Evaluation of herbicide efficacy on weed dynamics and yield of maize in maize-sunflower cropping system

A field experiment was conducted for two consecutive years during the kharif seasons of 2018 and 2019 at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu. The field trial comprised ten treatments: pre-emergence (PE) application of atrazine followed by hand weeding, atrazine as PE followed by power weeding, PE atrazine + pendimethalin as a tank mix, PE atrazine + pendimethalin as a tank mix followed by hand weeding, topramezone as early post-emergence (EPOE), PE atrazine followed by EPOE topramezone, EPOE tembotrione, PE atrazine followed by EPOE tembotrione, control, and two hand weedings (weed-free). The PE atrazine followed by topramezone as EPOE significantly reduced the weed index (1.9) and increased weed control efficiency (85.7% and 75.9% at 60 and 90 DAS, respectively). This treatment also resulted in a higher maize grain yield of 8237 kg ha^-1, which was statistically comparable to the weed-free plot (8398 kg ha^-1) compared to other treatments. Consequently, it can be inferred that atrazine as a pre-emergence herbicide, followed by topramezone as an early post-emergence herbicide application, proved to be a highly effective approach for controlling weeds in maize crop.