Weed management efficacy of herbicides and allelochemicals in direct-seeded rice

A field experiment was conducted at Zonal Agricultural Research Station, Bangalore to quantify the effect of different herbicides and allelochemicals on weed density, weed biomass, yield and economics of direct-seeded rice. The post-emergence application (PoE) of bispyribac sodium 40 g/ha provided wide spectrum weed control with a weed control efficiency of 94.99% in 2020 and 95.01% in 2021, which was comparable to pre-emergence application (PE) of bensulfuron-methyl + pretilachlor 660 g/ha (93.24% in 2020 and 93.09% in 2021, respectively). The crop growth parameters and grain yield were highest with hand weeding at 20 and 40 days after seeding (DAS) (5.1 t/ha in 2020 and 5.2 t/ha in 2021) and it was at par with bispyribac-sodium 40 g/ha PoE (5.0 t/ha in 2020 and 5.0 t/ha in 2021) and bensulfuron-methyl + pretilachlor 660 g/ha PE (4.8 t/ha in 2020 and 4.9 t/ha in 2021). Among the allelopathic extracts tested, higher rice grain yield was recorded with Eucalyptus leaves extract (3.3 t/ha in 2020 and 3.7 t/ha in 2021). The highest B:C of 2.65 and 2.57 in 2020 and 2021, respectively was recorded with bispyribac-sodium 40 g/ha PoE.