Authors: 1Sheeshpal Choudhary, 2Mahendra Choudhary and 3Chouthu Ram Hakla
1&2Ph.D. Scholar Department of Agronomy, SKNAU, Jobner, Jaipur, Rajasthan- 303329, India
3Ph.D. Scholar Department of Agricultural Chemistry and Soil Science, SKNAU, Jobner, Jaipur, Rajasthan- 303329, India
Email of corresponding author: spkantwa@gmail.com
Importance of onion
Onion is the most important commercial spice crop grown in India and exported. Onion leaves and immature bulbs are consumed as vegetable. It is mixed in other vegetables and soups as spice and flavouring agent. It contains vitamin B and vitamin C and minerals Ca and Fe. It has medicinal properties and used against ear-ache, colicpain etc. The pungency in onion is mainly due to the presence of volatile oil allyl propyl disulphide in the bulb.
Climate: Onion crop can be grown in varied type of climatic conditions, but mild climate is most suitable. Extremes of heat, cold and rainfall are not suitable for growing onion. The rainfall requirement is 750 to 1000 mm/year. It requires bright sunny weather during bulb development stage therefore is grows well in rabi season.
Soil: Onion can be grown in alluvial, loamy medium type of soils. The soil should be well drained loose and friable. Heavy clay, marshy and alkaline soils are not suitable.
Varieties of Onion:- There are three types of Onion varieties is below:
A. Red Coloured Varieties:
Kharif season: Agrifound light red, Agrifound dark red, Baswant–780, Niphad – 53.
Rabi season: Niphad – 241, Niphad 2071 – 1, Pusa safed.
B. White Coloured Varieties: Niphad – 5- 7- 1, Niphad – 123-7-1, Phule safed.
Cultivation of Onion for Bulb Purpose:
Raising of Seedlings: Onion seedlings are raised on nursery beds prepared at high lying area. Nursery beds 3 m long, 1.5 m broad and 10 cm high are prepared. Seed rate is 5 to 6 kg per hectare. The seed is sown crosswise in rows made 10 cm apart from each other. Seed is covered by giving thin layer of soil. Beds are first irrigated at 3 to 4 days interval and later on at 8 to 10 days interval. Seedlings become ready for transplanting within 45 to 60 days when they attain the height of 10 to 15 cm.
Preparation of field for Transplanting: The land is ploughed 2 to 3 times. Colds are crushed with the help of main or harrow. 25 to 30 tons of FYM is mixed into the soil.
4. 2 to 3 harrowing are given to brought the soil to a fine tilth.
Seed rate and Time of Transplanting: Seed rate of onion for bulb purpose is 5 to 6 kg seed/ha. Onion can be grown at any time during the year. But most suitable time for transplanting onion in Maharashtra is July in Kharif and November in Rabi.
Transplanting of Seedling: Transplanting of onion can be done by two methods:
A. Flat Bed Method: Flat beds of 4m x 2.5m sizes are prepared with the help of sara yantra. The beds are soaked well by giving pre transplanting irrigation. Seedlings are transplanted at 15 cm x 7 cm distance. Only one healthy, vigorous growing seedling is transplanted at each spot. The bulbs obtained in flat beds are medium in size but the per hectare yield is high as compared to ridge and furrow method.
B. Ridge and Furrow Method: The ridges and furrows are prepared at 45 cm distance. One soaking irrigations is given before transplanting. Seedlings are transplanted on both the sides of the ridges by keeping 10 cm distances between two plants. Only on healthy seedling is transplanted at each spot. The bulbs obtained in this method are large in size but yield per hectare is less as compared to flat bed method.
Manuring:- 25-30 tonne FYM per hectare is mixed into soil at the time of land preparation. The dose of fertilizer is 50 kg N, 25kg P2O5 and 50 kg K2O/ha. Out of this 25 kg N and complete dose of P and K is applied to the bed just before transplanting. The remaining dose of 25 kg N is applied one month after transplating.
Irrigation: In kharif the crop is taken on rain water and usually there is no need of irrigation. In case of rabi crop first light irrigation is given just before the transplanting. Second light irrigation is given 4 days after transplanting. Other irrigations are given at 10 to 12 days interval in winter and at 7 to 8 days interval in summer. In all it needs 15 to 18 irrigations is more at bulb development stage. The need of irrigation is more at bulb development stage. Irrigation shall be stopped 15 to 20 days prior to date of harvesting.
Intercultivation: Weed intensity reduces the yield of bulbs thus frequent weedings are necessary to keep the field weed free. Generally three hand weeding are given at one month interval after transplanting.
Harvesting:- Harvesting time of onion depends upon the purpose, variety and planting time. For green leaves or vegetable purpose onions can be harvested at any time when leaves are green and not fibrous. For bulb purpose onion become ready for harvesting in 120to 140 days. At maturity the leaves turn yellow in colour and start drying form tips. When 75% leaves dried and droop down harvesting is done. The bulbs are pulled out by hand or dug out with the help of Kudali. The leaves and roots of bulbs are cut down.
Yield:-
1. Average Yield of kharif onion - 12 to 15 tons/ha.
2. Average Yield of rabi onion - 20 to 25 tons/ha.
Pests and Diseases of Onion
A.Important Pests of Onion:
1. Onion Thrips:- This pest suck the sap from the leaves during night and in early morning. Whitish spots are found on leaves which affects on the development of bulb.
Control:- Application of thimate 10 G @ 10 kg/ha. Spraying of Dimethoate 10 ml or endosulfan 20 ml in 10 lit water alternately at 15 days interval.
2. Leaf Eating Caterpillar: -Larvae feed on leaves and make the holes on it and feed inside the leaves.
Control:- Application of thimate 10 G @ 10 kg/ha. Spraying of Dimethoate 10 ml or endosulfan 20 ml in 10 litre water alternately at 15 days interval. Spraying of 0.65% lindane solution.
B. Important Diseases of Onion:
1. Damping Off: - Damping off caused by excessive moisture in soil and controlled improving drainage. This disease is found on seedlings in nursery. The seedlings turn yellow and rottened at ground level. Due to this, seedlings collapse on ground know as ‘damping off’.
Control:- Spraying of 1%. Bordeaux mixture or copper oxychloride 50 wp @ 25 kg in 10 litre of water. Spraying of Bavistin @ 10 gm in 10 litre water at 15 days interval.
About Author / Additional Info:
I am Ph.D. students in Department of Agronomy, SKNAU ,Jobner Jaipur