Crop production

Cultural Practices

Seed rate: A seed rate of 20-25 kg and 8-10 kg per hectare is required for the broadcasting and drill sowing, respectively.
Sowing: Planting can be done in three methods: •Transplanting • Broadcasting or drill sowing • Planting bulbs
Nursery management: Prepare 25 raised seed beds of 750cm (25ft) long, 4ft (120cm wide and 10-15cm (4-6 inches) high to raise seedlings sufficient for one hectare (10 beds for one acre). Apply 3-5 baskets farmyard manure and 1/2kg 15:15:15 NPK mixture to each bed and mix them well in the soil. Sow the seed thinly in 5 to 7.5cm (3 inches) rows. Irrigate the beds immediately after sowing. Seedlings will be ready for transplanting in about 6-8 weeks.
Transplanting: In well-ploughed land, prepare plots of 200x150cm and apply 50%N and the entire P205 and K20 before transplanting. Transplant seedlings in 15cm (6 inches) rows (1.5 to 10cm (3 to 4 inches), apart between the seedlings. Top-dress the crop with the remaining 50% N, 6 weeks after transplanting.
Broadcasting or drill sowing: This method is in practice in Northern Districts of Karnataka State. This is not a good practice since the yields obtained in this method are comparatively low. (i) Broadcasting: After the land is ready incorporate the entire quantity of farmyard manure and fertilizers into the soil. Prepare small plots of 120x120cm (4x4ft) and broadcast seeds thinly. Thin out the seedlings after four weeks, retaining one seedling at 7.5cm apart. (ii) Drill sowing: After the land is ready apply the entire quantity of farmyard manure and fertilizers and mix them well in the soil. Drill the seeds cross-wise in both directions giving a spacing of 25 to 30cm.
Planting bulbs: Prepare ridges and furrows giving a spacing of 38cm (15”). Apply the entire quantity of FYM along with 50% N, the entire P205 and K20 in the furrows. Dibble small bulbs half way on the ridge at 15cm (6”) apart. Irrigate the plot after planting. Crop is top dressed with the remaining 50% N, six weeks after planting. Sept-Nov. is the best months for planting bulbs around Bangalore.
Manures and fertilizers: FYM: 30 t/ha and N:P:K @ 125:75:125 kg/ha.
Weed control: Onion is closely planted crop, which makes the manual weeding difficult. Chemical weedicides have been profitably used for the control of weeds. Basalin 1 litre a.i. per hectare as pre-emergent weedicide before transplanting found effective. Besides this a combination of chloraxuron (trade name: Tenoran) and nitrofen (Trade name ToK-E-25) at 1.0 + 1.0kg a.i. per ha. Applied is post-emergent to weeds, one week after transplanting of onion seedlings controlled most of the weeds.
Irrigation and inter-culture: Irrigate the field once in 4 to 6 days depending upon the soil and weather conditions. Onion being a shallow rooted crop, keep the field free from weeds particularly during the early stages of the crop.
Harvesting and yield: Irrigation should be stopped 15 days before harvesting to check the growth and to enable the bulbs to become firm and compact.The crop will be ready for harvest when the leaves turn yellow. The tops also fall at this stage. After harvesting and field curing for drying of leaves, leaves are cut leaving 2.5cm at neck. An average crop can yield up-to 20,000kg per hectare (8,000kg/acre). A crop raised with care may yield up-to 35 to 45 tones/ha.
Curing: If season is mild the bulb after harvesting is left in the field for curing which makes it firm and dry, where as in hot weather the bulbs are removed to the shade for curing. It takes generally 6-8 days. Bulbs should be saved from rains and direct sunlight. Injured, rotten, diseased and thick-necked bulbs should be sorted out at the time of curing before storage.
Storage: Onions are stored in a well-ventilated place with lot of aeration and sunlight. Onion bulbs are packed in perforated gunny bags and stalked in vertical column, one above the other. However, height of such vertical column should not exceed more than 5 feet and should have sufficient space all around and bottom.

Crop Production