Sunflower (lat. Helianthus annus L.) or sunflower began to be cultivated 150 years ago in Russia, from where it spread throughout Southeastern Europe, and the main reason for sunflower production is the high proportion of oil in the seeds (25 – 53%). It got its name because of its specific movement after the Sun, which it follows during the day, and when the Sun sets, the flower turns towards the earth. It originated from Mexico and Peru, and was also a symbol of light and fertility. It was introduced to Europe in the 16th century, and was initially cultivated as an ornamental plant.
The sunflower has a well-developed root that penetrates the soil deeper than 2 to 3 m, and grows during the entire growing season. It has strong lateral roots that grow up to 120 cm in width and has a very good suction power. The stem is thin and soft at the beginning of its development and becomes woody over time. The height depends on the variety and growing conditions and ranges from 75 to 400 cm.
In varieties with an extremely high oil content, the stem does not branch. The leaves consist of a long and thick petiole and a round and slightly toothed blade. Blossom or so-called a sunflower head is a group of flowers that are located at the base, and bloom gradually, i.e. the barren flowers bloom first and then the fertile flowers. The head is divided into 9 – 10 zones according to which flowering takes place (9 – 10 days), and they are composed of 2 – 3 concentric circles of flowers. The flowers on the periphery bloom first, then those in the middle of the flower box, and after 8 – 10 days, the flowers in the center of the head begin to bloom. In the center of the head are small yellow-brown or red-brown tubular flowers, and around them there are tongue-shaped petals up to 10 cm long.
The sunflower is a cross-breeding species, and pollination takes place entomophilously. Bees stood out as the most efficient pollinators. Optimal temperatures for pollination and fertilization range from 20 to 30°C. During unfavorable weather conditions, the flight of insects is prevented, therefore incomplete pollination occurs, resulting in stunted fruits. Flowering lasts from June to September. Some types of sunflower resemble delusion.
The fruit can be black, gray or white in color, 7 – 23 mm long, and is called a pod or nut, but in practice it is called a seed. The fruits are protected from attack by the sunflower moth with a protective layer that makes them impenetrable. The formation of fruits begins with the growth of the seed mass when the tissues for the accumulation of oil, proteins and other compounds are formed. The growth of seeds after fertilization lasts about 2 weeks, followed by the phase of accumulation of oil and other substances lasting 20 – 25 days, and this is the most important period in the development of sunflowers. Oil synthesis begins 6 – 10 days after flowering.
As an important oil and protein crop, sunflower is widely used, and all parts of the plant can be used. Today, it is the most important crop for the production of edible oil. Sunflower protein is used to make meal for animal feed and protein flour, while the kernel can be used directly in the production of cakes, ready meals, bread and the like. Sunflower is grown on deep, fertile soils with a neutral reaction.
Types of sunflowers
According to the length of the vegetation, the assortment of sunflowers is divided into:
- Very early (under 100 days)
- Early (101-110 days)
- Medium early (111-120 days)
- Medium late (121-130 days)
- Late (131-140 days)
- Very late (over 140 days)
Most often, medium-early and medium-late varieties are grown, especially for oil production.
Of the mid-early varieties, the most notable are Apollon, Luka, Favorit, Fakin, Orion, Olio, Lucil, Barolo RM, NS Ronin, NS Konstantin, NS Romeo, NS Fantazija and Acer CL.
Apollo
The length of the growing season ranges from 110 to 115 days, it has a high yield potential (5 t/ha) and an oil content of 50 to 52%. It has a strong and developed root system that enables it to grow on different types of soil. It is characterized by high resistance to unfavorable conditions and sunflower diseases, and the optimal sowing time for a high yield is during April. It is sown at a distance within the row of 18 to 20 cm, and the optimal number of plants is 64,000 – 66,000 plants/ha.
Port
It has a high yield potential (6 t/ha) and oil (51-53%), very good fertilization of the central part of the head and a high hectoliter grain weight. The distance between rows when sowing is 20-22 cm, and the optimal number of plants is 60,000 – 65,000/ha.
NS Ronin
It has a lush growth and is resistant to lodging. It tolerates dry conditions well and can be grown even on poorer soils. It has a high genetic potential for yield over 5.8 t/ha, and the oil content is 48-50%. The optimal sowing pattern is 55,000 – 60,000 plants/ha.
NS Konstantin
Tolerant of diseases that cause leaf spots, the stem is of medium height and is extremely tolerant of lodging and breakage. The potential yield is over 5 t/ha, and the oil content is 45-47%. The recommended assembly is 55,000 – 60,000 plants/ha.
NS Romeo
It adapts to different soil types, tolerates drought well and is resistant to blight. The yield potential is over 5 t/ha, while the oil content ranges from 46 to 48%. The optimal sowing pattern is 55,000 – 60,000 plants/ha.
NS Fantasy
A high degree of fertilization is characteristic, the stem is of medium height and resistant to lodging. The genetic yield potential is greater than 5.3 t/ha, and the oil content is 46-49%. The optimal sowing system is 55,000 – 60,000 plants/ha.
Acer CL
The stem is of medium height and has medium early ripening. It has a high tolerance to diseases and lodging. Potential yield is up to 4.8 t/ha and high oil content.
Varieties of mid-late sunflower are: Barolo RM, NK Kondi, Util
Barolo RM
It is characterized by high tolerance to diseases and high fertility even in unfavorable growing years. It has a medium-tall stem with good lodging resistance. The oil content is 50-51%, and the recommended sowing system is 70,000 – 75,000 grains/ha.
NK Kondi
Adaptable to different conditions and types of soil and extremely uniform growth. It has a very high proportion of oil in the seeds and good resistance to drought and high temperatures. The potential yield is more than 5 t/ha, and the recommended cultivation system is 50,000 – 55,000 grains/ha.
Cultivation of sunflowers
For the highest yields, it is necessary to ensure as wide a crop rotation as possible, and the optimal time of repeated cultivation is 4-5 years. In addition, sunflower has a large amount of dry matter, for which it consumes a lot of nutrients, so adequate fertilization is necessary.
Matching cultures
The most favorable pre-crops are small cereals, legumes, hoeing, i.e. crops that leave the soil early. A broad crop rotation enables preventive protection against diseases and pest attacks.
Sunflower is a suitable pre-crop for wheat and corn.
Fertilization
To produce 100 kg of sunflower seeds, 4.4-6 kg of nitrogen, 1.6-3 kg of P2O5 and 8-18 kg of K2O are needed. In addition to being able to draw water from deeper parts of the soil with its deep roots, it can also absorb nutrients stored at that depth, so it tolerates weaker fertilization. For a high yield, NPK 7:20:30 or NPK 5:15:30 is introduced into the soil during basic processing on heavier soils. In the spring preparation, UREA or NPK 15:15:15 is introduced to the depth of the sowing layer with saucers. If NPK is applied, 10 kg/ha of KAN should be applied during inter-row cultivation. Roughly speaking, on medium-fertile and fertile soils, 2/3 of NPK should be introduced in the basic treatment, and 1/3 in pre-sowing preparation, while on soils of poorer quality, 1/3 of nitrogen is left for top dressing.
Watering
Since the sunflower has a strong and developed root, it has the ability to draw water from the deeper layers of the soil, so a large amount of water is not necessary for its development. The greatest need for water is in the period from flowering to grain filling. Excessive amounts of precipitation during the second part of the growing season (July – August) can cause the appearance of diseases.
Ground
Sunflower does not have great requirements regarding the chemical composition of the soil. It suits all types of soil, except shallow and skeletal. The most favorable soils for growing are deep fertile soils with a deep humus layer, neutral pH reactions.
Temperature
The minimum temperature for seed germination is 5°C, and the most favorable temperature for growth and development is between 20 and 25°C. In the early stages of development, it can withstand temperatures down to -6°C. In the phase of intensive oil synthesis, for the highest quality, temperatures should not be higher than 30°C.
Sowing sunflowers
Proven seeds should be used for sowing sunflowers, and two or more sunflower hybrids of different vegetation lengths should be sown on larger cultivation areas. Seed germination must not be less than 95%, and genetic purity must be at least 98%. Sowing begins in the period when the soil temperature has stabilized at 8-10°C at a depth of 5 cm, which is approximately in the first half of April.
Late hybrids are sown first, followed by mid-early and early hybrids. The sowing depth is determined with regard to the characteristics of the soil and the size of the seeds, i.e. on heavier soils it is sown 4-5 cm deep, and on lighter ones 5-6 cm deep. The sowing distance in a row is 18-32 cm, and between rows 70 cm.
The best sowing quality is obtained by using a pneumatic precision seed drill with sunflower plates. The required amount of seed is approximately 5-5.5 kg/ha.
Sowing time
The optimal time for sowing sunflowers is from April 10 to April 20, and only when the soil temperature reaches a minimum of 8°C. In some areas, the soil temperature warms up faster, so the first sowing is possible in the first half of March to the first half of April. On water-soaked soils, the first sowing should be done by the middle, and at the latest by the end of April.
Soil preparation for sowing
The optimal time for tilling the soil before sowing sunflowers is in the period from July to September. Depending on the type of soil, the plowing depth ranges from 30 to 45 cm. If the sunflower in the crop rotation comes after a culture that leaves the soil early, dusting and medium and deep plowing are necessary. Harrows are used in the spring cultivation of lighter soils, and disc harrows and seed drills are used for the cultivation of heavier soils. Before sowing, it is necessary to level the soil so that the sowing depth is even. The upper layer, up to 6 cm deep, should be loose, which is achieved with a seed drill. Preparation should be done 4-5 days before sowing in order to warm up and dry the top layer.
Cultivation in containers
Sunflower can also be grown as an ornamental garden plant that can be sown in jars or in the garden. Shorter hybrids (40-60 cm) are chosen that have a strong branched stem with multiple flowers that can be single or double and yellow, orange or red-brown in color. The most common cultivars are “Sundance Kid”, “Pacino”, “Big Smile”. Decorative sunflowers are sown in April, so that each seed is placed in a separate jar and stored at a temperature of 15 to 20°C. In the middle of May or the beginning of June, the plant is planted in the garden in a sunny place with a sufficient supply of water (it likes a lot of water) and feeding once a week during the summer months. They bloom from the beginning of July to October.
In addition to the garden, the sunflower is also used as a cut plant, which is used for decorating and arranging flowers.
Maintenance and care
For proper sprouting and development of sunflowers, the following maintenance measures must be implemented:
Breaking of the cover – due to heavy rains, it is possible to create a cover that can harm the sunflower in the period from sowing to emergence, preventing uniform emergence. It is carried out with a rotary hoe or harrows.
Cultivation – in heavier soils, two cultivations are required. The first is carried out in the phase of 3-4 pairs of leaves at a depth of 8-10 cm, and the second at 10-12 cm. On lighter soils, only the second cultivation is done when the sunflower reaches 40-50 cm in height, while on fertile soils, cultivation is not necessary.
Weed protection – a combination of several herbicides is used, which increases the spectrum of action. Most herbicides are applied after sowing and before emergence, and after emergence, only one preparation (Pledge 50 WP) is used to control broadleaf weeds.
Protection against pests – carried out as needed, and the most common are wireworms, aphids and bedbugs. In addition to mandatory tillage before sowing and adequate fertilization, seed treatment, insecticides and aphicids are used in the fight against pests.
Protection against diseases – the greatest damage is caused by pathogenic organisms, so crop rotation, deep plowing of plant residues, selection of resistant varieties, sowing of seeds treated with fungicides and proper spacing and adequate arrangement of plants are used to prevent diseases. It is recommended to treat twice with fungicides; the first is carried out in the phase from the appearance of 4-6 pairs of leaves to the appearance of the head, and the second at the beginning of flowering. In the first treatment, a tractor sprayer with air support is used, and the second should be carried out with a tractor sprayer for treating tall crops, so as not to damage the flowers.
Sunflower harvest
The beginning of the harvest is at the moment of technological maturity, that is, when the synthesis of substances in the seeds has ended, and the moisture content has been reduced to a level that allows for safe storage, which is approximately at the end of August or the beginning of September.
To determine the exact time of the beginning of the harvest, it is necessary to know the characteristics of the individual hybrid and to take an average sample of seeds from the plot, which is evaluated for humidity, which should be 14-16% at the time of the beginning of the harvest. The sunflower heads turn brown and the leaves and stems dry up. At this seed humidity, it is mandatory to dry with active ventilation, which should reduce the humidity to 8%. If harvesting is done at higher humidity, drying is done with warm air.
Harvesting is done with a wheat harvester, with a header change. The number of revolutions in the drum is 600 rpm, at a humidity of 14-16%. If the moisture content of the grain is 10-12%, the number of revolutions is reduced to 450 rpm, and the number of revolutions is reduced to 250 rpm when the moisture content of the grain is 6-7%. With proper adaptation of the harvester, damages and the number of peeled grains are minimal (lower than 1%).
Average seed yields range from 3 to 5 t/ha, and the yield is also calculated in kg of oil/ha (1500 – 2000 kg/ha of crude oil).
Sunflower drying
The final storage of the yield depends on the optimum date for starting the sunflower harvest. It has been proven that seeds must have a moisture content of 8% during storage, otherwise the seeds may spontaneously combust. To prevent this, the seeds must be dried (40°C). Grains that have more than 40% oil spoil easily in excessive air humidity.
Storage
Dried and purified seeds can be stored in cleaned silos, wall, floor and floor warehouses at adequate temperature and air humidity.
Diseases
Due to the delicate structure of the stem and head, in wetter and rainier years, the sunflower is prone to disease attacks. The most common diseases that occur are: Gray spotting of the stem, Flame blight, Brown spotting of sunflowers, Gray rot of sunflowers, Parasitic flowering plants Volovod, Water lily, Plague and Fairy mow.
Gray spotting of the stem
Gray spotting of the stem (Phomopsis) – symptoms are manifested on the stem and leaf in the form of gray spots surrounded by a dark brown border. They cause the leaves to dry from the top to the stem. If the infection occurs early, the plant will die.
For control, two treatments with fungicides are carried out:
First treatment – BAVISTIN (1 kg/ha) or CINEB (4 kg/ha)
Second treatment – BENOMIL + RONILAN (1+1 kg/ha)
Sunflower flame
Sunflower blight (Plasmopara Halsthedii) – can cause seedling decay, local spots and root rot. Infected plants have a stunted appearance, a thickened tree and shortened internodes. A coating of mycelium forms on the back of the leaves. Suppression is carried out by preventive measures of adequate crop rotation, selection of tested and resistant seeds, treatment of seeds with means based on metalaxyl, which achieves 100% protection, but there is a possibility of the appearance of resistant fungi, therefore regular checks are necessary.
Brown spotting of sunflower
Brown spotting of sunflower (Alternaria helianthi) – leaf spotting and anthracnose of the head occur. Damage can be more than 10%, and the only protection measure is crop rotation and healthy seeds.
Sunflower gray rot
Gray rot of sunflower (Botrytis cinerea Pers.) – most often appears during rainy summers, and appears as spotting on the stem that causes decay and a dirty gray coating appears. Preventive measures include avoiding too dense a structure, healthy seeds and a three-year crop rotation.
Parasitic flowering plants
Parasitic flowering plants Orobanche cumana (Orobanche cumana) – parasite 10-15 cm in size, and the main source of infection are seeds that germinate in favorable conditions, therefore it establishes a parasitic relationship with the first plant that can be a source of nutrients. The plants remain small and form fewer seeds, and the head remains sterile. Cultivation of resistant varieties, crop rotation (10 years) and healthy seeds are the most effective methods of control. As for chemical protection measures, herbicides based on glyphosate are used.
Fairy’s scythe
Fairy grass (Cuscuta spp.) – initially appears as a weed, from which it switches to sunflower, around which a tree is formed with white or pink flowers that then cocoon seeds that spread the parasite. Due to the attack of this disease, the plant suffers morphological, physiological and anatomical damage. Herbicides are used for control.
Pests
The most common pests that cause damage are: Aphids, Wireworms and Polish bugs.
Owls and corn moth may also appear, but they do not cause significant damage. Birds that feed on ripe seeds can also be a problem, so the greatest risk of damage is right before harvest.
Aphids
Black turnip and plum aphid are the most common. When the flower head appears, they settle under the leaves that cover it. Suppression should begin when 20-30% of infected plants are observed at the edges of the belt. The arrival of lice is followed by the so-called Merick pots, and 100-200 plants are monitored on the edge zone. Chemical control is carried out with organophosphorus insecticides.
Cable cars
Wireworms (Elateridae) – the biggest damage is caused by larvae on young sunflower crops, which were thinned after the attack and local oases of stunted plants are created. Agrotechnical and chemical measures are used for control. The primary agrotechnical measures are soil cultivation, followed by crop rotation, pre-sowing, time and method of sowing, fertilization, etc., and insecticides are used for chemical treatment of cable plants.
Polish bed bug
Field bug (Lygus rugulipennis) – during flowering and seed maturation, they cause the greatest damage, which directly reduces oil content, grain weight and seed germination. It is necessary to monitor the number of pests in order to determine the time and method of treatment, but it is most often carried out during the beginning of flowering.
The use of sunflowers
Sunflower cultivation is increasing with the growth of the world’s population and is the main crop for oil production. In addition to its high oil content, sunflower is also used as a protein crop. Every part of the plant is usable, so it has a wide range of applications. The most important product is oil, and we grow hybrids with 45-53% oil in the seeds. In order to improve the quality, hybrids are being developed that have an oleic type of oil (the oleic acid content is greater than 80%), which are similar in quality to olive oil. Protein meal is obtained from sunflower protein for animal feed, but the development of technology enables the production of protein flour, isolate (90% protein) and concentrate (70% protein) for human consumption, most often in the production of special bakery products.
In addition to protein and oil crops, sunflower is also a honey-bearing plant that strongly attracts bees, and in the flowering phase they produce up to 40 kg/ha of nectar and up to 80 kg/ha of pollen powder. Sunflower stalks are rich in potassium, so sunflower ash can be used as fertilizer.
Sunflower heads are extremely nutritious, which is confirmed by the fact that by threshing the flowers on 1 ha, which can be used in livestock feed immediately after, up to 80 kg of meat can be obtained. Sunflower can also be used as green mass or silage. Sunflower seeds can also be used as fuel or raw material in the production of livestock yeast.
Cookery
In addition to sunflower oil, seeds are of great importance in cooking. They are used in a variety of ways, from dried seeds that can be used as a substitute for nuts to butter. They can be used in vegetarian dishes and in combination with tuna and salmon. Roasted seeds can be placed in beaten eggs before making scrambled eggs, which achieves a fuller flavor. They are also used in the production of various bakery products, scones and cakes.
Medicine
In addition to the high content of oil and protein, sunflower contains a high percentage of fiber, minerals and vitamins, especially vitamin E. Research has shown that consumption of seeds lowers cholesterol levels in the blood, maintains normal kidney, liver and skin function.
Cold pressing produces unrefined oil in which high-value ingredients remain (vitamins A, E, B1, B2, B6, D, magnesium, iron, phosphorus, selenium, calcium, zinc). Selenium and vitamin E help to cleanse the body of free radicals. The use of this oil reduces headaches, vision and hearing disorders, inflammation of the eyes, various diseases of the respiratory organs, diseases of the intestines, heart, kidneys, lungs, skin diseases, depression and chronic fatigue.
Sunflower petals are used in alternative medicine to prepare tinctures and teas. Tea helps to lower the temperature, while the tincture diluted with water is used to gargle with inflammation.
Interesting things
3,000 years ago, the sunflower was an essential food item. It was brought to Europe by the Spanish after the conquest of the American continent in 1504. They started growing sunflowers in the botanical gardens in Madrid, and it quickly spread throughout Europe.
It was not until 1830, when oil was extracted from the seeds for the first time in Russia, that it was discovered that the sunflower is not just a decorative plant. Since then, Russia has been the leading country in the production of sunflower oil. It began to be cultivated in European countries in the 20th century, and today, of the total production of all oilseeds, sunflower occupies 90 – 95%.
Sunflower petals were used to make yellow paint.
The seeds in the head have a perfect arrangement, and according to the mathematical model (Vogel model for n=1) it is possible to calculate the maximum number of seeds in a small space.
Conducted research has proven that sunflower cleans soil contaminated with lead and radioactive substances (90%), so sunflower fields were sown in Ukraine after the Chernobyl disaster. Sunflowers were also sown in Fukushima, in areas within a radius of 30 km around the nuclear power plant.
In the past, it was a symbol of light and fertility, and in the 15th century, Aztec priestesses adorned themselves with sunflowers.
Although they have no similarities in appearance, one of the closest relatives of the sunflower is the chicory.
Photo: Uschi_Du/Pixabay