Efficacy of pre- and post-emergence herbicides on weed dynamics, grain yield and economics of spring maize

Weed infestations are a serious threat to the maize as competition for light, water and nutrients drastically reduces the yield, demanding an immediate and effective solution. In this context, two years of field trials were executed in spring 2024 and spring 2025. Treatments were included: no weeding; manual weeding (15 and 30 days after sowing); atrazine + s-metolachlor (pre-emergence, post-emergence and both); atrazine + mesotrione (pre-emergence, post-emergence and both); and atrazine + s-metolachlor (pre-emergence) followed by atrazine + mesotrione (post-emergence). The outcome of the study depicted that hand weeding decreased the weed density by 93% in comparison to no-weeding control plots which ultimately depicted an increment of 51% in number of grains per cob, 57% in thousand-grain weight, and 79% in grain yield, as well as a 32% increment in harvest index as compared with the no-weeding control. Among the various herbicides, the sequential application of atrazine + s-metolachlor as pre-emergence followed by atrazine + mesotrione as post-emergence lowered the weed density by 83% which eventually showed an increment of 48% in number of grains per cob, 51% in thousand-grain weight, 76% in grain yield, and 28% in harvest index compared with the no-weeding control. The manual weeding in large-scale cultivation is very laborious, so the sequential application of pre-emergence followed by post-emergence herbicides can effectively control the weeds in large-scale maize cultivation and maximize the maize yield.