Soil tillage is one of the most critical processes in the agricultural production system, requiring the greatest energy and time of any operation. The purpose of this study was to evaluate the performance of a tractor-drawn combined tillage implement. The performance of the implement was evaluated in terms of the draft force, draft power, wheel slip, fuel consumption, mean weight soil diameter, field efficiency, soil inversion, volume of soil tilted, and tillage performance index. The tillage implement is tested at forward speed of 3, 5, and 7 km/hr and depth of operation 10, 15, and 20 cm. The optimum performance was achieved at 20 cm depth and 5 km/h forward speed. Hence, a maximum tillage performance index of 1.202 was recorded with a minimum mean weight diameter of 12.73 mm while the draft, draft power, wheel slip, field efficiency, and fuel consumption were found to be 2289.71 N, 1.87 kW, 8.74%, 84.71%, and 6.16 l/hr, respectively. The analysis of variance (ANOVA) revealed that forward speed and depth of operation had significant effects on draft, draft power, wheel slip, mean weight diameter, field efficiency, tillage performance index, and fuel consumption at a (P<0.05) level of significance. The costs of operation of tractor-drawn combined tillage were 1707.43 Birr/hr whereas the break-even point, payback period, and benefit-cost ratio were 1,349.45 hr/yrs, 1.84 yrs, and 4.34, respectively. From the above results, it can be concluded that farmers could use this implement for tillage/seedbed preparation.
Woyessa et al. (Wed,) studied this question.