Effects of Mechanical Weed Control and Manual Hoeing on Weed Infestation and Maize Grain Yield: A Three-Year Field Experiment

This study evaluated the effects of different mechanical weed control systems on weed biomass, weed flora composition and maize grain yield during a three-year field experiment conducted from 2021 to 2023 in the Zagreb area, Croatia, using a randomized complete block design with three replications. The following three weed control treatments were compared. T1—mechanical weed control between the crop rows with a motor cultivator combined with manual hoeing within the crop rows. T2—mechanical weed control between the crop rows with a motor cultivator without weed control within the crop rows. T3—without any weed control as control. The weed control system had a statistically significant effect (p < 0.001) on weed biomass and maize grain yield throughout the study. The lowest average weed biomass and the highest average grain yield were recorded in T1, whereas the untreated control (T3) had the highest weed biomass and the lowest grain yield. Regression analysis indicated a strong negative association between weed biomass and maize grain yield (R2 = 0.833), demonstrating that higher weed biomass was associated with lower grain yield. During the three-year experiment, 14 weed species were recorded, with Amaranthus retroflexus, Ambrosia artemisiifolia, Sorghum halepense and Chenopodium album being the dominant species. The results indicate that combining mechanical weed control between the crop rows with manual hoeing within the crop rows was the most effective weed control strategy under the conditions of this study.