Performance evaluation of wide cutting tillage tools of different geometry for dryland farming

Abstract The ‘Bakhar’ blade is a very popular bullock-drawn implement in Indian dryland farming, used for primary and secondary tillage operation. The performance of this existing tool was evaluated with respect to other tools of different geometry such as straight, convex, concave, triangular and V-shaped in a lateritic sandy loam soil of Kharagpur under uniform soil conditions. These tools were operated at 4 different rake angles, i.e. 25, 40, 55 and 70°, and 2 soil working depths of 2.5 and 7.5 cm. The observations recorded were specific draught, mean weight diameter of soil aggregates, inverse performance index and specific vertical force. On comparing the overall performance of different tools at 2.5 and 7.5 cm working depths, it was found that the convex tool at the rake angle of 55° indicated minimum specific draught 2.0 N cm −2 and 1.76 N cm −2 , mean weight diameter of soil aggregates 7.37 mm and 7.82 mm with minimum inverse performance indices of 14.78 and 13.80, which is 13–88 and 12–114% lower than that indicated by other tools at different rake angles.