Design and Development of a Tractor Drawn Automatic Onion Transplanter

A 15 hp mini tractor operated 4-row automatic onion transplanter was developed to transplant onion seedlings raised in hexagonal shaped (honeycomb) paper pot chain of length 800 mm, width 180 mm and depth 40 mm. A total of 128 seedlings were raised in this paper pot chain. The onion transplanter was developed to transplant 4rows of onion seedlings at a time with a spacing of 10 cm between each row. It consisted of a furrow opener, a covering device, conveying belt and cutting units, a seedling delivery tube for each of the four rows and two ridgers for making two ridgeseach of 40 cm wide at the top. Belt-type conveying unit was employed for the movement of the paper pots. On the conveyor, paper pot chain was put and it conveyed the same to the furrow opener through the seedling delivery tubes after singulation using two types of cutting units i.e. three rotary cutters and a vertical blade. The rotary cutters were used to tear the paper pot chain lengthwise along the rows whereas one vertical blade was used to cut the paper pot chain perpendicular to the rows so that seedlings were singulated and one seedling was available for each seedling delivery tube at a time. Rotary cutters were powered by ground drive wheel whereas vertical blade was powered by a 12V 600 W DC motor using the tractor battery. The developed automatic onion transplanter was tested in the field with alluvial soil (M. C. 20.3% db) at an average forward speed of 3.0 km/h. The average row to row spacing, plant to plant spacing and depth of placement were found to be 8.12 cm, 20.3 cm, and 2.99 cm, respectively. The average effective field capacity of the developed transplanter for transplanting onion seedlings was found to be 0.071 ha/h with a field efficiency of 71.25 % andaverage missing index and multiple index was found to be 33% and 18.77%, respectively. K e y w o r d s