"Onion crop is raised by various methods"
Onion Booklet No. 103 Vegetable Production: VPS - 14 Contents Preface I. Introduction II. Climate III. Soil IV. Nursery Raising V. Sowing VI. Preparation of Land VII. Manures and Fertilizers VIII. Irrigation IX. Interculture X. Varieties XI. Crop Rotation XII. Diseases XIII. Insect Pests IX. Harvesting and Yield X. Storage and Marketing XI. Seed Production XII. Medicinal Value XIII. Uses and Composition XIV. Economics of Cultivation Preface Onion is an important vegetable not only in India but all over the world. It is also used as spice and green vegetable. This booklet describes the cultivation of onion in detail. Dr. K. T. Chandy, Agricultural & Environment Education I. Introduction Onion is an important vegetable crop grown all over the world. Its demand is world wide. The onion is grown for consumption in the green stage as well as mature bulb. It is grown especially in South and Central India. Onions are a major crop in many tropical countries, being valued for its flavoured nutritive value. It is probably a native of Asia, perhaps from Palestine to India. The crop has been known for its various uses in Egypt since 600 B.C. There are some religious books like Holy Bible, which describes its importance as food, medicine I and mummification. Onion is grown and distributed in all parts of the world. The important onion growing countries of the world are China, India, USA, USSR, Japan, Netherlands, Spain, Turkey, Brazil and Egypt. China and India are the leading onion producing countries. In India, onion is cultivated very extensively in Maharashtra and Gujarat as a cash crop due to its high potential for export. More than 20 % of the area under its cultivation is found in Maharashtra which accounts for 30 % of total onion production. The other states are Himachal Pradesh, Orissa, Kamataka, Uttar Pradesh, Tamil Nadu and Madhya Pradesh. II. Climate Onion grows under a wide range of climatic conditions but mild season without great extremes of heat or cold or excessive rainfall is best suited. It requires a temperature of 12-25°C before bulbing and 15.6-21.loC for bulb formation. The plant is somewhat hardy and can withstand freezing temperature. It can be grown as a rainfed crop at 1500 to 2100 metres elevation between April and August. In places where the annual rainfall exceeds 25 to 100 cm, the onion does not thrive well. It requires 70 % relative humidity. Exposing plants to very low temperature in the beginning favours bolting and hence the transplanting of seedlings before 15th of December (plains) is never recommended. Likewise sudden rise in temperature favours early maturity of the crop which results in small sized bulbs. Thus, delayed transplanting after 15 January is also not desirable as the plants are exposed to high temperature. III. Soil Onion grows in almost all types of soil from sandy loam to heavy clays. The clay is not satisfactory unless well supplied with humus to lighten them. Soils which retain enough moisture, allow proper expansion of the bulbs and well supplied with humus, are best suited for onion cultivation. Onion matures earlier in sandy soils than in heavier ones. The best pH ranges from 6.5-7.8. IV. Nursery Raising Proper nursery management and transplanting are important operations in the onion crop production. About 0.05 hectare nursery bed area is enough for transplanting one hectare of land. The soil should be of a good physical character, well pulverized to hold water and should not get dry soon. Plough the land for nursery bed 5-6 times and remove all the stones, remains of previous crop, weeds etc. Apply half tonne of well decomposed farmyard manure (FYM) and mix well with soil. Make small beds 3 meter long; 1.2 meter wide and 10 cm high. Press the soil firmly at the corners and along the sides to prevent excessive drying and setting. Each bed should be well leveled and make a slight slope so that excess of water may not stagnate. The distance between beds should be at least 30 centimetre. Seeds are sown either by broadcast method or in lines. Sow the seeds in lines 50 mm to 75 mm apart to facilitate the removal of seedlings for transplanting, quick weeding, spray of pesticides etc. Keep the nursery bed moist but it is not watered till the seedlings emerge out. Seedlings are available for transplanting in 6- 7 weeks for kharif and 8-9 weeks for rabi crops averaged seedlings result in number of bolters, whereas under aged cause higher percentage of plant mortality. Cover the seeds with a thin layer of soil. The green houses can also be used to raise the seedlings. V. Sowing Sowing is an important practice for onion cultivation because any alteration made on the seed rate, time of sowing and sowing method can reduce the yield significantly. So care must be taken to adopt appropriate sowing practices. 1. Seed rate The seed quantity required to raise the seedlings for one hectare main field is about 5-7 kg, purchased from some reliable source. For direct sowing, the seed required in the main field is about 1.6-20 kg of certified seed. 2. Sowing time Sowing or transplanting of seedlings can be carried out in a wide range of weather conditions. The most suitable time for sowing the seed in nursery and subsequent transplanting in the fields for maximum yield and better quality is different for different states. In Maharashtra, seed for early kharif crop is sown in nursery in early June and transplanted by the end of July, whereas the usual kharif onion seed IS sown in late August in nurseries and transplanted in mid-October. Sowing :. times for various regions of India are given in table-I. Table 1 : Sowing time for onion Sl.N Region Crop Nursery Transplanting o. sowing 1 Maharastra Kharkif Mid-August Mid-October 2 Rabi Early Mid-December 3 Northe India Kharif June-July July-sugust 4 Winter Oct-Nove Dec-Jan 5 Madhya Winter December January Pradhesh 6 Hills Summer March-May April-June 7 A.P Early winter Oct-Nov Nov-Dec 3. Sowing methods Onion crop is raised by various methods, depend- ing upon the circumtances of the farmers. These methods are (a) transplanting, (b) direct seed sowing and (c) planting bulbs in the field. However, the method of i nursery raising and subsequent transplanting is the best for high production and better quality. a. Transplanting When the seedlings are 6-8 weeks old and 15 cm high, they should be removed from the nursery beds and transplanted in the main 'field at a distance of 15-20 cm I 1 between lines and 7-10 cm between plants or seedlings. Irrigate the field soon after transplanting. The transplanting should be done either in early hours or late in the evening to avoid the drying of seedlings. Care must be I take~ to discriminate the seedling with damaged roots or diseases. b. Direct seed sowing Seed (16-20 kg) is sown by hand kera method or drill method to ensure seed depth 2-3 cm in lines at 30 cm apart. After 6-8 weeks, spacing between plants is adjust- ed to 10 cm by thinning and gap filling operations. This method requires more field labour for weeding at 10 days interval. c. Planting bulbs in the field Small and medium sized bulbs about 10-12 quintal are dibbled keeping 30 cm distance between lines and 15 cm between bulbs. Irrigation can be applied within one to two days after dibbling. VI. Preparation of Land Plough the soil 5-6 times up to a fine tilth level. The field onion matures early in sandy soils than in any other soils. Remove all the stones, weeds from the field to avoid weed infection. Sandy loam soils when well supplied with humus and heavy fertilizers are satisfactory for onion growing. For the early crop mulch soils are ideal as they can be prepared easily. Mix the farmyard manure properly at the last ploughing. VII. Manures and Fertilizers In general, the soil for onion growing should be liberally manured and fertilized but the requirement of the nutrients will depend on soil type, region of grow- ing and removal of major nutrients. 1. Doses of fertilizers Onion crop is a heavy feeder of nitrogen and potash. The application of nitrogen increases the weight and size of bulbs. It is difficult to recommend a common dose of manures and fertilizers for all types of soils in different parts of the country because the soil fertility, climate etc changes from region to region. Some of the recommendations given by The All India Coordinated Vegetable Improvement Project are given in table 2. Table 2 : Fertilizer recommendations for onion crop (in kg/ha) Sl.No. Region Nitrogen Phosphorus Potash 1 Delhi 150 60 - 2 Jabalpur 150 69 - 3 Karnal 150 80 - 4 Uttar pradesh 80 50 50 5 Punjab 112 50 28 2. Application of manures and fertilizers Manures, about 20-25 cartloads, prepared from green-leaves or cow dung are mixed with soil at the last ploughing. According to ICAR recommendations, the full doze of phosphorus and potash with half doze of nitrogen be applied as basal dose, 2-3 days before transplanting the seedlings. The remaining half-dose of nitrogen should be applied after one month of transplanting as topdressing, when sufficient moisture is available in the soil. VIII. Irrigation Onion has a shallow root system (8 cm depth), therefore, regular irrigation is needed. In the initial growth period water requirement is low and the frequency of watering the crop in the beginning is less comparing to later stage of growth. More water is equally harmful to the plants as the leaves turn yellow. Kharif crops requires water when there is dry spell during the rainy season. Irregular irrigation results in poor yield. The crop planted in June needs 5-6 irrigations, while in October 12-15 irrigations and the summer crop need 15-20 irrigations. In December, 13 days interval and in January 10 days interval should be kept between the irrigations. Under Delhi conditions onion crop requires about 45.7 cm. of water. The number of irrigations recommended are three in January, two in February, four in March, five in April and two in May. On clay soils it should be ' about 12 irrigations in total. The crop requires about 18 irrigations from transplanting to harvest. Sprinkler irrigations and application of nitrogenous fertilizers by foliar spray gives higher yields. The moisture stress at maturity stage hastens bulb formation, ,I while during development periods, results in bolt formation. Flowering and seed formation stages requires ! more irrigations. i IX. Interculture lnterculture practices include earthing up, weeding and gap filling. 1. Weeding Onion needs a number of weedings to get a better J crop. Frequent hoeing and weeding of the crop is essential. As the crop is shallow rooted it needs only light hoeing especially at early stages of growth. Generally, 2-3 weedings are sufficient to keep the field free from the weeds. Hand weeding is laborious and costly due to close spacing. Chemical method of weeding increases the bulb yield by eliminating weed competition. Application of Propachlor at the time of weed emergence or application of Treffan E.C.-2 @ 4 litres/hectare before planting seedlings or weedicides such as Tok £-25 at 8 litres per hectare or Basalin @ 0.5 litre per hectare control the weeds satisfactorily. 2. Earthing up Earthing up is done after two months of the planting. 3. Gap filling The gap filling is also done to maintain the plant population after one or two weeks of the transplanting. X. Varieties Onion varieties are in a state of rapid change. The number of hybrid varieties is increasing rapidly each year. Onion varieties are known by their size, shape, colour, keeping quality, pungency or their maturation habits. Much importance has been laid on the development of high yielding varieties (HYV) and their production techniques by the inception of All India Co-ordinated Vegetable Improvement Project by ICAR. The important varieties are as under. A. Red onion There are seven red onion varieties explained here. 1. Pusa Red In this type the bulb is medium in size, purple red, flattish round, each bulb weighs 70-90 g, less bolting and ! with poor pungency. The variety requires short to intermediate day length. It matures in 123-140 days after transplanting. It is commonly grown in India. It is a high yielding variety and yields about 257-300 quintals per hectare. Bulb is about 5.84 cm long and 6.7 cm in breadth. 2. Punjab Selection The bulbs are red in colour, quite firm and having good keeping quality. It is tolerant to purple blotch and thrips and suitable for dehydration. The bulbs are globular in shape and measure 5-6 cm across and each bulb weighs 50-70 grams. 3. Pusa Ratna The bulbs are large, slightly oblate with attractive deep red and are exposed above ground at maturity. Pungency is less and have good storage quality. The leaves are dark green with waxy bloom and plant is about 30 cm high. It is an early maturing variety with high yield. Its average yield is about 179 quintal per hectare. The mean length of the bulb is 3.1 cm and breadth is 6.3 cm. 4. Agri-found Dark Red The bulbs are red, tight skin, moderate pungency and globular in shape. It matures in 150-160 days and can grow as kharif season crop. It has a good storage capacity. 5. Arka Niketan The crop matures in about 45 days, yields about 239 quintal per hectare. It is mainly a kharif crop. Bulbs are globular at their neck and of attractive colour, weighing about 100-180 g each, with mean length of bulb 6.30 cm and breadth 6.09 cm. The bulbs can be stored at room temperature for about 5 months. It has high dry matter content. 6. Arka Kalyan It can be grown as kharif crop, matures in about 140 days and yields about 274 quintal per hectare. Each bulb weighs about 100-190 g, about 6.5 cm long and 7.3 cm wide. The bulb is deep pink coloured. The leaves are slightly resistant to the purple blotch. 7. N-2-4-1 (The variety is tolerant to alternaria blight. The bulb is about 5.65 cm long and 6.3 cm wide and mild pungent. The crop yields about 190 quintals per hectare. It has a good keeping quality. B. White onion The bulbs are white, globe shaped, about 3.72 cm long and 6.55 cm wide. It yields about 139 quintals per bectare. It has a good keeping quality. 1. Pusa White Round The bulbs are white, suitable for dehydration, roundish flat, about 4.65 cm long and 6.21 cm wide. It yields about 169 quintal per hectare. 2. S-48 It has a good keeping quality. The plant has 8-9 leaves. Bulbs are flattish round having good flavour and texture. The plant can attain 40-60 cm height. C. Desi varieties Main desi varieties are Red Globe, White Globe, Yellow Globe, White Patna, Nasik Red, Large Red, Patna Red, Bellery Red and Jhulia, D. Imported varieties White Portugal, Silver Skin, Australian Brown, Sweet Spanish, Red Italian, Early Grano. E. Selections from Punjab varieties A number of varieties released by Maharashtra state like N-404, N-491, N-53, all red type and many kharif varieties are nearly selections from Punjab varieties. F. American or pungent type They generally produce bulbs of small size, dense texture, strong flavour and better keeping quality. The most important are Bregham Yellow Globe, Yellow .Globe Danvera, Early Yellow Globe etc. Ebenezer is a common yellow variety. Red Wethers Field and Southport Red Globe are red varieties. Southport White Globe has high pungency. White coloured are good for storage. XI. Crop Rotation This practice is an important aspect while growing the onion crop to get more and more yields from a given piece of land, for the improvement of economic and financial position of the farmer. The common crop rota- tions are given here. A. Onion (Dec. to May)-Bhindi (June-Sep.)-Potato (Oct.-Sept.) B. Onion (May-Sep.)-Mustard (Nov.-April) C. Onion (May-Sep.)-Oats (Nov.-April) D. Onion (Jan.-May)-Lobia (June-Oct.)-Potato (Oct.- Feb.) E. Onion + Tomato -Cauliflower + Cabbage Intercropping gives more benefits than single crop. This practice should be adopted. It should be designed in such a way that in case of unfavourable weather at least one crop will survive to return economic yield thereby providing the necessary increase against the unpredictable weather. XII. Diseases Onion is attacked by a number of diseases, some of them are as under: 1. Pink root The root turns pink, shrinks and dies. The causal organism is a fungus which lives in soil. The plant pro- duce new roots but do not complete with the growing season so yield is lowered. It is more serious in hot, dry weather and at the time of bulb formation. Control Adopt crop rotation and apply calcium cyanamide at the rate of 2500 litres per hectare. 2. Onion smut It is caused by Urocystis cepulae. The fungus lives in the soil year after year. It is inactive at 30°C or above. The fungus attacks on young seedling plants. Dark, slightly thickened areas on small leaves of younger seedlings occur. Then other leaves are attacked. They are swollen and try to bend downwards. Then small black pustules appear. Control (I) Treat the seed with Thiram 3 g per kg of seed, (2) Grow disease resistant varieties like Nebuka, etc. and (3) Apply fungicide in furrows along the lines of seed sown in nursery. 3. Neck rot It is caused by the fungus Botrytis alii. It is found in all regions where bulbs are stored. The fungus also attacks injured leaves. The lesions appear as sunken, dried areas near the node or the bulb or involve whole bulb. The fungus over-winters in the diseased onions in storage. Control i. Harvest the crop when the tops are completely dry. ii. Store the onion at about O°C and with humidity at about 65 % with good dry air circulation. iii. Remove the diseased plants and bum them. 4. Downy mildew The disease spreads rapidly during cool and wet weather. Some varieties of onion have the fungus during winter also in storage. Dew collects on the plant at night by which the spores germinate and enter the onion leaf. Control i. Grow resistant varieties. ii. Spray Zineb, about 6-10 application at an interval of 6 to 8 days. iii. Remove diseased plants and burn them. 5. Stemphylium blight Small, yellow to pale orange spots appear in the middle of flower stalk as well as leaf on one side but other side remain quite green. These spots then become spindle shaped, diffused lesions then coalesce. The whole flower stalk is attacked in a short period affecting seed development and the leaves of the bulb crop dry prematurely. Control (i) From first week of February, spray the crop with Dithane M-45 -2-5 g per litre of water, repeat the process at fortnightly interval, total 4-5 sprays are sufficient. (ii) Remove the diseased plants and burn them. (iii) Adopt the crop rotation. XIII. Insect Pests The onion is attacked by a number of pests some of them are described as under. 1. Onion thrips The thrips are very small (1-2 mm long) in size, elongated and creamy yellow in colour. The nymphs and adults both suck the cell sap of the seed stalk and young leaves. The central leaves become curled while the outer leaves turn brown at the tips. The insect causes more damage during dry weather. Control i.Spray the crop with Thiodan @ 2 ml per litre of water. ii. Spray Rogar @ 1 litre per hectare for 2-3 times at 10 days interval kills the insect. iii. Remove the grasses and weeds from the field to destroy the alternate hosts. iv. Grow fairly resistant varieties like Grano, Sweet Spanish, Crystal Wax etc. 2. Onion maggot The adult lays eggs on the plants near the base or in cracks of the soil. The adult maggot measures about one third inch long and is translucent white in colour. The maggots crawl on the plants behind the leaf sheath and enters the bulb. For about 14-21 days it feeds then bore through underground stem portion into the bulb. The bulb becomes watery and turn brown from the tip to downwards. The infested plants turn yellowish brown and ultimately dry up. Control i. Infected bulbs should be buried in pits and covered with soil about 30 cm in early spring before the adult emerges out. ii. Dust the bulbs with 10% DDT at the rate of 25 kg per hectare. iii. Use Heptachlor @ 1 kg per 250 kg of seed bulb. iv. Adopt crop rotation. 3. Tobacco caterpillar The moths are greyish in colour. The caterpillars feed gregariously on leaves in nursery and fields. They are found everywhere and breed throughout the year. They eat the young foliage leaves which results in very less bulb formation. Control Dust the crop with BHC 10 @ 25-30 kg/hectare and adopt crop rotation. IX. Harvesting and Yield The onion crop is ready for harvesting within 4 to 5 months, depending upon the variety. When the falling of tops start, and the leaves turn yellow, the onion should be pulled out with a hand hoe. Bulbs are considered mature, however, when the neck tissue begins to soften and the tops are about to abscise and decolourise. Development of pigment and the characteristic pungency of the variety are also harvest indices of onion. In winter normally there is no top fall and yellowing of the leaves, and development of pigmentation and true size and shape are taken as index for maturity. As soon as the bulbs attain this condition, they should be harvested and placed in windows to prevent sun scalding and kept dry to avoid sprouting. They can be removed to shady place, for curing, if it is a hot season. If the season is mild the bulbs are left in the fieJd for curing which makes it firm and dry. About 250-300 quintal/hectare of bulbs are obtained by growing the crops, under recommended package of practices. X. Storage and Marketing After harvesting onion is stored by the farmers in ordinary storage structures called 'chawls" 'kupes' and 'chali' in Maharasthra, Haryana and Bihar respectively. For storage, onion should be well matured and cured well. The rooms should be ventilated which have low tempera- ture and dry atmosphere. The bulbs should be well ex- posed to air by all sides. The room temperature should be about O°C and relative humidity 64 per cent. The store should be cleaned properly. The sprouting is influenced by humidity. Onions are graded on the basis of their size, colour, variety and other factors like free from insects pests, disease, injury, stage of maturity, etc. A quality bulb should be: (1) Free from diseases and insects (2) Free from moulds (3) Properly cured and dried (4) Uniform in shape, colour and pungency (5) Free from any damage caused by sun burn, mechanical or other injuries, dry sunscald and sproutings. The grades are as: (a) Big size (bulb 35-45 mm in diameter) (b) Medium (bulb 25-35 mm in diameter) (c) Small (bulb 15-20 mm in diameter) (d) Mixed (bulbs of different sizes not below 15-20 mm in diameter.) India is one of the important producers of onion which accounts for 10% of the world production. It produces about 20 lakhs tonnes of onions annually. About 10% is lost in the course of marketing, about 5 % of the total produce is exported and the remaining 85 % is utilized internally for domestic use and seed purposes, a very little quantity is used by the processing industry. A number of agencies like producers, wholesalers, commission agents, cooperatives etc. take part in the marketing of onions. Methods adopted for marketing of onions in the country are: (1) Open auction system (2) Under cover or Hatha system (3) Tender system (4) Open agreement system. XI. Seed Production Onion seed is produced from best selected bulbs of the previous years harvest. For production of high yield and good quality seeds, proper attention should be given on any of the following methods of seed production. 1. Seed to seed method In the months of September to November, the good standard seeds are sown in the nursery beds. Seedlings are transplanted and grown to get matured bulbs. These bulbs are replanted next year to produce seed. Thus seed to seed method takes about 2 years from the sowing of the parent seed in nursery beds to the actual harvest- ing of the progeny seed. 2. Bulb to seed method Twelve thousand bulbs are planted in the beds or on one side of the ridges (45 cm x 30 cm) about 7.5 cm deep in the month of October. About 20 kg of nitrogen and 9 kg of phosphorus in the form of ammonium sulphate and superphosphate respectively should be added one and half months after j planting. Light irrigation should be given after planting I followed by other irrigations after every 7-10 days depend- j ing upon the weather and soil along with 2-3 earthings and 2-3 weedings. After about 10 weeks of planting j, flowering starts and about 6 weeks, seeds ripen. The II ripening of seeds is not uniform. Cut the ripened clusters : in 3 to 4 cutting, at an interval of one week for harvesting the whole crop. Spread the head on floor in a well ventilated and shady place. Then the seed heads are threshed by hand and the trash is removed by fanning and screening. The seeds are cleaned, and packed in tins or in alkathene bags to the brim and kept in a cool place. About 225 seeds make one gram. Onion seed is a very short lived and retains the viability only for a year, so should be used immediately. About 400 to 800 kg of seed is produced from one hectare and about 30 to 56 quintal of bulbs are also produced which should be sold immediately. XII. Medicinal Value Juice extracted from the onion bulbs have numerous medicinal uses. It is used as medicine in faintness, head- ache and hysterical fits. Hot juice is dropped in the ear to relieve ear ache. Locally, it is applied to get relief from insect bites, scorpion stings and used as ointment for skin diseases. Mixed with vinegar it is useful for throat sore. Mixed with black pepper, its juice is a medicine for malaria fever. Roasted onion mixed with cumin, sugar, candy and ghee, gives relief in piles. XIII. Uses and Composition Onion is an important vegetable used both as raw and matured bulb as vegetable and as spice. Its bulb contains 87 % moisture, 1.2 % protein, 1 % fat, 11.5 % carbohydrates, some minerals like calcium, phosphorus, iron and an appreciable percentage of vitamin-B, riboflavin, nicotinic acid and ascorbic acid. It has got pungency due to volatile oil known as allyl-propyl-dis- ulphide. XIV. Economics of Cultivation Onion is a crop having great export potential in India. Generally, a farmer can generate Rs. 8,000 to 12,000 net income from one hectare of onion plantation. A format of economics involved in onion cultivation is given below and with the help of this format, cost of cultivation of onion can be calculated depending on the area and variety. A. Fixed cost 1. Cost of the land Rs 2. Cost of farm building, storage, structure, etc. Rs 3. Cost of fencing Rs 4. Cost of clearing, leveling and bunding of the land Rs 5. Cost of farm implements Rs 6. Cost of permanent or temporary irrigation system Rs B. Recurring cost 1. Cost of land preparation Rs 2. Cost of planting materials Rs 3. Cost of digging pits or preparing the ridges Rs 4. Cost of manures and fertilizers Rs 5. Cost of insecticides, fungicides and weedicides Rs 6. Cost of farm power Rs 7. Cost of transportation Rs 8. Cost of farm labour (paid and unpaid) a. land preparation Rs b. Training and pruning Rs c. Irrigation Rs d. Weeding Rs e. Application of insecticides and fungicides Rs f. Application of manures and fertilizers Rs g. Other intercultural operations such as weeding, thinning, etc. Rs h. Harvesting Rs i. Supervision of the crop j. Cleaning and grading Rs k. Packing Rs l. Storage and marketing Rs m. Any other labour involvement Rs n. Interest on fixed cost @ 10% Rs 9. Rent or revenue on the land Rs 10. Depreciation a. Farm structure Rs b. Farm machinery Rs 11. Repairs and maintenance Rs Total recurring cost Rs C. Income 1. Yield of bulbs Rs 2. Yield of seed Rs ,... Total lncome Net profit = Gross income -Total recurring cost Purchase value-Junk value Depreciation = ------------------------------------------ Life span Note: Junk value is calculated only on those articles which are saleable after their life span. The life span of farm building and farm machinery is 15 and 10 years respectively. %%%%%%%%%%%%%%%