The Effect of Travel Speed and the Position of Rotary Tiller Hood on Soil Surface Roughness

Availability of efficient attachments on tillage implements is one of the challenges in variable-rate tilling concept. Reposition of the rotary tiller’s soil hood automatically makes it a practical tool for variable rate plowing. In this study, an electro-hydraulic system using a closed-loop control circuitry and the tractor hydraulic power was utilized to create different roughness by soil hood reposition. The effect of travel speed and soil hood position in creating random roughness (RR) of the resulting soil surface was investigated using a completely randomized design and a 3×4 factorial experiment in 3 replications. The average RR created by the travel speeds of 2.6, 3.5, and 4.8 km/h were 1.32, 1.91, and 2.61 cm, respectively. Similarly, the average of RR created using three soil hood positions of 0, 40, and 80 degrees were 1.43, 1.94, and 2.46 cm, respectively. The analysis of variance showed that the effects of travel speed and soil hood position on random roughness index were significant at the probability level of 1%. Therefore, it can be stated that in the case of real-time control of these two factors and using the RR index as a control feedback signal, a rotary tiller can be implemented to perform variable rate tilling.