Herbicide Combination Strategies for Enhanced Weed Management, Growth and Grain Yield of Maize (Zea Mays L.) and Associated Weeds.

Field experiments were carried out at the Faculty of Agriculture, Cairo University, during the 2022 and 2023 summer seasons, to assess the efficacy of newly formulated herbicides on weed management and their impact on maize growth, grain yield and yield components. The treatments were four pre-emergence herbicides: (S-metolachlor 31.25% + Terbuthylazine 18.75%), (Pendimethalin 33% + Clomazone 15%), (Pendimethalin 45.5%), and (S-metolachlor 96%) and two post-emergence herbicides: (Mesotrione 5% + Nicosulfuron 20%), and (Nicosulfuron 75%). Additionally, two nonchemical treatments (hoeing twice and a weedy check was the control treatment. The experimental design was the randomized complete block design with three replicates. The main findings reported that the highest weed count in samples taken at 45 days after sowing and harvest was in the weedy check treatment (174.5 p/m² and 189.33 p/m² . Among all the tested treatments, pre-emergence herbicide treatments were the most effective across all parameters (weed number, fresh weight, and dry weight) and crop traits. The best treatments were S-metolachlor 31.25% + Terbuthylazine 18.75%; Smetolachlor 96% and Pendimethalin 33%+ Clomazone 15% pre-emergence herbicides have a significant impact on maize yield and yield components. Grain yield per hectare exhibited strong positive correlations with shelling percentage (r = 0.85), number of grains (r = 0.789), and weight of ear grains (r = 0.756). Hoeing twice, S-metolachlor 96% and Pendimethalin 33%+ Clomazone 15% provides the highest yield; herbicide combinations provide more effective weed control. [ABSTRACT FROM AUTHOR]