13 March 2024, Bengaluru: Onion (Allium cepa L.) a significant commercial vegetable crop in India, is divided into three types: common onion, small common onion, and multiplier onion. Multiplier onions, 5-6 bulblets clumping, are cultivated in Tamil Nadu, Andhra Pradesh, South Karnataka, parts of Odisha, and Kerala. They are planted with stored multiplier onions for up to 6 months. Onion is planted with close spacing (15-20 cm) and requires 40-50 woman-days to plant one ha, as it requires 4.5 lakhs hills per ha to be planted.
The high labor requirement and higher wages for onion planting contribute to an 11.9% increase in production costs. Manual planting is cumbersome and time-consuming, making mechanization of onion bulblet planting a cost-effective solution that eliminates drudgery and ensures timely operation.
The tractor-operated raised bed former cum onion bulblet planter comprises a raised bed former, onion bulblet hopper, metering unit, ground wheel, and furrow opener. The bed former forms raised beds of 900 mm width and 200 mm height, while the onion bulb metering unit features an onion bulblet storage hopper and metering mechanism.
The onion bulblet planter uses a chain-cup-type seed metering device, a seedbox cum duct, a driving shaft powered by a ground wheel, a seed tube with a spout, and a seed cleaner. The bulblets are delivered into furrows through a seed tube, with hoe-type furrow openers fitted at the delivery end. The planter has four rows and can be tractor-mounted, with additional rows added as needed.
Onion bulbs are filled in the hopper and the tractor is operated at a forward speed of 1.5 km/h. The raised former forms a raised bed of 850-900 mm in width and 200 mm in height. The furrow opener makes furrows of 50 mm width and 50 mm depth. The seed metering system meters onion bulbs from the seed storage and delivers them to the seed tube. Further, the onion bulbs are dropped at the boot of the furrow opener and self-covered by soil. The field capacity of the machine is 0.12 ha/h. About 35% of input saving in terms of labor, time, and energy, also reduces the drudgery involved in onion bulb planting.
