Droplet class and spray volume influence on spray characteristics and herbicide performance in a maize-Brachiaria grass intercropping system

Abstract Optimizing maize–Brachiaria intercropping requires effective weed management with selective maize herbicides. This study evaluated the spray performance and efficacy of atrazine + nicosulfuron for weed management in maize–Brachiaria intercropping, focusing on how droplet classes and spray volumes affect maize growth and yield. The deposition experiment was conducted in a greenhouse in a completely randomized design with six replications. Field experiments were conducted during two seasons [2021 early season—ES (rainy season) and 2022 late season—LS (dry season) in a randomized block design and a 4 × 2 factorial (fine, medium, coarse, and very coarse droplet classes × spray volumes of 77 and 144 L ha −1 ) plus four controls treatments: Maize + Brachiaria without weed control, Maize + Brachiaria manually weeding, Brachiaria manually weeding, and Maize manually weeding. The study revealed that droplet class and spray volume significantly influence droplet deposition. Treatments spraying fine droplets at 144 L ha −1 exhibited higher coverage and droplet density levels. Intercropping maize with Brachiaria grass can be achieved without significant yield losses in the ES. However, the intercropping system reduced maize yield by approximately 17% in the LS. Applying the herbicides atrazine + nicosulfuron at 144 L ha −1 improved weed control and positively impacted maize yield during the LS.