<b>Specific Torque Requirement of Different Tractor PTO Operated Active Tillage Machinery</b>

The study aims to evaluate and compare the specific Power Take-Off (PTO) torque requirement of four active tillage implements - rotavator, double rotor rotavator, PTO-driven disc tiller, and power harrow under varying forward speeds and tillage depths. The findings intend to assist in optimal tractor-implement matching, enhance energy efficiency, and inform design improvements in tillage machinery. Field experiments were conducted on sandy loam soil using a New Holland 4010 tractor at three speeds (2.2, 3.6, and 4.8 km h-1) and depths (80, 100, and 120 mm). PTO torque was measured using a torque and power monitoring system. The experiment was laid out in a split-plot design with three replications. Statistical analysis was conducted, and regression models were developed using non-linear least squares optimization. Results revealed that specific PTO torque requirement significantly increased with both forward speed and tillage depth (p < 0.01). Among the implements, the rotavator exhibited the lowest average specific torque requirement (133.9 N-m m-1), while the power harrow and PTO-driven disc tiller showed the highest (168.9 and 164.8 N-m m-1, respectively) average specific torque requirement. Regression models indicated a quadratic relationship between forward speed and torque and a linear relationship with depth. The developed models exhibited high predictive accuracy, with R² ranging from 0.86 to 0.91 across the four implements. The torque requirement of active tillage implements is significantly influenced by implement type, forward speed, and tillage depth. These findings highlight the importance of selecting appropriate implements, and operating parameters to optimize energy use and reduce mechanical stresses on tractors. The developed regression models offer practical utility for estimating specific torque requirements under varying field conditions.