Effect of velocity ratio of rotavator on Tillage Performance Index (TPI) in sandy clay loam soil

Efficient tillage operations are fundamental for enhancing soil productivity while minimizing energy consumption and input costs. Among mechanized tillage implements, the rotavator is widely used for seedbed preparation due to its soil pulverizing capabilities.The velocity ratio of the rotavator defined as the ratio of rotor peripheral speed to the forward speed of the tractor plays a pivotal role in determining tillage effectiveness. This study investigates the effect of velocity ratio on the Tillage Performance Index (TPI) insandy clay loam soil, aiming to optimize operational parameters for improved energy efficiency and soil management. Field experiments were conducted at the Research Farm of the Department of Agricultural and Food Engineering, IIT Kharagpur, India. Two different field conditions were considered: Field FA (with wheat stubble) and Field FB (ploughed land without stubble). Tillage operations were performed using a rotavator at three different depths (80 mm, 100 mm, and 120 mm) and under various gear and throttle combinations. The actual forward speed, soil cone index, and fuel consumption were recorded using precise instrumentation including an inductive proximity sensor and a cone penetrometer. TPI was calculated using volumetric soil displacement, cone indexreduction, and fuel energy consumption. Results indicated that the highest TPI values were achieved at L2 gear settings (velocity ratio between 5 and 7), where a balance between soil pulverization and fuel efficiency was observed. Field FB consistently recorded higher TPI values than Field FA, attributed to lower cone index and reduced wheel slip. Additionally, TPI increased with tillage depth due to the higher volume of soil handled, while optimal throttle settings were found to enhance performance up to a point, beyond which increased fuel consumption reduced TPI. These findings underline the importance of selecting appropriate velocity ratios and throttle settings to maximize tillage efficiency. The outcomes have practical implications for rotavator design, operator training, and sustainable soil management practices in similar agro-climatic zones.