It is required to employ variable rate (VR) tillage because the soil is not uniform and immense spatial variability is available inside the agricultural fields. A conventional rotary tiller was instrumented to instantly vary the tillage intensity based on the tilled soil surface roughness measurement. The random roughness (RR) was estimated as the standard deviation of surface peaks and depressions which were measured using an infrared sensor. The tilling intensity was adjusted based on rising off and lowering down the tiller soil shield that was controlled by a hydraulic actuator. The soil shield could be adjusted from 0 to 80° in 20° increments with an average response time of 0.26 s. The field tests were performed in order to recognize whether the VR tiller can create predefined soil roughness which was assigned in three ranges of 0.5≤RR1≤1.5, 1.5
