The onion (Alilum cepa L.) is one of the important commercial vegetable crops grown on a large area in India for local consumption as well as for export purpose. The area of onion is 0.7 million ha with a production of 91.33 MT. Onion growers are facing lot of problems in transplanting of onion seedlings with the shortage of farm labourers during transplanting season. Therefore, efforts were made to develop a tractor operated semi-automatic onion transplanter at MPKV Rahuri. Physical properties like height, weight, diameter, moisture content and compressive strength etc were determined for 6, 7, and 8 week age of onion seedlings. Two metering mechanisms i.e. Finger type and Plug type were studied in laboratory with three different travel speeds of 0.75 km/h, 1.00 km/h and 1.25 km/h for different age group of onion seedlings. It was observed that plug type metering mechanism at speed of 0.75 km/h travel speed with 7 week age seedling were found more suitable for transplanting. The field trials of semi-automatic transplanter revealed that with the plug type metering mechanism the row to row spacing of 20–22 cm, plant to plant spacing of 10.5–22 cm and depth of placement was observed as 3.5 to 4 cm. The missing percentage was 10–12. The field capacity of the machine was 0.09 ha/h with field efficiency of 68–75 per cent. The draft of machine was in the range of 466–476 kgf. The saving in cost of operation over manual transplanting was 38.84 per cent.
Onion, Transplanter, vegetable
