Evaluating finger weeder angle, spacing, and speed in field and soil bin experiments

Abstract Finger weeders were first developed in the 1950s and have since been widely adopted by farmers to improve physical weed control (PWC) within crop rows. Research on finger weeders has largely been comparative, with most studies identifying a top-performing weed control practice among various physical or chemical treatments. Weeding tool performance, however, is often highly variable, affected by tool design and adjustment, soil conditions, and both weed and crop species and size. Finger weeder operating settings have not been systematically tested to determine whether they could optimize tool performance. In this project, field and soil bin experiments examined the effects of finger weeder angle, spacing, and speed on weed control efficacy and weed/crop selectivity. Three finger weeder angles were tested: 108°, which removed soil near the crop; 90°, typical for most commercial tools; and 68°, which moved soil into the crop row. Three spacings and speeds were compared: fingers overlapping (−0.6 cm), touching (0 cm), or spaced apart (2.5 cm); and 4, 7, and 9 km h −1 . In both the field and soil bin, finger weeders set at a 68° angle resulted in the greatest efficacy. Decreasing finger spacing and increasing speed improved efficacy in soil bin experiments, as expected, but spacing and speed effects were not detected in the field. The experimental soil bin system shows promise for PWC testing, possibly offering insights that could not be detected in more variable field conditions.