Interactive effects of planting dates and herbicide treatments on weed suppression and grain yield of maize (Zea mays L.)

Maize is a staple crop of global importance, ranking first in cultivated area and third in total production worldwide. Its growth and productivity are influenced by numerous factors, among which weed competition and shifts in planting dates due to climate change pose significant challenges to farmers. Therefore, this study was conducted to evaluate the effects of several modern chemical herbicides (Apple at 1 L ha⁻¹, Arrivo at 1.5 L ha⁻¹, and Ramses at 50 g ha⁻¹) on the growth and yield of maize (Zea mays L.), cultivar Drachma, sown at different spring planting dates (17 March, 26 March, and 5 April 2025). The experiment was arranged in a randomized complete block design with three replications. Herbicides were applied at the recommended rates 21 days after sowing, when the plants reached the 4-6 leaf stage. The results indicated that most of the herbicides significantly improved the studied traits. The herbicide Abel resulted in the lowest weed density (8.04 plants m⁻²), the highest weed control efficiency (88.10%), and the greatest number of grains per row (34.24). Ramses produced the highest 500-grain weight (146.30 g). The first planting date (17 March 2025) recorded the tallest plants (185.81 cm), the largest leaf area (620.47 cm²), and the highest grain yield (14.24 t ha⁻¹). Overall, the combined use of the earlier planting dates (17 and 26 March 2025) with the herbicides Abel and Ramses produced the most favorable results, enhancing vegetative growth and significantly increasing final grain yield.