Enhanced bio-composting of rice straw using agricultural residues: an alternate to burning

Purpose Rice straw which predominantly contains cellulose, hemicellulose and lignin, can be converted into value-added product such as bio-compost. The present study was planned to carry out rice straw degradation, added with agricultural residues like rice bran and fruit waste in different combinations, with standard fungal culture of Trichodermaharzianum MTCC 8230. Methods Rice straw added with fruit waste and rice bran was moistened with sterilized water in five different proportions. The experimental trays were inoculated with spore suspension (1 x 10(8) spores/ml) of T. harzanium. The trays were observed for change in pH, appearance and chemical fibres (acid detergent fibre, neutral detergent fibre, and acid detergent lignin). Results A continuous increase in bulk density accompanied with a decrease in volume was observed in all the experimental trays including the control. There was an initial increase in pH from 7 to 9 which stabilized to 8 after 12 days of incubation. The crystalline structure of rice straw was transformed into amorphous one in a time frame of 28 days, with a significant decrease in lignin from 20-25% to 13-15% and an increase in crude protein from 5-17%. Conclusion The crystalline rice straw was reduced to a brown crumpled and compact value-added composted biofertlizer with a high carbon and crude protein content.