The selected agrotechnical factors affecting the occurrence of black grass Alopecurus myosuroides in winter wheat crops in north-western Poland

Alopecurus myosuroides of the family Poaceae is a highly competitive species for winter cereal crops, particularly for barley and wheat, less frequently for root vegetables or rapeseed. This study aimed to determine the predominant factor or group of factors affecting the cover of A. myosuroides in winter wheat field depending on the tillage systems, time, and amounts of herbicides used. The following variables differentiating the quantitative contribution of A. myosuroides in the analyzed fields were assumed: plough or no-plough tillage, date of biocidal application, and the total amount of herbicides (active substances) used. When spring-only herbicide was applied, the lowest A. myosuroides cover, not exceeding 25%, was observed in the margins of winter wheat fields. The coverage of A. myosuroides, reaching 25–100% of the winter wheat area, regardless of the tillage system, was found when the herbicides from the group of sulfonylurea derivatives (acetolactate synthase ALS inhibitors) were frequently used. Winter wheat infestation with A. myosuroides was significantly lower when ploughing was applied. The highest cover of A. myosuroides, reaching 50–100% of the area, was observed only in the central part of the analyzed winter wheat fields, following the application of herbicides in autumn and spring or in autumn only.