Weed dynamics, crop growth and yield as affected by different weed management practices and plant growth-promoting rhizobacteria in direct-seeded upland rice

Abstract

Effect of different weed management practices and plant growth-promoting rhizobacteria (PGPR) were evaluated in Jorhat (Assam) on weed dynamics, crop growth and yield in direct-seeded upland rice during 2018 and 2019. Results revealed that density and dry weight of weeds were the lowest with Pseudomonas fluorescens among PGPR treatments. The growth and yield attributing characters were significantly improved due to P fluorescens contributing to the highest grain and straw yield of rice. Single application of pretilachlor pre-emergence 0.75 kg/ha or application of pretilachlor pre-emergence 0.75 kg/ha followed by one hand weeding at 30 DAS resulted in least density and dry weight of weeds at initial stages of crop growth. The lowest values were recorded in three hand weedings done at 15, 30 and 45 DAS. Better growth and yield attributing characters of rice with three hand weedings at 15, 30 and 45 DAS resulted in the highest grain and straw yields. Combination of P fluorescens with either three hand weedings at 15, 30 and 45 DAS or pretilachlor pre-emergence 0.75 kg/ha followed by one hand weeding at 30 DAS was found to be superior with grain and straw yields along with similar trend in gross and net returns. However, the benefit: cost ratio was the highest in the combination of P fluorescens with pretilachlor pre-emergence at 0.75 kg/ha followed by one hand weeding at 30 DAS.