Optimization of the Adjustment of a Vertical Axis Rotary Brush Weeder for Intra-Row Weed Control in Row Crops

Abstract

Abstract Mechanical intra-row (within the row) weeding is important in non-herbicidal growing systems as it reduces time-consuming hand-weeding. Brush weeding, with brushes placed on a vertical rotating axis is a new method of intra-row weeding. It can be operated in two different ways determined by the direction of brush rotation. The one is primarilyuprootingthe weeds, while the other one is mainlycoveringthem with soil. In this study, the optimal adjustment of this weeder was studied in two field experiments both sown with onions in rows. Both the intra-row weeding effect and the effect on crop yield were measured. Results showed that peripheral speed of the brushes and tractor speed had no clear effect on the weeding performance for either working principles (uprootingorcovering). However, narrowing the distance be- tween the brushes to 30 mm foruprootingincreased the level of intra-row weed control without negative yield responses. Forcovering, the working depth of the brushes had the most influence on the selectivity (the ability to suppress weeds as opposed to crop plants), because it affected the percentage of soil cover on the crop and weeds. The selectivity ofcoveringincreased when the difference in size between weed and crop plants increased, that is, the best weed control was obtained when operating against small weed plants growing in a large crop.