THE IMPACT OF SYSTEMATIC HERBICIDE APPLICATION ON MAIZE GRAIN YIELD

Abstract

Modern agriculture focuses on the adaptive utilization of resources and the implementation of innovative agro-technologies, particularly the efficient use of herbicides in maize grain crops. The relevance of this study is determined by the low competitiveness of maize in weed-infested agrocenoses, leading to significant yield losses. The aim of the study was to evaluate the effectiveness of herbicides and their combinations in reducing weed infestation in maize crops in the steppe zone of Ukraine. During 2019–2021, a two-factor field experiment was conducted on chernozem soils in the steppe zone. Factor A involved the application of glyphosate (2000 g/ha) in the form of potassium salt, while Factor B comprised post-emergence herbicides such as nicosulfuron (50 g/ha) and its combinations with thifensulfuron-methyl (10 g/ha), dicamba (150 g/ha), 2,4-D (450 g/ha), and florasulam (5 g/ha). Weed infestation was assessed at various stages of maize vegetation. The results demonstrated that herbicide applications reduced the density of perennial weeds by 60–75% and annual weeds by 15–18%. The most effective combinations included nicosulfuron (40 g/ha) with 2,4-D and florasulam, which decreased the density of annual weeds by 91%. Before harvest, in the variant with a total herbicide application, the weed density was significantly lower (9.9 plants/m² for annuals and 0.9 plants/m² for perennials) compared to the control (119.1 plants/m² and 19.7 plants/m², respectively). The conclusions highlight that the use of adaptive soil tillage systems and herbicides significantly improves the phytosanitary condition of maize crops, reduces energy expenditures, and restores soil fertility. The obtained results provide a scientific basis for optimizing herbicide protection of maize under the conditions of the steppe zone of Ukraine.