PhD

The tractor drawn root harvester was designed and developed by considering soil, crop and machine parameters and performance evaluation of the machine was carried out in the experimental area at KCAET, Tavanur and different farmers’ fields at Palakkad and Thrissur districts. The developed machine mainly consists of main frame, power transmission system, digging and soil separator units. The effect of three blade geometries viz., straight edge, V-type and crescent blades at three rake angles of 15, 20 and 25 deg. and at three forward speeds of 1.5, 2.0 and 2.5 km h-1 for the digging unit of the harvester were evaluated in terms of draft, digging efficiency, per cent damage of tuber/rhizome and fuel consumption of tractor mounted harvester for harvesting coleus, ginger and turmeric. The best optimal condition was observed at a forward speed of 2.0 km h-1 with 20 deg. rake angle for V-type blade. The soil separator unit of the harvester was evaluated along the digging operation. The soil separator unit was tested with different operational parameters viz., diameter of crank 40, 60 and 80 mm and spring tension 800, 1200 and 1600 N m-1. The best optimal operational conditions were observed at a spring tension of 1600 N m-1 with 80 mm diameter of crank. The maximum draft of 2009.52 N was recorded in straight blade while the minimum of 1418.66 N was observed in V-type blade. The maximum digging efficiency of 99.89 per cent was noticed in V-type blade, whereas the lowest of 84.15 per cent in straight edge blade. The least damage coleus of 0.59 per cent was observed in V-type blade whereas highest of 5.5 per cent was obtained in crescent blade. Among the different type of blades tested, the less fuel consumption of 3.80 l h-1 was noticed for V-type blade, whereas the maximum of 4.98 l h-1 for straight edge blade. In the case of harvesting ginger, the maximum draft of 2176.33 N was recorded in straight edge blade while the minimum of 1374.31 N was observed in V- type blade. The maximum digging efficiency of 99.57 per cent was noticed in V-type blade, whereas the lowest of 80.40 per cent in straight edge blade. The least damage coleus of 0.86 per cent was observed in V-type blade whereas highest of 6.05 per cent was obtained in crescent blade. Among the different type of blades, the less fuel consumption of 3.74 l h-1 was noticed for V-type blade, whereas the maximum of 5.19 l h-1 for straight edge blade. In the case of harvesting of turmeric, the maximum draft
of 2192.08 N was recorded in straight edge blade while the minimum of 1390.06 N was observed in V-type blade. The maximum digging efficiency of 99.50 per cent was noticed in V-type blade, whereas the lowest of 81.91 per cent was recorded with the straight edge blade. The least per cent damage coleus of 0.74 per cent was observed in V-type blade whereas highest of 7.3 per cent was obtained in crescent blade. Among the different type of blades, the less fuel consumption of 4.0 l h-1 was noticed for V- type blade, whereas the maximum of 5.57 l h-1 for straight edge blade. The field capacity of the machine for coleus, ginger and turmeric were 0.15, 0.16 and 0.16 ha h-1 respectively and the field efficiencies were 86.11, 88.89 and 88.89 per cent respectively. The soil separation indices of root crop harvester for coleus, ginger and turmeric were found out as 82.71, 73.22 and 68.82 per cent respectively where as the conveying efficiencies were 90.70, 87.55 and 89.71 per cent respectively. The estimated cost of the prototype tractor drawn root crop harvester was as Rs. 60,000. The cost of operation was found out as Rs. 767.57 per hour. The saving in cost over root crop harvester for three root crops was 89 per cent. The machine has BEP of 40 h, PBP as 1.5 years and BCR as 10.7.