About 55-60 per cent of onion comes from Rabi season and 40-45 per cent from Kharif and late Kharif season. Generally farmers sow onions in nursery in flat beds raised on the fields.
But during khariff a sudden rainfall washes away the raised mud beds and affects the crops. For successfull Kharif onion production, the National Horticultural Research and Development Foundation (NHRDF), Nashik developed a technique.Well ploughed
The field is ploughed well and nursery beds made. The nursery bed should be raised 15–20 cm height from the ground level with width 0.80-1.0 meters. The length can be kept as per convenience.
Distance between two beds should be about 60 and 75 cm. Surface of beds should be smooth and well levelled. About 15-20 gm of single super phosphate (SSP) must be applied at the time of bed preparation for each bed.
The beds should be irrigated for 15-20 days, before sowing and covered with 250 gauge transparent polythene for soil solarisation.
Application of Trichoderma viride fungal culture at 5 kg/ha is recommended to manage damping off and raising healthy seedlings. The Trichoderma viride should be mixed in 25 times decomposed well sieved farmyard manure for application.
Seed bulbs should be treated with thiram at rate of 2 gm/kg of seed. Sowing of seeds should be done in lines at a proper spacing 5-7 cm row-to-row.
For one metre square area 5-7 gm of seeds would suffice. For planting in one hectare 7-8 kg seeds are required.
Seeds after sowing should be covered with fine powdered compost followed by light watering.
The beds should be covered with dry straw or grass or sugarcane leaves to maintain required temperature and moisture.Irrigation
Watering should be done till germination. Mulching materials should be removed immediately after germination is completed.
The seedlings become ready for transplanting after 6-7 weeks. Ideal time for sowing in Kharif is February-April in South, May-June in Maharashtra and other parts of the country.
(R. K. Singh is Assistant Director, email: email@example.com, mobile: 09881303443 and R P Gupta is presently the Director, NHRDF , Nashik, 422 003, Maharashtra.)