Mirko Simikić

The effects of working parameters and tillage quality on rotary tiller specific work requirement

Accepted 31 October, 2011 The aim of this paper was to analyze the influence of rotary tiller rotor rotation direction on specific work requirement (SWPTO). The SWPTO was calculated by measuring the power take-off (PTO) 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 SWPTO 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 SWPTO 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 R 2 (0.92 to 0.99 for conventional and 0.84 to 0.93 for reverse rotor rotation direction). Reverse rotor rotation direction had lower SWPTO 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.