Development and Field Evaluation of a Variable-Depth Tillage Tool Based on a Horizontal Pneumatic Sensor Measurement

Soil compaction can be naturally occurred or can be machinery-induced. Subsoiling is often applied to loosen soil compaction and decrease soil strength to levels that allow for root development and growth. Variable-depth subsoiling which modifies the physical properties of soil only where the tillage is required for crop growth has the potential to reduce labor, costs and fuel, and energy requirements. Since this study aimed to perform subsoiling operations with variable depth, the variable-depth tillage (VDT) tool was developed. A pneumatic multi-nozzles sensor has been used to simultaneously predict the depth of a soil layer in three depths (15, 30, and 45 cm), and send a signal to control the depth of the VDT tool. Evaluation of the VDT tool system was performed by two methods namely static and dynamic tests. In static evaluation, the system response time was measured to reach 95% of the proposed depths. The dynamic evaluation of the tool was accomplished in two steps in the field. The amount of fuel consumption and the travel distance of the tool tine to reach the desired operation depth were measured and compared with the common subsoiler (when the depth control was OFF). The average fuel consumption by using the variable-depth tillage tool decreased by 17.36% compared to the constant depth. Furthermore, the pneumatic sensor tine penetrated into the soil perfectly and sent the control signal to the control unit of the VDT tool in real-time, and the VDT tool loosened the soil at the exact depths sent by the sensor.