Comparison of different inoculation methods and carrier materials for allelopathic Pseudomonas strains in weed management of direct-seeded rice

The use of allelopathic bacteria to combat weed infestation in crops is regarded as an effective technology for sustainable agriculture and environment. In this regard, six bacterial strains from the genus Pseudomonas were selected for their ability to inhibit the germination and growth of Leptochloa chinensis (L.) and Dactyloctenium aegyptium (L.) while promoting the growth of rice. These strains were applied to the target weeds and rice using different application methods viz. seed priming, liquid application, and foliar application. The results showed that all strains possessed herbicidal activity and significantly reduced growth of L. chinensis. Shoot length, root length, and fresh biomass of D. aegyptium were also significantly reduced in all strains by 60, 55, and 76%, respectively, with the exception of R15-4. Additionally, the growth suppression of both weed species was more prominent in the liquid application. The selected allelopathic strains also demonstrated plant growth-promoting traits and improved the growth and physiological parameters of rice in all three application methods, with the best results achieved with liquid and foliar applications. The survival efficiency of the bacterial strains was also tested using four different carrier materials, where the press mud was found the best carrier for controlling L. chinensis and D. aegyptium.