Speed and Depth Effects on Soil Fragmentation, Non-Chemical Weed Control, and Immediate Crop Damage During Mechanical Weeding in Wide-Row Wheat

Mechanical weed control is a crucial sustainable alternative to chemical herbicides, yet optimising implement parameters to balance non-chemical weed suppression with crop safety remains challenging. This study evaluated how forward speed and working depth influence soil fragmentation, weed control efficacy, and immediate plant injury during the mechanical weeding of wide-row wheat. Field experiments tested three tractor speeds (6, 9, and 12 km·h−1) and two working depths of duckfoot sweeps (30 and 50 mm). Key indicators—including the degree of soil crumbling, mean clod diameter, weed control effectiveness, and crop injury rates—were evaluated using analysis of variance. Higher speeds increased soil crumbling and reduced clod size, whereas effective weed destruction depended primarily on depth. Working with duckfoots at 50 mm achieved 95.9% weed removal efficiency, outperforming the 30 mm depth (80.2%). However, increasing speed above 9 km·h−1 caused a sharp rise in the immediate crop injury rate (reaching 26.8%), while direct plant cutting remained low. This indicator represents visible post-treatment injury and should not be interpreted as irreversible crop loss or yield reduction. These findings demonstrate an asymmetric impact of operating parameters: deeper depths maximise weed clearance, but excessively high speeds severely increase crop damage. Optimising these settings is vital for sustainable field operations and underscores the need for improved implement designs to minimise lateral soil discharge.