Soil disturbance and cutting forces of four different sweeps for mechanical weeding

- Four different sweeps for mechanical weeding were tested.
- Soil disturbance characteristics, cutting forces, and weeding rates were measured.
- All sweeps had similar draft force requirements.
- The ¾-conventional and Fin sweeps resulted in higher weed kill.

Sweeps are the most common tools for mechanical weeding for row-crops. However, how their soil disturbance characteristics are associated with the weeding performance has not been well documented in the literature. The main objective of this study was to evaluate the weeding performance of selected inter-row sweeps through laboratory tests. Four different sweeps, namely: Fin, Conventional, ¾-conventional, and Narrow-wing, were tested in an indoor soil bin at a working depth of 40 mm and a travel speed of 8 km h−1 in a sandy loam soil. Soil disturbance characteristics (uprooting and cutting width, burial width, and burial depth), soil cutting forces (draft and vertical), and weeding rates were measured. Based on the ANOVA outputs, all these variables were significantly affected by the treatments at p < 0.05, except for the draft force. The ¾-conventional and Conventional sweeps had higher vertical forces than the other sweeps. The Conventional and ¾-conventional sweeps produced an uprooting and cutting width of approximately 260 mm, and the Fin and Narrow-wing sweeps resulted in an approximately 7.2% larger uprooting and cutting width. The Fin sweep had the smallest burial width (zero), while the ¾-conventional sweep had the largest burial width (308 mm). This trend was also observed for the burial depth. In general, the burial depth decreased exponentially from the centre of the sweep path over the lateral distance. The Fin and ¾-conventional sweeps had over 70% weed kill and these two sweeps are recommended as the best choices for row-crop weed control.