Optimization of Machine Tractor Outfit: - Case of Disc Plough

Abstract Agricultural mechanization in Ethiopia is found to be at minimum level mainly depending on draft animals and human drudgery. One of the factors affecting on tractor matching to a proper disc ploughs in different climate and soil conditions. The objective of this study was to optimize machine tractor outfit for some selected agricultural tractor with disc plough. Therefore, three models of disc plough with tractors 80 hp and 50hp on the 2nd and 3rd gears forward speeds of 1.18 m/s, 2.01m/s, 0.89 m/s, and 1.18m/s respectively was tested and ploughed in vertisol and sandy clay loam soil type. The results obtained during ploughing operation in vertisol soil type 80 hp with 4 bottom disc plough 66 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.35 ha/hr, 17000N and 28 lit/ha respectively and 80 hp with 3 bottom disc plough 66 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.52 ha/hr, 13500N and 21.8 lit/ha respectively. Sandy clay loam soil 80 hp with 4 bottom disc plough 66 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.62 ha/hr, 11500N and 20 lit/ha respectively and 80 hp with 3 bottom disc plough 66 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.52 ha/hr, 8500N and 23.08 lit/ha respectively. Sandy clay loam soil 50 hp with 3 bottom disc plough 66 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.31 ha/hr 8500N and 19.2 lit/ha respectively and 50 hp with 4 bottom disc plough 50 cm disc diameter the field capacity, average pull force and average fuel consumption was 0.26 ha/hr, 7500N and 15.39 lit/ha respectively. Based on the performance evaluation results in vertisol soil type 80 hp tractor with 3 bottom disc plough 66 cm disc diameter and in sandy clay loam soil type 80 hp tractor with 4 bottom disc plough 66 cm disc diameter, 50 hp tractor with 3 bottom disc plough 66 cm disc diameter was the most appropriate for ploughing as it recorded the highest field capacity, low pull force and fuel consumption.