Everything you need to know about sunflower cultivation, harvest and growth. Learn about:- 1. Description of Sunflower 2. Cultivation of Sunflower 3. Climate & Soil Suitable 4. Land Preparation 5. Diseases & Pests 6. Harvesting 7. Sunflower – Seed Oil 8. Medicinal Action and Uses.
Contents:
- Description of Sunflower
- Cultivation of Sunflower
- Climate & Soil Suitable for Growing Sunflower
- Land Preparation for Sunflower Cultivation
- Diseases & Pests of Sunflower
- Harvesting of Seed
- Sunflower – Seed Oil
- Medicinal Action and Uses of Sunflower
1. Description of Sunflower:
An annual herb with erect, rough, hairy stem, 2-15 ft. high; leaves 4-12 in. long, alternate, long-stalked, broadly ovate to cordate, coarsely toothed, roughly pubescent on both sides; flower heads usually 3—6 in. wide, but attaining 12—24 in. width under cultivation: flowers single or double, terminal on the main axis and branches: receptacles flat, more frequently dilated and convex- ray florets yellow, surrounding a brown purple centre of disc florets; seeds (achenes) cylindrical, obovoid-compressed, 3/8 in. long and ¼ in. broad, white, black or striped grey and black; pappus falling early. Sunflower is self -sterile and fertilization is normally effected by insects.
2. Cultivation of Sunflower:
For cultivation as oilseed or fodder crop, a number of selections of sunflower are known, varying markedly in height of growth, diameter and colour of heads, shape, size, colour and oil content of seeds and suitability for different conditions of soil and climate. They can be divided primarily into three distinct types, viz., giant, semi-dwarf and dwarf. The giant types are 6-14 ft. tall, generally late maturing and bear heads 12-22 inches in diam.; the seeds are large, white or grey with black stripes, but the oil content is rather low.
The semi-dwarf types are 4½ -6 ft. tall, early maturing, and bear heads 7—9 inches in diam.; the seeds are smaller, black, grey, or striped and the oil content is higher. The dwarf types range from 2 to 4 ½ ft. in height, are early maturing and bear heads 5 ½ —6 ½ inches in diam.; the seeds contain a high percentage of oil.
Among the important commercial types cultivated in different countries are- giants—Russian Giant, Giant White, Manchurian and Grey Stripe; semi-dwarfs—Pole Star, Southern Cross, Mars and Jupiter; dwarfs— Sunrise, Mennonite, Advance and Arrowhead.
Sunflower is grown in India mainly an ornamental plant. A large number of horticultural types, are cultivated. Efforts made to cultivate sunflower as an oilseed or fodder crop have so far proved unsuccessful and nowhere has it become established as an economic crop. Some of the types tried are Giant Russian, Sunrise, Mennonite and Advance; of these, Mennonite and Advance appear to be promising for oil and Giant Russian for fodder.
However, in comparison with oilseeds like groundnut, sunflower or niger, which are all well established, sunflower has no marked advantage. In recent years, seeds of commercial types have been obtained from Canada, Australia, U.S.S.R. and Hungary and are being tried in several centres.
3. Climate & Soil Suitable for Growing Sunflower:
Sunflower thrives at medium and high elevations in the tropics. It requires a warm climate with moderate rainfall and shows a somewhat wide range of tolerance to wet and dry conditions. It is drought-resistant and can withstand several degrees of frost.
It is adapted to a variety of soils and does well on light, rich, calcareous or alluvial soils and does not require any manuring. It does not thrive on acid soils, water-logged lands or steep slopes. In highly fertile soils it tends to grow very tall, lodge or mature late; the yield of seed is also poor due to production of blind seeds in the heads.
4. Land Preparation for Sunflower Cultivation:
When grown as an oilseed or fodder crop, sunflower usually follows a crop which has been manured. The land is prepared to obtain a fine tilth and seeds are sown broadcast or in drills in the beginning of April; seeds may also be dibbled in. They are generally sown 1- 1 ½ in. deep in rows 2-3 ½ ft. apart, the spacing between plants in the row being 6-12 in. The seed rate varies according to the type sown. When planting dwarf or semi-dwarf types for oilseed purposes, the seed rate ranges from 4 to 6 lb. per acre, while for giant types, the range is 6 to 8 lb. per acre.
For green fodder or ensilage purpose, the seed rate is about 36 lb. per acre. Seedlings when 3-4 in. high are thinned out to 12-18 in apart. Sometimes, seeds are sown in nursery beds and transplanted in the field when 4-6 in. high. The field is weeded in the early stages, but once the crop is established (12-18 in. high), no further cultivation is needed. When plants have reached a height of 3-4 ft. the inferior flower heads are removed, leaving only 4-5 on the main stem.
Attempts have been made to propagate sunflower by grafting on jerusalem artichoke (Helianthus tuberosus). The resulting grafts are reported to be more vigorous and the seeds produced are richer in oil and low in husk content. The progenies of the first, second and third generations combine the vigour of jerusalem artichoke, with the earliness and productiveness of sunflower; but the capacity of H. tuberosus for tuber development is partially or completely lost.
Sunflower is an exhausting crop and makes heavy demands on soil minerals. In order to restore the soil, it is advisable to follow sunflower with a leguminous crop like guar, gram and berseem or bum the stalks and spread out the ash as is done in Russia. Manuring with artificial fertilizers is not recommended as it is reported to lower the oil content of the seed.
For ornamental purposes, sunflower is raised from seeds or by vegetative means. In the case of annual types, propagation is done by seeds or cuttings and in the case of perennials by division. Seeds are best sown in masses in beds or borders. Since they are gross feeders and make vigorous growth, they should be thinned out to get well-developed flowers; they also need staking in order to prevent them from falling down.
5. Diseases & Pests of Sunflower:
Among the diseases affecting sunflower in India, the following may be mentioned: rust due to Puccinia helianthi Schw., stem-rot caused by Sclerotinia sclerotiorum (Lib.) Mass., and grey mould due to Botrytis cinerea Fr. Many pests feed on sunflower at various stages of growth and cause considerable damage. The more serious among them are – wire worm, cut worm, web worm, aphids, weevil, moths and beetles. Considerable damage is also caused by birds, pigeons, finches, rabbits and hares. Sunflower plant is sometimes attacked by broom-rape (Orobanche sp.), a flowering plant parasitic on roots.
6. Harvesting for Seed:
The crop comes to maturity in 4-5 months after sowing. It is left in the field until the colour of the back of the head changes from green to yellow and the seeds become loose. The heads are cut before the seeds are quite ripe to avoid loss by shedding, or whole plants may be uprooted and the heads cut off with a sickle, knife or clippers, and exposed face up between rows to dry.
When thoroughly dry, the heads are threshed. They are placed on racks or piled, face downwards on floor and beaten with flails; they may be rubbed face downwards over a metal piece fixed in a wooden frame; they may be passed through a modified maize Sheller or gently pressed against revolving cylinders studded with nails.
Threshed seeds are spread out in a thin layer on a dry airy floor and turned over occasionally until dry, and cleaned from dry florets and other light impurities by winnowing. Dry seeds keep well for a number of years and retain their vitality if stored in a cool dry place. Rapid rise of temperature has been observed in piles of seed, especially if the moisture content exceeds 12%.
The yield of seed varies from about 300 lb. to 3,360 lb. per acre depending upon the type cultivated, fertility of the sort, and cultural practices; the average yield reported from different countries is 780—1,340 lb. per acre. In the trial cultivations of Giant Russian sunflower in India, yields upto 1,430 lb. and 1,900 lb. have been obtained in Mysore and Bombay respectively.
7. Sunflower – Seed Oil:
The oil content of the seed ranges from 22 to 36% (av. 28%); the kernel contains 45-55% oil. Intensive selection work in U.S.S.R. has led to the isolation of strains which yield seeds with thin husks and high oil content (av. 40%). The oil is usually extracted in U.S.S.R. and other European countries from dehulled seeds by cold pressing followed by hot pressing in hydraulic presses; the average yield is 22-29%.
The component glycerides were – palmito-oleolinolein, 14.88; stearo—oleolinolein, 15.63; oleodilinolein, 24.23; and dioleolinolein, 45.26%. The oil contains appreciable quantities of vitamins A, D and E, sterols, squalene and other aliphatic hydrocarbons, terpene and methyl ketones (chiefly methyl nonyl ketone)
The phosphatides (0.1—0.2%) present in the oil are lecithin (38.5%) and cephalin (61.5%); they occur in combination with protein and carbohydrates. The component fatty acids of the total phosphatides are- palmitic, 14.7; stearic, 5.1; arachidic, 9.5; oleic, 19.3; linoleic, 45.9; and unsat. C20-22‘, 5.5%. The foots from sunflower seed oil refining may be employed as a commercial source of phosphatides.
Extraction of Oil:
For the extraction of the oil, the seeds are bruised, crushed and ground to meal in a five-roller mill, under chilled iron or steel cylinders. The meal, after being packed in bags, is placed in hydraulic presses, under a pressure of 300 atmospheres or more, and allowed to remain under pressure for about seven minutes. All edible oils are thus obtained and are known in commerce as ‘cold-drawn oils’ or ‘cold pressed oils.’
As a preliminary operation, the seeds are freed from dust, sand and other impurities by sifting in an inclined revolving cylinder or sieving machine, covered with woven wire, having meshes varying according to the size and nature of the seeds operated upon. This preliminary purification is of the greatest importance.
The seeds are then passed through a hopper over the rollers, which are finely grooved, so that the seed is cut up whilst passing in succession between the first and second rollers in the series, then between the second and the third, and so on to the last, when the grains are sufficiently bruised, crushed and ground.
The distance between the rollers can be easily regulated, so that the seed leaving the bottom roller has the desired fineness. The resulting more or less coarse meal is either expressed in this state, or subjected to a preliminary heating, according to the quality of the product to be manufactured. The oil exuding in the cold dissolves the smallest amount of colouring matter, etc., and hence, has suffered least in its quality.
By pressing in the cold, only part of the oil or fat is recovered. A further quantity is obtained by pressing the seed meal at a somewhat elevated temperature, reached by warming the crushed seeds either immediately after they leave the five-roller mill, or after the ‘cold-drawn oil’ has been taken off. The cold pressed cakes are first disintegrated, generally under an edge-runner. This oil is of a second-grade quality.
Vertical hydraulic presses are at present almost exclusively in use, the Anglo-American type of press being most employed. It represents an open press, fitted with a number (usually sixteen) of iron press plates, between which the cakes are inserted by hand. A hydraulic ram then forces the table carrying the cakes against a press-head and the exuding oil flows down the sides into a tank below.
According to the care exercised by the manufacturer in the range of temperature to which the seed is heated, various grades of oils are obtained.
8. Medicinal Action and Uses of Sunflower:
The seeds have diuretic and expectorant properties and have been employed with success in the treatment of bronchial, laryngeal and pulmonary affections, coughs and colds, also in whooping cough. The following preparation is recommended- Boil 2 oz. of the seeds in 1 quart of water, down to 12 oz. and then strain. Add 6 oz. of good Holland gin and 6 oz. of sugar. Give in doses of 1 to 2 teaspoonful, three or four times a day.
The oil possesses similar properties and may be given in doses of 10 to 15 drops or more, two or three times a day.
A tincture of the flowers and leaves has been recommended in combination with balsamics in the treatment of bronchiectasis. The seeds, if browned in the oven and then made into an infusion are admirable for the relief of whooping cough.
Tincture of Helianthus has been used in Russia. Kazatchkoft says that in the Caucasus the inhabitants employ the sunflower in malarial fever. The leaves are spread upon a bed covered with a cloth, moistened with warm milk and then the patient is wrapped up in it. Perspiration is produced and this process is repeated every day until the fever has ceased.
A tincture prepared from the seed with rectified spirit of wine is useful for intermittent fevers and ague, instead of quinine. It has been employed thus in Turkey and Persia, where quinine and arsenic have failed, being free from any of the inconveniences which often arise from giving large quantities of the other drugs.