Seed coating by biofertilizer containing spores of Bacillus pumilus TUAT1 strain enhanced initial growth of Oryza sativa L.

In rice production, early growth is often slow in direct-seeded system. Techniques to overcome this barrier are needed. This study evaluated the effectiveness of Kikuichi-a biofertilizer containing Bacillus pumilus TUAT1 spore-in promoting rice growth in a direct-sowing system. Oxygen, iron, and molybdenum as coating materials were also evaluated to combine with biofertilizer. The seeds were coated with powdered Kikuichi with polyvinyl alcohol followed by a coating with calcium peroxide (CALPER), molybdenum (Benmoly), and iron powder. Double coating with the biofertilizer and Benmoly promoted plant growth. We applied amounts of Kikuichi equivalent to one, two and a half, and five times the weight of the seeds and found that the growth-promoting effect was dependent on the amount applied. The best timing of application of the coating, specifically during sprouting, was before the coleoptile emerged. Bacillus pumilus TUAT1 can enhance the growth of rice when it exists in high concentration on the spermosphere by coating with molybdenum, but double coating with neither calcium peroxide nor iron powder contributed to the initial growth of the seeds. Kikuichi coating with Benmoly has positive effects on the rice growth. This coating method is suitable to apply biofertilizer for direct sowing cultivation of rice.

Automated summary

This study found that the use of the biofertilizer Kikuichi containing Bacillus pumilus TUAT1 spores, combined with coating materials such as iron and molybdenum, can promote rice growth in a direct-seeding system. The optimal timing for application is before sprouting, and the amount applied affects the growth outcome. Double coating with Benmoly has a positive effect on rice growth.