Weed infestation of maize crops depending on elements of cultivation technology in the conditions of the Northern Steppe of Ukraine

Abstract

Goal. To develop approaches to improving the efficiency of the weed management system in maize by optimizing herbicide application, enhancing the phytocoenotic resilience of crops, and reducing the chemical load in agrocenoses. Methods. The research was conducted in a field experiment by the Plant Protection Laboratory of the Institute of Grain Crops of the NAAS of Ukraine at the State Enterprise Experimental Farm «Dnipro» (northern subzone of the Steppe of Ukraine). Maize cultivation practices followed generally accepted recommendations, with winter wheat as the preceding crop. The three-factor experimental design included soil-applied herbicides (factor A), increased fertilizer rates (factor B), and methods of post-emergence herbicide application (factor C). Results. Soil-applied herbicides were the main factor controlling weed infestation in maize crops, reducing the initial weed density by 10—26 times (to 1.4—3.3 plants/m²) and maintaining a consistently low level of weed infestation throughout the growing season. Mineral fertilizers had a biphasic effect: at the early stages, N₆₀P₆₀K₆₀ reduced weed density by 3—25%, whereas in the second half of the growing season, it contributed to an increase in weed density by 18—140%, particularly in the absence of chemical protection. Band application of post-emergence herbicides provided an additional 5—22% reduction in weed infestation compared with broadcast application. The highest average maize grain yield (7.50 t/ ha) was obtained with the combination of the increased N₆₀P₆₀K₆₀ fertilizer rate, a soil-applied herbicide, and band application of post-emergence herbicides, exceeding the other treatments by 0.38—1.25 t/ ha. Conclusions. Under the conditions of the Northern Steppe of Ukraine, the combination of intensive mineral nutrition with the mandatory application of soil-applied herbicides is crucial for increasing maize productivity. Band application of post-emergence herbicides is an effective component of optimizing the weed management system and provides a stable additional increase in grain yield.