The Long-term storage of Rhizobial biofertilizer made from -sterilized carriers

Tejima, Kohei; Yokoyama, Tadashi*; Sato, Katsuya; Narumi, Issei

The inoculants survival in the biofertilizer could be affected by the physical and chemical properties of carrier materials and by the competition with native microbes in the carrier. -irradiation is expected to sterilize the carrier materials without changes in physical and chemical properties. In an effort to demonstrate the effectiveness of -sterilization, the survivals of inoculants were monitored to assess the shelf life of biofertilizer. The inoculants density after 12-month storage was greater than the initial density in biofertilizers made from sterilized carriers, while that was significantly decreased in biofertilizers made from non-sterilized carriers. -sterilization was superior to autoclave-sterilization in enhancing the survival of inoculants. Because of the stability of supply, the high sterilization effect with lower radiation doses, and the high performance in maintaining the inoculants density, "Keto-tsuchi" was selected as one of the most suitable for a biofertilizer's carrier.