Transplanting of paddy is a labour intensive operation, requiring about 300–350 man-h/ha, which is roughly 25 per cent of the total labour requirement for the crop. Transplanted paddy require low seed rate (50 kg/ha) as compared to other methods like drilling (100 kg/ha) and broadcasting (130 kg/ha). Four-bar linkage mechanism of a power tiller operated 8-row rice transplanter was analyzed and accordingly modified. The maximum acceleration and velocity at modified link lengths were found to be 1928.40 cm/s2 and 140.10 cm/s respectively at 125 rev/min crank speed. Total distance travelled by the finger in the vertical direction was found to be 20.05 cm. A manually operated new model of 2 - row rice transplanter was developed using the modified four-bar linkages and tested in the puddled field. The average hill-to-hill spacing, depth of planting, no. of seedlings per hill, height of seedlings, missing hills and visible damage were found to be 21.68 cm, 6.98 cm, 3.68, 20.21 cm, 0.085 and 0.27 respectively. The missing hills and floating hills were found to be 8.54 per cent and 3.66 per cent respectively. The actual field capacity and the efficiency of the developed rice transplanter were found to be 0.14 ha/day (8 hrs) and 85.5% respectively.
Four-bar linkage, Kinematic analysis, Paddy transplanting, Field capacity
