa seed, and decreased the content of total organic carbon and the carbon/nitrogen ratio. Biofertilizer application increased the growth and yield of rape. Conclusions: Inoculation of thermotolerant and thermophilic microorganisms to agricultural waste for biofertilizer preparation enhances the rate of maturity and improves the quality of the resulting biofertilizer. Inoculation of appropriate microorganisms in biofertilizer preparation might be usefully applied to agricultural situations.