Abstract

The aim of this paper was to analyze the influence of rotary tiller rotor rotation direction on specific work requirement (SW_PTO). The SW_PTO was calculated by measuring the PTO (power take-off) torque, PTO speed, working speed and depth, as well as the working width. The tillage quality was determined by the bulk density and soil structure. Reverse rotor rotation direction concept is characterized by more efficient tillage which provides significantly higher amount of macro-structure aggregates (0.25 to 10 mm) and their better distribution in the soil. Significantly lower SW_PTO was observed with the reverse rotor rotation direction. It was within the range of -2.15-27.74% (14.35% on average) depending on the work speed which was 0.29 to 1.08 m s^-1. Multiple linear regression provided new equations for the calculation of SW_PTO depending not only on the working parameters, but on the intensity of soil breaking and soil conditions as well. The obtained equations had high values of Coefficients of determination R² (0.92 to 0.99 for conventional and 0.84 to 0.93 for reverse rotor rotation direction). Reverse rotor rotation direction had lower SW_PTO values which were 20.3 and 15.5% for the working speeds of 0.5 and 1.0 m s^-1, respectively, and were obtained for equal values of tillage intensity parameters.

Key words: Tillage, rotary tiller, specific work, bulk density, soil structure.