Sunflower

Last updated: June 27, 2025

Sunflower (Helianthus sp.) is the main oilseed crop in Russia.

Economic importance

The oil content in modern zoned sunflower varieties is 50-52 (56)% fat by dry matter of seeds.

Sunflower oil is semidrying and is distinguished by high flavor qualities. It is used directly for food purposes, and also for producing margarine, in canning, baking, confectionery, and other sectors of the food industry.

The main fatty acids of sunflower oil are linoleic and oleic acids. The linoleic acid content in the oil of modern sunflower varieties is 55-60% of the total fatty acids, and oleic acid is 30-35%. Varieties with different ratios of these acids have been developed. For example, the oleic acid content in the oil of the variety Pervenets, developed by the VNII of Oil Crops, is 75-80%, and linoleic acid is 12-17%. In its qualities, the sunflower oil of this variety is not inferior to olive oil.

Sunflower oil also contains phosphatides, vitamins A, D, E, K, and other substances useful for humans.

Lower-grade sunflower oil is used for making soap, varnishes and paints, stearin, linoleum, films, waterproof fabrics, electrical fittings, etc.

The waste products from processing seeds into oil — cake, formed during the press method of oil production, and meal (or cake flour), during the extraction method — are valuable feed for agricultural animals with a high protein content, which contains a large amount of essential amino acids. Waste accounts for 33-35% of the seed mass.

1 kg of meal corresponds to 1.02 feed units and contains 363 g of digestible protein. 1 kg of cake corresponds to 1.09 feed units and contains 226 g of digestible protein. The fat content in the waste ranges from 1 to 7%, and protein from 33 to 35% (Kolomeichenko). According to other data, cake contains 8-10% fat, 36-40% protein, and 20% carbohydrates. Meal contains 1-3% fat (Niklyaev). In phosphorus and calcium content, cake and meal surpass cereal plants.

Threshed sunflower heads also serve as feed for animals. The yield of dry heads reaches 56-60% of the seed mass. 1 kg of flour from dried heads corresponds to 0.8 feed units and contains 38-43 g of protein.

The hulls of sunflower achenes are valuable raw material for the production of hexose and pentose sugar. Hexose sugar is used for producing ethyl alcohol and fodder yeast. Pentose sugar is used to obtain furfural, which is used in the production of plastics, artificial fiber, unbreakable glass, and other chemical materials. The hull yield of modern sunflower varieties reaches 18-20% of the seed mass.

The green mass of sunflower, cut before the budding phase, is used as feed for cattle. The feed qualities of the green mass are average. 100 kg of green mass cut at the beginning of flowering corresponds to 12 feed units, contains 1 kg of digestible protein and 3.5 g of carotene.

Tall (special) sunflower varieties, cut in the budding-flowering phase, in pure form or in mixtures with other fodder grasses (pea, vetch, faba beans, oats, etc.), are used for preparing silage. Sunflower silage is not inferior in nutritional value to silage from the stems and leaves of corn. Usually, sunflower for silage is used in regions where soil and climatic conditions do not allow corn to be used for the same purposes. As a silage crop, it is used mainly in the Non-Chernozem Zone and Western Siberia.

The yellow petals of the heads are used in pharmacology.

It is a good honey plant, since it is the basis of the bee forage conveyor for a long period.

Plant residues in chopped form after seed harvest can serve as a good organic fertilizer.

History

The homeland of sunflower is considered to be the dry prairies of the southwest (or south) of North America, where wild representatives of the genus Helianthus, to which the modern cultivated sunflower belongs, are widespread (Vavilov, Kolomeichenko). According to other data, the homeland is North and South America from California to Bolivia (Niklyaev).

It was brought to Europe by the Spaniards in 1510 as an ornamental plant.

Sunflower was brought to Russia from Holland in the 18th century as an ornamental plant and for obtaining edible seeds, which were consumed as a delicacy instead of nuts.

The first information about the possibility of obtaining oil from seeds dates to 1769. The idea of practical cultivation of sunflower as an agricultural crop and the use of its seeds for oil production belongs to the serf peasant D. S. Bokarev of the settlement Alekseevka, Biryuchensk uyezd, Voronezh province (Belgorod oblast). As early as 1829 (Vavilov, Niklyaev; according to other data, 1835, Kolomeichenko), with the help of a hand press, he was the first in the world to obtain oil from sunflower seeds grown in his own garden. In 1833, the first horse-driven oil mill was built in the same settlement, and in 1865, the first oil factory.

Later, sunflower crops spread to Voronezh and Saratov provinces, Ukraine, the North Caucasus, and Siberia.

In 1860, work on breeding oilseed varieties began in the Russian Empire. A great role in breeding work on cultivated sunflower (Helianthus cultus Wenzl) was played by outstanding Russian breeders E. M. Plachek, L. A. Zhdanov (Hero of Socialist Labor, academician of the VASKhNIL), V. S. Pustovoit (twice Hero of Socialist Labor, academician), V. I. Shcherbina, K. I. Prokhorov, and others. It is precisely in Russia that there is the greatest biodiversity of forms, varieties, and hybrids of cultivated sunflower. Local varieties cultivated in pre-revolutionary times had low oil content (28-30%) and high hull content (43-44%). Modern varieties contain up to 45-50% oil, and their hull content does not exceed 22-25%.

During the Soviet period, a great contribution to the creation of highly productive varieties resistant to broomrape and sunflower moth was made by the All-Union Research Institute of Oil Crops named after V. S. Pustovoit (VNIIMK), as well as the experimental stations of this institute: Donskaya (Ukrainian SSR), Armavir, and Belgorod.

In the second half of the 20th century, interest in this crop as an oilseed plant noticeably increased. The world area sown to sunflower in 1984 was 13.4 million ha. By country, as of 1984, the areas occupied by crops were:

USSR — 4.5 million ha;
USA — 1.5 million ha;
Argentina — 1.9 million ha;
Hungary — 0.3 million ha;
India — 0.67 million ha;
Bulgaria — 0.3 million ha.

In the USSR, sunflower as an oilseed crop was grown in the RSFSR — 2.5 million ha (55%), in Ukraine — 1.7 million ha (38%), in Moldova — 170 thousand ha (4%), in Kazakhstan — 100 thousand ha (2%), in Georgia — 15 thousand ha. By 1990, it was planned to bring the gross sunflower harvest to 7.4-7.5 million t.

Chemical composition

Chemical composition of green mass cut in the phase of mass flowering:

water — 65-70%;
carbohydrates — 17%;
protein — 2.5%;
fats — 0.8%.

The green mass also contains a large amount of calcium and phosphorus.

The chemical composition of sunflower silage includes:

water — 73.4-83.5%;
protein — 1.8-3.1%;
fats — 0.6-1.9%;
fiber — 4.4-8.8%;
nitrogen-free extractives — 5.8-11.1%;
ash — 2.3-3.3%, including 0.7% calcium.

The ash of sunflower stems contains about 4% P₂O₅ and up to 36% K₂O. Therefore, it can serve as a fertilizer and for obtaining potash (potassium carbonate).

Cultivation areas and yield

By the end of the 20th century, the world sown area occupied by sunflower was about 21 million ha, or 12% of the entire sown area occupied by oilseed crops.

The world gross harvest of seeds was about 25 million t, or 10% of the total harvest of oilseeds. The yield was 1.2 t/ha, or 0.3 t/ha less than the average for oilseed crops.

In Russia, about 80% of all areas occupied by sunflower are in the North Caucasus (Rostov oblast), the Central Chernozem Zone, and the Middle and Lower Volga region. Significantly smaller areas are in the Urals and Western Siberia. The territories of Eastern Siberia and Altai were gradually being developed.

For 2001-2005, the area occupied by sunflower crops in Russia was 4.5 million ha, or 83% of the entire sown area of oilseed crops. The gross harvest of oilseeds reached 4 million t, or 85% of total production.

The average seed yield was (as of 1984) 1.2-1.4 t/ha. The highest yields are traditionally obtained in the Kuban. Record yields, on average 2.7-2.9 t/ha, were obtained in Soviet times in many farms, for example, in the collective farm “Kuban”, the collective farm named after Krupskaya of Ust-Labinsk district, the collective farm “Pobeda” of Dinsk district, and others. According to data from the early 2000s, the average yield was 0.94 t/ha, or approximately the same as the average for oilseed crops (0.95 t/ha). The maximum yield of the best hybrids at variety-testing plots and under excellent growing conditions reaches 2-3 t/ha. High yields of 2-2.5 t/ha were obtained in Voronezh, Tambov, Lipetsk, and Belgorod oblasts; in Rostov oblast and Krasnodar krai — 2.7-3 t/ha.

The advancement of sunflower crops to the north and east of Russia, primarily to the south of the Non-Chernozem Zone, Eastern Siberia, and the Far East, is facilitated by the development of earlier hybrids and varieties, as well as the development of new agrotechnological methods.

Botanical description

Sunflower belongs to the family Asteraceae (Asteraceae).

The species of sunflower established by Linnaeus, Helianthus annus L., is currently considered a collective species. It is divided into two independent species:

Helianthus cultus Wenzl. — cultivated sunflower, which is also divided into two subspecies:
ssp. sativus Wenzl. — cultivated sown sunflower;
ssp. ornamentalis Wenzl. — cultivated ornamental sunflower;
Helianthus ruderalis Wenzl. — wild sunflower.

Cultivated sown sunflower is an annual plant.

Root

The root is a taproot, penetrates the soil to a depth of 2-4 m and spreads laterally by 100-120 cm.

Stem

The stem is erect, woody, has a loose pith, and is unbranched.

Plant height is from 0.7 to 2.5 m; in silage varieties it reaches 3-4 m.

The height of oilseed varieties and hybrids is from 1.5 to 2.5 m, and of confectionery varieties — 2-4 m.

Leaves

The leaves are large, densely pubescent, ovate-cordate, with a pointed tip and serrate edges, on long petioles.

The lower leaves (3-5 pairs) are arranged oppositely, the rest alternately.

One plant of early varieties forms 15-25 leaves, and late varieties — 30-35. Confectionery varieties and hybrids are more leafy.

Inflorescence

The inflorescence is a terminal head in the form of a flat, convex, or concave disk, which is surrounded by an involucre of several rows of leaflets. The head diameter of oilseed varieties is (8) 10-20 (25) cm, and of confectionery varieties — 30-40 (45) cm. At the base of the head is the receptacle, on which ray florets are located along the edges, and tubular florets inside.

The ray florets are sterile, large, orange-yellow, and sometimes have an underdeveloped pistil. These flowers attract insects, which is of great importance for pollination. The tubular florets are bisexual and occupy almost the entire receptacle. One head contains from 600 to 1200 tubular florets.

Each flower has a pistil with an inferior unilocular ovary and a style, as well as a corolla with fused petals and five teeth. The corollas range from light yellow to dark orange.

The flowers in the flowering phase open gradually from the periphery to the center of the head.

There are five stamens, the filaments are free, and the anthers are fused.

It is a cross-pollinated plant. Usually under natural conditions, some flowers remain unfertilized, which leads to empty seeds. To reduce empty seeds, beehives with bees are brought to the fields during flowering.

Fruit

The fruit is a compressed-ovoid achene, with four indistinct edges. It consists of the seed — the kernel with a thin seed coat — and a leathery, dense, hard pericarp (skin or hull), not fused with the kernel.

The pericarp has an epidermis, beneath which cork tissue is located, and deeper than it there are several layers of lignified sclerenchyma cells. The upper layers of sclerenchyma in armored varieties are formed by a black, water-, acid-, and alkali-insoluble substance (phytomelanin), protecting the seeds from sunflower moth.

The hull can be white, gray, black, and also have a striped or non-striped texture. The hull content of achenes, that is, the mass of the hull in relation to the mass of the seed, varies from 22 to 46% (56%). The most valuable varieties are sunflower varieties with low hull content.

The mass of 1000 seeds is 40-125 (170) g.

Seeds

The seed (kernel) includes the embryo and a thin seed coat.

The embryo consists of a radicle, a bud, and two cotyledons. During germination, the cotyledons are brought to the soil surface.

Ecological requirements

Sunflower belongs to plants of a continental climate. The homeland of its wild forms is the dry prairies of North America, and cultivated forms were formed under the conditions of the steppe zone of the European part of Russia and the former USSR, where high temperatures and low air humidity in summer are characteristic. At the same time, sunflower is distinguished by high ecological plasticity.

Temperature requirements

Germination of sunflower seeds begins at a temperature of 4-6 °C (according to other data, 4-5 °C). An increase in temperature accelerates the appearance of seedlings. At a temperature of 8-10 °C, seedlings appear 15-20 days after sowing; at 15-16 °C — after 9-10 days; and at 20 °C — after 6-8 days. The optimal germination temperature is 12-15 °C.

The sum of active temperatures for the period from sowing to emergence is 140-160 °C.

Swollen sunflower seeds can easily tolerate frosts down to -10 °C, and swollen seeds down to -13 °C. Seedlings withstand short-term frosts down to -5…-8 °C.

After emergence, the heat requirements of plants increase. In the flowering phase and the subsequent period, the optimal temperature for sunflower is 25-27 °C (Vavilov; according to other data, 20-25 °C, Niklyaev). Temperatures above 30 °C have a depressing effect.

In the flowering phase, sunflower plants are sensitive to low temperatures. Frosts of -1…-2 °C during this period lead to severe damage and complete death of flowers.

Damage to the growing point from frost leads to strong branching of plants; therefore, for fodder purposes, sunflower can be sown at the earliest dates.

It is very sensitive to autumn cooling and does not withstand even light frosts on the soil.

The sum of active temperatures required for ripening early varieties is 1600-1800 °C; for mid-season and late varieties — 2000-3000 °C.

Moisture requirements

Sunflower places rather high demands on moisture. The water consumption of one plant during the growing season exceeds 200 liters. The transpiration coefficient is 470-570. To form 100 kg of seeds, plants use 140-180 t of water, or 3000-6000 t per ha.

Thanks to the root system penetrating the soil to a depth of more than 3 m, sunflower is drought-resistant. Plants are able to use moisture from deep soil layers that is inaccessible to many other annual plants.

Thanks to the pubescence of stems and leaves, as well as the adaptation of stomata to constant transpiration, the resistance of sunflower to drought and heat is increased, especially before flowering begins.

According to data from the Research Institute of Agriculture of the South-East, sunflower uses moisture unevenly:

during the period from emergence to head formation, sunflower consumes (22) 23% of moisture from total consumption during the growing season;
from head formation to (the end of) flowering — 60%, which is the critical period in terms of moisture requirement (Vavilov, Kolomeichenko; according to other data, 40-50%, Nikitin);
from flowering to ripening — 17 (18)%.

A lack of moisture in the soil during the critical period is the cause of “flower abortion” and empty seeds in the center of the heads, and a sharp decrease in yield.

At the beginning of the growing season, sunflower plants use moisture from the upper soil layers, whereas after head formation, water consumption occurs mainly from a depth of more than 50 cm.

During severe drought by the beginning of flowering, a large number of initiated flowers, primarily in the central part of the head, do not open. At the same time, the mass of both individual achenes and the total mass of seeds from one plant significantly decreases, which leads to a decrease in sunflower yield. For this reason, when growing sunflower in arid regions, moisture accumulation is of great importance: snow and meltwater retention, irrigation, and other methods contributing to improving the water regime.

Soil requirements

In Russia, most sunflower crops are placed on leached, thick, and ordinary southern chernozems, as well as on chestnut soils.

It prefers sandy loam and loamy chernozems, also chestnut, gray forest (sandy loam and loamy), and podzolized soils.

The optimal interval for plant growth is pH 6.0-6.8 (7).

Sunflower tolerates heavy clay, (light) sandy, acid, strongly saline (solonetzic), and swampy soils poorly. It is considered less demanding on soils than corn.

Light requirements

Sunflower belongs to light-loving plants.

Shading and cloudy weather lead to a delay in plant growth and development or to their elongation; leaves form small, which leads to a decrease in yield.

Sunflower is a short-day plant. Under conditions of longer daylight, the growth and accumulation of green mass of plants increases, but flowering and ripening are delayed. Therefore, when moving north, its growing season increases, productivity in green mass increases, but seed ripening is delayed, and their yield decreases.

Nutrient requirements

The need of sunflower for nutrients is significantly greater than that of cereal crops. To form 100 kg of seeds, sunflower, according to numerous experimental data, on average consumes 5-6 kg of nitrogen, 2-2.5 kg of phosphorus, and 10-12 (16) kg of potassium. The N : P₂O₅ : K₂O ratio is 3 : 1 : 5. The amount of nutrients consumed depends on growing conditions and yield level.

The supply of nutrients to plants during the growing season is uneven. The greatest nitrogen consumption occurs in the period from the beginning of head formation to the end of flowering; phosphorus — from emergence to flowering; potassium — from head formation to ripening.

The initial period of plant development is critical in phosphorus consumption.

During sunflower ripening, the main mass of consumed nitrogen and phosphorus accumulates in the seeds, whereas only about 10% of potassium accumulates there; the remaining 90% accumulates in vegetative organs.

By the time of flowering, sunflower plants use up to 60% of nitrogen, up to 80% of phosphorus, and up to 90% of potassium from the total removal from the soil during the entire growing season.

Vegetation

The vegetation of sunflower plants according to morphological characteristics is divided into the following main phases (Vavilov):

emergence;
beginning of head formation;
flowering;
ripening.

VNIIMK recommends distinguishing the following development phases by morphological characteristics:

emergence;
leaf formation, that is, from emergence to the formation of 4-5 pairs of true leaves;
differentiation, or from 4-5 pairs to 9-10 pairs of leaves;
active growth, or from 9-10 pairs of leaves to the beginning of flowering;
flowering;
formation and filling of seeds;
ripening.

Another variant of grouping sunflower growing-season periods (Kolomeichenko):

seed germination;
emergence;
first and second pairs of leaves;
third and fourth pairs of leaves;
budding;
flowering;
growth and filling of achenes;
ripening;
full ripeness.

Table. Growth and development phases, stages of organogenesis, and formation of sunflower productivity elements (Department of Plant Growing, Don Agrarian University (Alabushev et al., 2001).

Phase	Stages of organogenesis and leading processes	Formation of productivity elements
Emergence	I — growth cone undifferentiated, weakly visible, flat in shape	Number of plants per area
1st pair of leaves 2nd pair of leaves 3rd pair of leaves	II — growth cone enlarges, stem and leaf primordia form III — receptacle formation, growth of lower leaves IV — initiation of flower tubercles	Plant habit (height, branching)
Inflorescence formation	V — formation of cover and generative flower organs VI — pollen forms in anthers, embryo sac in ovary VII — growth of flowers, stamen filaments	Number of flowers in inflorescence
Flowering	VIII — corolla development, involucre of head unfolds, anther emerges from corolla IX — flowering and fertilization	Number of achenes in head
Achene formation	X — achene formation (growth in length)	Achene size
Achene filling	XI — deposition of storage substances, oil accumulation	Achene mass
Achene ripening	XII — conversion of nutrients into storage substances, increase in oil content	Achene mass

Table. Sunflower growth and development phases (BBCH code) (Western Europe, Schpaar D.).

	Microphases
0. Germination	00 Dry seed. 01 Beginning of swelling. 03 End of swelling. 05 Emergence of the embryonic root from the seed. 06 Embryonic root elongated, formation of root hairs. 07 Hypocotyl and cotyledons have broken through the seed coat. 08 Hypocotyl breaks through the soil surface. 09 Emergence (cotyledons appear on the soil surface).
1. Leaf development, main shoot (when clearly visible growth in length (stretched internodes) begins, switch to macrophase codes)	10 Cotyledons fully open. 12 Two true leaves (1 pair) open. 14 Four true leaves (2 pairs). 15 Five true leaves. 16 Six true leaves. 17 Seven true leaves. 18 Eight true leaves. 19 Nine true leaves.
2.	—
3. Stem elongation	30 Beginning of stem elongation. 31 First stretched internode visible. 32 Second stretched internode visible. 33 Third stretched internode visible. 3… Microphases continuing to… 39 Nine or more stretched internodes visible.
4.	—
5. Inflorescence emergence	51 Inflorescence bud visible between young leaves (star microphase). 53 Inflorescence separates from upper leaves, bracts clearly distinguishable from true leaves. 55 Inflorescence separated from the upper true leaf. 57 Inflorescence clearly separated from upper true leaves. 59 Inflorescence still closed. Ray florets visible between bracts.
6. Flowering (main shoot)	61 Beginning of flowering. Ray florets positioned vertically on the head, tubular florets visible in the outer third. 63 Tubular florets in the outer part of the head flowering, stamens and stigmas free. 65 Full flowering. Tubular florets in the middle part of the head flowering, stamens and stigmas free. 67 Completion of flowering. Tubular florets in the inner part of the head flowering, stamens and stigmas free. 69 End of flowering. All tubular florets have flowered. Fruit set visible in the outer and middle parts of the head. Ray florets dried or fallen.
7. Fruit development	71 Seeds at the edge of the head are gray, species- or variety-typical size 73 Seeds in the outer part of the head are gray, species- or variety-typical size 75 Seeds in the middle part of the head are gray, species- or variety-typical size 79 Seeds in the inner part of the head are gray, species- or variety-typical size
8. Ripening of fruits and seeds	80 Beginning of ripening. Seeds at the edge of the head black, seed coat hard, back side still green. 81 Seeds in the outer part of the head black and hard, back side still green. 83 “Lemon” ripeness (back side of head yellowish-green). Bracts still green. Seed moisture about 50%. 85 Continuing seed ripening. Seeds in the middle part of the head black. Bract edges brown. Back side of head yellow. Seed moisture about 40%. 87 Physiological ripeness. Back side of head yellow. Bracts on 75% of leaf surface brown. Seed moisture about 15%. 89 Full ripeness. Seeds in the inner part of the head black, bracts brown. Back side of head brown. Seed moisture about 15%.
9. Senescence	92 End of full ripeness (overripe). Seed moisture about 10% 97 Plant dead 99 Harvested products (seeds).

The duration of interphase periods for the most widespread group of mid-season varieties is (Vavilov):

from sowing to emergence — 14-16 days;
from emergence to the beginning of head formation — 37-43 days;
from the beginning of head formation to flowering — 27-30 days (according to other data, 50-60 days after emergence, Kolomeichenko);
from flowering to ripening — 44-50 days.

The total duration of vegetation for this group of sunflower varieties is 120-140 days. Depending on the variety or hybrid and growing conditions, achene ripening may occur (70) 80-120 (140) days after emergence.

In the first period of their development (2-3 pairs of leaves), sunflower plants develop relatively slowly. At this time they are easily suppressed by weeds. However, then growth accelerates and reaches its maximum, which is 3-5 cm per day, in the period from head formation to the beginning of flowering. In the flowering phase, growth in height slows and by the end of flowering stops completely.

The beginning of head formation in early sunflower varieties under the conditions of the South-East of Russia occurs at 2 pairs of leaves; in mid-season varieties — at 3-5 pairs. Head initiation in mid-season varieties begins under the conditions of Krasnodar krai at 5 pairs of leaves.

Flowering of one head lasts 8-10 days, and growth continues until it turns yellow. The head grows most intensively for 8-10 days after the end of flowering. Achene filling lasts 32-42 days from the time of fertilization.

Simultaneously with plant growth in height and head formation, dry substances begin to accumulate. During this period this process is slow, and by the beginning of head formation sunflower accumulates only 15% of dry substances. By the beginning of the flowering phase, the amount of dry matter in the plant reaches 50%, and it continues to increase until the beginning of achene filling, but is also mainly spent on head formation.

Physiological after-ripening of achenes after harvest can be 10-50 days.

Crop rotation

In the main areas of sunflower cultivation, the most widespread predecessors are winter cereal crops, especially those following clean or occupied fallow. With such a crop rotation variant, good conditions of nutrient and water regime are created for sunflower plants. Good predecessors for sunflower include corn, grain legumes, as well as spring cereal crops (wheat, barley) and flax.

In the Urals and Siberia, the best predecessors of sunflower are spring cereals.

Thanks to the deep-penetrating root system, sunflower plants are able to effectively use moisture from soil layers of 100-200 cm and even 200-300 cm, primarily in the second half of the growing season. Seed yield often depends on the presence of moisture in these layers. Therefore, in crop rotations, sunflower is not placed after crops with a powerful root system that dries out the lower horizons, such as alfalfa, sugar beet, Sudan grass. In regions with insufficient moisture, where these crops are present in crop rotations, sunflower should be placed only 3-4 years after one of them, and its return to the previous place is allowed no earlier than after 8-10 years. Earlier return leads to the spread of broomrape, diseases, and pests. From these conditions it is obvious that a crop rotation including sunflower, sugar beet, and perennial grasses should be at least a 10-12-field rotation and have a long rotation cycle.

Undesirable predecessors of sunflower in crop rotations also include pea, soybean, bean, and rapeseed, which share diseases with sunflower (sclerotinia, gray mold, etc.).

Sunflower is heavily affected by downy mildew and broomrape (Orobanche sp.), therefore its return to the previous place in crop rotation is allowed no earlier than after 8-10 years.

For silage varieties and hybrids of sunflower, crops that leave fields free of weeds, as well as loose and nutrient-enriched soils, are suitable, for example, winter and spring cereal crops following a layer of perennial grasses, potato, fodder root crops. It is also possible to grow it as an aftercut crop — after winter crops for green feed or annual grasses. Repeated return in this case is possible after 5-7 years.

Sunflower itself serves as a good predecessor for spring wheat, oats, barley, and other spring cereal crops. However, they are often infested by volunteer sunflower. In the south of the Kuban — for winter crops.

An important feature of sunflower as a predecessor in crop rotations is volunteer plants, that is, sunflower seeds that fell during harvest in autumn. After overwintering, these seeds produce seedlings and infest the crops of subsequent crops. Failure to observe optimal harvesting dates and large losses of sunflower seeds lead to an increase in volunteer plants. Volunteer plants are most harmful in spring cereal crops following sunflower. Deep autumn plowing is advisable for controlling volunteer plants.

Sunflower is one of the main crops used in backstage strips, which are used in steppe regions for snow accumulation and protection from wind erosion.

Fertilizer system

The fertilizer system for sunflower includes the main fertilizer during autumn tillage, as well as row fertilizer at sowing.

Organic and mineral fertilizers are used as the main fertilizer. According to long-term experiments of VNIIMK, applying manure in autumn at a rate of 15-20 t/ha is effective for all main zones of sunflower cultivation. The increase in seed yield reaches 220-500 kg/ha. Sunflower is also responsive to the aftereffect of manure. When manure is applied to the preceding crop, seed yield increases by 2-3 c/ha. For chernozem soils, applying manure at a rate of 20-40 t/ha gives an increase in sunflower seeds of 0.2-0.5 t/ha.

For applying manure, spreaders such as RUN-15B are used.

According to generalized data from experimental institutions, sunflower responds differently to the application of mineral fertilizers during autumn plowing (NPK at 45-60 kg/ha) in different zones (table).

Table. Response of sunflower to mineral fertilizers in various zones of its cultivation.

Zone	Chernozem difference	Seed yield without fertilizers, t/ha	Increase in seed yield, t/ha
Zone	Chernozem difference	Seed yield without fertilizers, t/ha	P	NP	NPK
North Caucasus	Leached	2.27	+0.21	+0.39	+0.21
Central Chernozem	Ordinary	1.38	+0.10	+0.23	+0.26
Ukraine	Southern	1.41	+0.16	+0.28	+0.21

The greatest increase in yield (0.23-0.39 t/ha) is provided by the application of nitrogen-phosphorus fertilizer. The effect of applying only phosphorus fertilizer is smaller and amounts to 0.10-0.21 t/ha. The application of potassium fertilizer is inadvisable, even in combination with nitrogen-phosphorus fertilizer, since it not only does not lead to an increase, but sometimes even reduces yield.

Application rates and fertilizer efficiency are determined by zonal characteristics. For example, in the steppe regions of Ukraine, N_30-60P_60-90 is optimal. For the forest-steppe zone — N_45-60, P_45-60, K_45-60 (Vavilov). According to other data (Kolomeichenko), for the steppe and forest-steppe zones on chernozem and dark chestnut soils, it is recommended to apply N₄₀P₆₀ (since these soils are sufficiently supplied with potassium). On sandy loam soils with low potassium content, K_40-60 is applied. Also (Niklyaev), general recommendations — N_30-60P_45-90K_45-60.

The rates of mineral fertilizer application are adjusted taking into account the planned yield and agrochemical analysis data.

Potassium fertilizers for sunflower are usually applied on soils poor in potassium.

Sunflower yield increases with the combined application of organic and mineral fertilizers.

For applying fertilizers, spreaders such as 1-RMG-4 or YuMZ-6AL are used.

Row fertilizer for sunflower, especially phosphorus fertilizers, gives a yield increase and increases the oil content of seeds. At sowing, fertilizer is applied at a distance of 6-10 cm from the row to a depth of 10-12 cm at a rate of N₁₀P_10-15 in two or one band. For this, converted fertilizer-sowing apparatuses of seeders SPCh-8M or SPCh-6MF can be used.

Top dressing of sunflower during the growing season is usually considered ineffective (Kolomeichenko). According to other data, sunflower responds very well to top dressing (Niklyaev). For these purposes, up to 1/3-1/4 of all fertilizers is used. Sometimes top dressing is carried out in two stages: at the first stage, fertilizers are incorporated with cultivators-plant feeders to a depth of 7-8 cm; at the second — to 10-12 cm. If possible, it is better to use liquid complex fertilizers N₂₀P₃₀.

Soil tillage system

Primary tillage

Primary tillage for sunflower differs for different natural zones. Depending on conditions, one of the techniques of autumn soil preparation can be used: ordinary autumn tillage, semi-fallow, and improved autumn tillage. In all cases, before plowing, stubble disking is carried out with disk implements to a depth of 6-8 cm (Vavilov; according to other recommendations, 5-7 or 8-12 cm, Niklyaev).

Ordinary autumn tillage consists of stubble disking followed by autumn plowing to a depth of 20-22 cm for light and weed-free soils, or 25-30 cm for heavy and perennial-weed-infested soils. It is used in the northern and eastern regions of sunflower cultivation, such as Siberia, Kazakhstan, the north of the Central Chernozem Zone, and the Volga region.

Semi-fallow tillage differs from ordinary autumn tillage in that after early plowing, the soil is treated like black fallow. It is used in regions with a long, at least one month, warm autumn period after harvesting the preceding crop.

Improved autumn tillage consists of stubble disking, after which 2-3 layer-by-layer surface treatments are carried out, and in September-October the main plowing is performed. This technique is widespread in many sunflower cultivation regions, such as the North Caucasus, Ukraine, and Moldova. Layer-by-layer treatment of improved autumn tillage reduces weed infestation by 70-80% and improves the quality of subsequent plowing.

With severe infestation by perennial root-sprouting weeds, for example, thistle, sow thistle, field bindweed, layer-by-layer soil treatment is used. For this, stubble disking is carried out to a depth of 6-8 cm with disk implements; then, after regrowth of root-sprouting weeds, the soil is treated to a depth of 10-12 cm with moldboard plows, heavy disk harrows, or flat cutters. Then, after repeated regrowth, deep autumn plowing is performed to a depth of up to 30-32 cm.

In regions of sufficient moisture in Krasnodar krai and other regions with similar conditions, double layer-by-layer plowing is used. For this, after stubble disking, shallow plowing is carried out to a depth of 14-18 cm, then 2-3 surface treatments, and in October — repeated deep plowing to 27-30 cm. Such soil treatment, including deep plowing, is effective in controlling root-sprouting weeds.

On cultivated chernozems in the absence of perennial weeds, deep plowing (to a depth of 27-30 or 30-32 cm) for sunflower does not give advantages over ordinary plowing (20-22 cm).

In regions subject to wind erosion, to protect soils from removal, moldboardless (flat-cut) tillage is used, which allows preserving most of the crop residues on the soil surface. For this, two shallow treatments are carried out and then autumn deep loosening to 20-25 cm.

Snow retention gives positive results. According to data from the Research Institute of Agriculture of the South-East, thanks to snow retention measures in fields, the increase in sunflower seed yield reaches 0.6 t/ha. In spring, snow compaction can be carried out, and for retaining meltwater — slitting.

Pre-sowing tillage

Pre-sowing soil treatment is determined by the quality of autumn plowing and the condition of the field in spring.

In the presence of wintering weeds and on slaking soils, as well as winter crop volunteers, spring soil treatment for sunflower includes early harrowing with heavy and medium harrows and 1-2 cultivations with simultaneous harrowing and smoothing.

In the case of using industrial cultivation technology, careful leveling of the field surface is necessary, since this affects the quality of herbicide application and sowing.

According to VNIIMK data, carrying out two cultivations of autumn plowing in fields infested with annual weeds and to an insignificant degree with perennial weeds, at an average sowing date, does not have a significant advantage compared to one cultivation. The greatest effectiveness with one pre-sowing cultivation is achieved when the soil warms to 8-12 °C and mass emergence and seedlings of weeds appear.

In the case of autumn flat-cut treatment with stubble left on the soil surface, needle harrows and then cultivators are used for pre-sowing soil preparation.

Pre-sowing treatment is carried out to the depth of seed sowing, that is, 6-8 cm when using standard-size seeds or 5-6 cm for small seeds.

Soil treatment for sunflower silage varieties and hybrids does not differ.

Sowing

Seed preparation

For sowing, sunflower seeds of zoned and promising varieties and hybrids are used.

According to varietal qualities, that is, typicality and armoredness, sunflower seeds are divided into three categories:

Category I — seeds with typicality not less than 99.8%, armoredness not less than 98%;
Category II — seeds with typicality not less than 98%, armoredness not less than 96%;
Category III — seeds with typicality not less than 97%, armoredness not less than 95%.

According to sowing qualities, sunflower seeds are divided into three classes:

Class 1 — seed purity not less than 99%, germination not less than 95%;
Class 2 — seed purity not less than 98%, germination not less than 97%;
Class 3 — seed purity not less than 93%, germination not less than 90%.

Seeds must be well filled.

For sowing, the use of calibrated (uniform) seeds is of great importance. Calibrated seeds allow obtaining more uniform plants in height and vigor, thereby increasing their productivity and reducing harvest losses. Sowing filled and large seeds allows increasing sunflower yield by 0.15-0.3 t/ha. Calibration of seeds is more important with precision sowing in order to avoid further thinning.

Before sowing, to protect seeds from diseases, they are treated with 65% fentiuram at a rate of 3 kg/t of seeds. To prevent infection with downy mildew, treatment with apron (6 kg/t) is carried out.

Insecticides for sunflower seeds include a highly active insecticide — technical gamma-isomer of hexachlorane with a consumption rate of 2-4 kg/t of seeds. Treated seeds are covered with a film-forming composition, that is, they are incrusted. Seeds treated in this way are protected from damage by soil pests, and it is possible to ensure the specified plant stand density.

For seed treatment, the following preparations are permitted (2007):

TMTD, in the forms of wettable powder (800 g/kg), suspension concentrate, etc. — for controlling white and gray mold, seed molding, and peronosporosis;
Aktamyr, etc. — for controlling white and gray mold, seed molding, and peronosporosis;
Maksim, suspension concentrate — for controlling phomopsis, downy mildew, gray, white, dry, and Fusarium rots;
Semafor, etc. — for controlling wireworm.

At high wireworm numbers, insecticides are additionally applied to the soil.

Sowing dates

For the main cultivation regions, sunflower sowing dates fall in early and mid-spring (respectively early and medium sowing dates). There are almost no differences between these dates. Very early and late sowing dates are inadvisable.

On weedy soils, medium dates are more preferable, that is, when the soil warms to 8-12 °C at the depth of seed placement. By this time, seedlings and sprouts of early weed plants appear on the soil surface, which are destroyed during pre-sowing cultivation.

Early sowing dates occur when the soil warms to 5-7 °C. At the same time, the physical ripeness of the soil may not yet have occurred, and seedlings of early weeds are often absent.

Seeds of high-oil varieties are characterized by higher heat requirements, therefore they should be sown when the soil warms to 8-10 °C at the depth of seed placement (8-10 cm). Early sowing dates for such varieties and hybrids lead to a long time for their germination and partial loss of germination, which causes thinning of seedlings.

Sowing at late dates, that is, when the soil warms to 14-16 °C and more, leads to a decrease in sunflower yield in all cultivation regions.

In the arid regions of the South-East of Russia, where a lack of moisture reserves in the soil is characteristic, early sowing dates are optimal and give the best results.

In the forest-steppe part of the Central Chernozem Zone, sunflower is also recommended to be sown at early dates. Delaying sowing dates in these regions, for example, to wait for the emergence of early weeds with their subsequent destruction by pre-sowing cultivation, leads to a delay in sunflower seed ripening.

Under the conditions of the Southern Urals and Western Siberia, sunflower sowing is carried out at medium dates, which contributes to a sharp increase in its yield, whereas early sowing can lead to damage to sunflower seedlings from spring frosts and suppression by weeds.

It should be borne in mind that sunflower seeds with a thick, lignified hull swell very slowly, therefore they are sown at earlier dates.

Sowing is carried out in a short time — over 2-3 days.

When used for fodder purposes, sunflower can be sown at various dates, for example, in early spring simultaneously with early cereal crops, during the sowing of heat-loving crops, or undersown into corn interrows. As an aftercut crop, sunflower is sown after harvesting winter crops for green feed or annual grasses.

Under the conditions of the steppe and forest-steppe zones, it may be advisable to use volunteer oilseed sunflower the following year by overseeding such fields in early spring with oats, barley, vetch, pea, their mixtures, or other crops.

Sowing methods

Sunflower sowing methods can be wide-row, with row spacings of 70 cm (also 45 and 60 cm) or precision.

For sowing, seeders SUPN-8, SUPN-8A, SPCh-6M, or SKPP-12 are used.

The precision sowing method allows relatively achieving the optimal plant nutrition area and such a stand density that ensures maximum seed yield. When determining the optimal plant stand density, one proceeds from the water supply of sunflower. With insufficient moisture reserves in the soil, the stand density is reduced; with sufficient moisture and application of increased fertilizer rates, it is increased.

For obtaining sunflower silage, it is sown in mixtures with other crops, since in pure form it contains little dry matter and protein. Most often, sunflower for these purposes is sown in mixtures with oats, vetch, lupine, leguminous crops, and field pea (pelushka) is more productive than garden pea. All these crops are sown either simultaneously with sunflower sowing, or undersown across the rows or into interrows after inter-row cultivation in the phase of the first pair of true leaves.

Silage varieties and hybrids of sunflower are sown by ordinary row, wide-row, or precision methods.

Mixed sowing of sunflower is carried out by the ordinary row method.

For sowing mixtures, precision, vegetable, and grain seeders are used. In mixed crops, sunflower often does not withstand competition with other crops that are sown by the solid method.

Seeding rates

Experimental institutions have established the following optimal sunflower plant stand densities per 1 ha for various soil and climatic zones of Russia:

European part:

for humid forest-steppe and adjacent steppe regions (thick, leached, and podzolized chernozems) — 40-50 (60) thousand plants per 1 ha, or 30-35 plants per 10 m of row;
semiarid steppe (ordinary chernozems) — 30-40 thousand plants per 1 ha, or 20-30 plants per 10 m of row;
arid steppe (southern chernozems, dark chestnut soils) — 20-30 thousand plants per 1 ha, or 15-20 plants per 10 m of row.

Asian part:

southern forest-steppe (ordinary and rich chernozems of the West Siberian Lowland) — 30-40 thousand plants per 1 ha;
southern chernozems, dark chestnut soils — 20-30 thousand plants per 1 ha.

When using industrial sunflower cultivation technology, the optimal plant stand density is achieved by sowing an established number of seeds per 1 ha, while additional manual thinning of plants is not carried out. Taking into account field germination and plant survival, the specified number of sown viable seeds is, as a rule, 25-30% greater than the optimal number of plants. For example, with a formed plant stand density of 40 thousand per 1 ha, it is necessary to sow 50-52 thousand germinating seeds per 1 ha. To carry out sowing with such density, seeder disks are selected that allow sowing 36-37 seeds per every 10 m of row.

On average, the seeding rate of oilseed varieties and hybrids of sunflower is (5) 6-8 (10) kg/ha, and of silage varieties — 35-40 kg/ha.

For the wide-row sowing method, the seeding rate varies from 10 to 25 kg/ha; for the solid row method — from 20 to 40 kg/ha.

Approximate seeding rates for fodder mixtures with sunflower:

60 kg/ha common vetch + 60 kg/ha oats + 40 kg/ha sunflower;
60 kg/ha common vetch + 120 kg/ha oats + 20 kg/ha sunflower;
10-12 kg/ha sunflower + 100-150 kg/ha pea or faba beans;
18-20 kg/ha sunflower + 100-150 kg/ha pelushka + 40-60 kg/ha oats;
10-12 kg/ha sunflower + 140-160 kg/ha faba beans;
10-12 kg/ha sunflower + 100-150 kg/ha lupine.

Seed sowing depth

The sowing depth of sunflower seeds with sufficient moisture in the upper soil layer and on soils of medium granulometric composition is 6-7 cm; with insufficient moisture — 8-10 cm.

On heavy loamy soils, as well as in a cool and wet spring, the sowing depth is reduced to 5-6 cm; on light sandy loam soils it is increased.

Crop care

After sowing, rolling may be required to ensure better contact of seeds with the soil. Conversely, with excessive compaction of the upper soil layer or formation of a soil crust, loosening with rotary hoes or light harrows may be required.

As a rule, 4-5 days before emergence (or 5-6 days after sunflower sowing), the crops are harrowed to destroy the soil crust and destroy seedlings and sprouts of weeds. With severe infestation, pre-emergence spraying of crops with herbicides is carried out.

After emergence, in the phase of 1-2 (3) pairs of true leaves, a second harrowing across the rows is carried out. To avoid damaging plants, harrowing is performed at low speed closer to noon, when plant turgor is weakened and they become less brittle.

According to data from the VNII of Corn, the effectiveness of harrowing after emergence mainly depends on the phase of weed development. When harrowing is carried out in the phase of white threads and weak weed seedlings, they are destroyed by 90% or more; at later phases of weed development, effectiveness decreases: when 1-2 leaves appear, they are destroyed by 87%; at 3-4 leaves — by 68%.

Further care of sunflower crops consists of inter-row treatments using cultivators of the KRN-4.2 type or implements with wire harrows. The number of inter-row cultivations depends on infestation and herbicide use. For most cultivation regions, 2-3 inter-row cultivations are recommended. The last cultivation can be carried out on precision crops with hilling. The first cultivation is carried out to a depth of 6-8 cm with a treated band width of 50 cm using weeding harrows. The second cultivation is performed to a depth of 8-10 cm, the third — to 6-8 (10) cm. The width of treated bands for the second and third cultivation is 45 cm; for treatment, hilling shares are used to cover weeds in the rows with soil. Inter-row treatments are stopped when plants reach a height of 60-70 cm.

When carrying out inter-row treatments, attention should be paid to the protective zones of plants, which with precision sowing should be up to 40% of the total area. Although these zones protect plants from cutting and covering with soil during treatments, they are at the same time a place for the spread of weeds.

When using industrial cultivation technology with an appropriate soil tillage system and herbicide use, the need for inter-row treatments is often absent.

Sunflower flowers are pollinated by wind and insects. To prevent empty seeds, pollination with bees is additionally used on sunflower crops. For this, by the beginning of the flowering phase, an apiary is brought to the fields at the rate of 1-2 hives per 1 ha. The effect of using bees reaches 0.1-0.15 t/ha of seed yield increase. Sometimes artificial supplementary pollination can be used for the same purposes.

Sunflower cultivation under irrigation

To obtain high sunflower seed yields, despite its drought resistance, large water reserves in the soil are necessary. For example, under the conditions of Krasnodar krai, to obtain 100 kg of seeds, 172-185 t of water are required (according to other data, 140-200 t). In terms of response to irrigation, sunflower occupies one of the first places among field crops.

Long-term studies of VNIIMK and other experimental research institutions have established that growing sunflower under irrigation in regions of insufficient moisture in the Volga region, North Caucasus, and Ukraine allows doubling seed yield to 3.5-4.5 t/ha, and increasing oil collection by 0.5-1.0 t/ha, protein by 0.2-0.3 t/ha. According to data from the Research Institute of Agriculture of the South-East, sunflower yield under irrigation reaches 4.55 t/ha, whereas without irrigation it is 1.82 t/ha.

When growing under irrigation, moisture-charging and vegetative irrigations are carried out.

Moisture-charging irrigation is carried out in autumn after autumn soil tillage. The water consumption rate is (1200) 2000-3000 m³/ha.

In dry years, usually three vegetative irrigations are carried out:

first — at the beginning of rapid plant growth, that is, 2-3 weeks before the beginning of the flowering phase (or at the stage of formation of 2-3 pairs of leaves);
second — at the beginning of the flowering phase (or head formation);
third — 7-10 days after mass flowering (or during mass flowering).

The irrigation norm for vegetative irrigations is 600-800 m³/ha.

The number and water consumption rate for vegetative irrigations depend on weather conditions and are determined by soil moisture. Irrigation is most effective when soil moisture from emergence to flowering is maintained not below 70%, and from flowering to seed ripening — not below 80% of the least moisture capacity of the soil.

Under irrigation and sufficient fertilizer supply, the sunflower plant stand density can reach 55-60 thousand/ha.

A feature of sunflower cultivation under irrigation is deep autumn plowing to a depth of 25-30 cm, increased rates of mineral fertilizer application, use of an integrated plant protection system against diseases, pests, and weeds, and shallow hilling of plants with wet soil.

Plant protection

When growing sunflower, the herbicide treflan is most widely used at a consumption rate of 5-6 L/ha of the preparation. The effectiveness of treflan depends on the speed of its incorporation and mixing with the soil. Treflan is applied during pre-sowing cultivation; a time gap between application and incorporation of the herbicide is not allowed. Combining application and simultaneous incorporation is possible when using units consisting of POU, 2KPS-4, SP-11, 8BZSS-1, and harrows.

In sunflower crops, prometrin can be used to control annual dicotyledonous weeds at a consumption rate on heavy and medium mechanical composition soils of 2.5-3 kg/ha, or on lighter soils — 1.5-2 kg/ha.

The most promising, economically justified, and environmentally safe is considered to be the band method of herbicide application simultaneously with sowing. This method of application allows treating only bands along the rows 30-35 cm wide, while reducing the preparation consumption by half.

Herbicides permitted for use in sunflower crops include:

HARNES, EC — for controlling annual grass and some dicotyledonous weeds; used for pre-emergence soil spraying;
TROPHY 90, EC — for controlling annual grass and some dicotyledonous weeds; used for pre-sowing soil spraying with incorporation when moisture is insufficient or for pre-emergence application;
ZELLEK-SUPER, EC — for controlling annual grass weeds (common barnyardgrass (Echinochloa crus-galli), foxtail species (Setaria spp.)); used during active weed growth (from the 2-6 leaf phase to tillering);
SANGLI, aqueous solution — for controlling annual and perennial dicotyledonous and grass weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
GLYPHOS, aqueous solution — for controlling annual and perennial dicotyledonous and grass weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
KOSMIK, aqueous solution — for controlling annual and perennial dicotyledonous and grass weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
ROUNDUP, aqueous solution — for controlling annual and perennial dicotyledonous and grass weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
TORNADO, aqueous solution — for controlling annual and perennial weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
ROUNDUP MAX, aqueous solution — for controlling annual and perennial dicotyledonous and grass weeds; used for pre-sowing spraying of vegetating weeds 2-5 days before sunflower sowing;
FRONTIER OPTIMA, EC — for controlling annual grass and some dicotyledonous weeds; used for pre-sowing or pre-emergence soil spraying;
PANTERA, EC — for controlling annual grass weeds (common barnyardgrass (Echinochloa crus-galli), field sorghum, foxtails (Setaria spp.)); spraying of crops is carried out in the phase of 2-4 weed leaves and regardless of the sunflower development phase;
BAGIRA, EC — for controlling perennial grass weeds (quackgrass (Elytrigia repens) and others); spraying of crops is carried out when weeds are 10-15 cm high, regardless of the crop development stage;
SELECT, EC — for controlling annual grass weeds (common barnyardgrass (Echinochloa crus-galli), foxtail species (Setaria spp.)); spraying of crops is carried out in the phase of 2-4 leaves of weeds, regardless of the sunflower development phase; for controlling perennial grass weeds (including quackgrass (Elytrigia repens)), spraying of crops is carried out when quackgrass is 10-20 cm high, regardless of the sunflower development stage;
DEVRINOL, wettable powder — for controlling annual dicotyledonous and grass weeds; pre-sowing or pre-emergence soil spraying is carried out;
STOMP, EC — for controlling annual grass and dicotyledonous weeds; pre-emergence soil spraying is carried out;
PROMETRIN, wettable powder — for controlling annual dicotyledonous and grass weeds; pre-sowing, simultaneous with sowing, or pre-emergence soil spraying is carried out;
DUAP GOLD, EC — for controlling annual grass and some dicotyledonous weeds; pre-sowing or pre-emergence soil spraying is carried out;
TREFLAN, EC — for controlling annual grass and dicotyledonous weeds; pre-sowing, simultaneous with sowing, or pre-emergence soil spraying is carried out;
TRIFLUREX, EC — for controlling annual grass and dicotyledonous weeds; pre-sowing, simultaneous with sowing, or pre-emergence soil spraying is carried out;
FURORE SUPER 7.5, emulsion concentrate — for controlling annual grass weeds (wild oat (Avena fatua), foxtail species (Setaria spp.), common barnyardgrass (Echinochloa crus-galli)); spraying of vegetating weeds is carried out regardless of the sunflower development phase;
FUSILADE SUPER, EC — for controlling annual grass weeds; spraying of crops is carried out in the phase of 2-4 leaves of weeds;
FUSILADE FORTE, EC — for controlling annual grass weeds; spraying of crops is carried out in the phase of 2-4 leaves of weeds;
RACER, EC — for controlling annual dicotyledonous and grass weeds; pre-emergence soil spraying is carried out;
VITOX, EC — for controlling annual dicotyledonous and grass weeds; pre-sowing, simultaneous with sowing, or pre-emergence soil spraying is carried out.

For controlling sunflower pests, the following preparations are used:

against meadow moth (spraying during the growing season) — DECIS EC, SPLENDER EC, ATOM EC, DECIS EXTRA, EC;
against bugs and aphids (spraying during the growing season) — CARBAFOS EC, CARBOFOT EC, FUFANON EC, KEMIFOS EC, BUNCHUK, EC.

Harvesting

The ripening phase in sunflower is characterized by drying of most leaves, yellowing of the back side of the heads, wilting and falling of petals, and hardening of the kernel in normally colored achenes. After the heads dry, the achenes easily fall out of them, which causes yield losses and an increase in volunteer plants in subsequent crops.

Harvesting of sunflower begins in the phase of economic ripeness, that is, when the crops contain at least 90% yellow-brown, brown, and dry heads, and seed moisture is 12-14%. However, such seed moisture is noted during harvest very rarely, especially in the northern and eastern cultivation regions. Therefore, immediately after harvest, to prevent an increase in their moisture in the heap, which contains an admixture of crushed and wet heads, the seeds are dried in special dryers. Seed drying, in turn, is associated with additional labor and resource costs.

A delay in harvesting even by 5-6 days leads to significant yield losses.

Of practical interest in this regard is the pre-harvest drying of sunflower plants, that is, standing (desiccation), by treating crops with magnesium chlorate (20 kg/ha) or reglone 2-3 L/ha (reglone super). Desiccation is carried out (35) 40-45 (50) days after full flowering of plants, when seed moisture is 30-35%. At this moment, the crops contain 50-60% yellow, 20-30% yellow-brown, and 10-20% brown heads. The consumption of magnesium chlorate during aerial spraying is 20 kg/ha, or 2-3 kg/ha of reglone and 100 L of working liquid.

After spraying, harvesting begins under favorable weather conditions after 10-15 days. Seed moisture by this time reaches 12-16%. Thanks to desiccation, the productivity of combines can be increased by 1.5-2 times due to a reduction in the harvested mass by almost 2 times and a decrease in seed losses and total labor costs.

Desiccation of sunflower crops allows starting harvesting 8-10 days earlier than usual, while seeds are obtained with low moisture. Desiccation does not affect seed quality and does not change their fatty acid composition. Magnesium chlorate is not contained in sunflower oil, but it is found in heads in a fairly high amount, therefore they are not suitable for fodder purposes.

Desiccation is especially important for the forest-steppe zone.

Sunflower harvesting is carried out by direct combining with grain combines, for example, SK-5 “Niva”, which are additionally equipped with special attachments PSP-1.5, PSP-1.5M, or 34-103A, as well as trailers 2PTS-5-887A and universal PUN-5 for chopping and spreading stems. “Don” combines for the same purposes are equipped with attachments PSP-8 or PSP-10. A combine equipped with PSP-1.5 cuts the heads, threshes the seeds, and collects the seeds in the bunker. Stems are cut at a height of 10-20 cm, chopped into parts up to 15 cm long, and spread across the field; threshed heads are also chopped, collected in transport vehicles, or spread across the field.

Threshed seeds are cleaned using a heap cleaner OVP-20, then passed through a grain cleaning machine OS-4.5A or units ZAV-20 and ZAV-40.

The organization of flow harvesting of sunflower plays an important role. It is necessary to ensure coordination of the entire complex of technological operations, which must be performed by specialized units at all stages of the technological process: preparation of fields for harvesting, threshing and transportation of seeds from the field to the threshing floor, cleaning and drying of seeds, removal of seeds to receiving points, collection and preparation of threshed heads for feed, fertilizer application, and soil preparation.

Seeds of high-oil varieties must be stored at moisture not more than (6) 7 (8)% in a layer up to 1 m. In bags, sunflower seeds are allowed to be stored at moisture 8-10%. The moisture of seeds in storage intended for technical purposes must be not more than 10-12%. Undried seeds quickly become rancid and lose their germination.

The stems remaining in the fields can be chopped using heavy disk harrows or plows with subsequent plowing in.

The optimal dates for harvesting sunflower for silage are the beginning of flowering, before the stems become coarse. In this case, harvesting begins at the beginning of flowering and ends by the full flowering phase. Harvesting of mixed crops of sunflower with other crops for silage also begins at the beginning or at the full flowering phase. When using sunflower to obtain green mass in fresh form, harvesting begins in the flowering phase of legumes, ending by the time of pod formation. If harvesting is delayed, that is, if sunflower is cut after flowering, the quality of silage sharply decreases, since the stems become very coarse and the protein content greatly decreases.

Since sunflower is a valuable honey plant, cutting is carried out in the flowering phase early in the morning and late in the evening, when bees are resting.

For harvesting sunflower in pure form or in mixture with other crops, any silage harvesters can be used.

Resource-saving intensive technology

The resource-saving intensive technology of sunflower cultivation is designed to obtain 2-2.5 t/ha of seeds and reduce the number of operations from 12-13 under ordinary technology to 7-9, as well as to reduce direct labor costs by 20% and reduce production cost by 7-8%.

The technology provides for:

scientifically based placement of sunflower in crop rotation;
use of different-maturity, highly productive, zoned, disease-resistant varieties and hybrids suitable for mechanized cultivation;
providing plants with nutrients based on the planned yield;
use of seeds of high reproductions and sowing conditions;
precise, dosed application of mineral fertilizers;
a systemic complex of technological operations aimed at efficient use of fuel, energy, and other resources;
performance of agricultural practices at optimal times.

The technology provides for the use of moisture-saving, soil-protective methods in the system of primary and pre-sowing soil treatments while reducing the number of all operations through the application of highly effective herbicides, the use of an integrated plant protection system against pests, diseases, and weeds, and the formation of a specified (taking into account moisture supply) plant stand density.

Necessary conditions for using the technology are:

flow of work during harvesting and post-harvest seed processing;
use of high-performance and advanced machinery;
performance of all work within specified deadlines;
observance of agrotechnics;
use of progressive forms of organization and remuneration of labor.

In experiments conducted by the Department of Agriculture and Plant Growing of GUS under the leadership of Professor V. S. Niklyaev together with specialists of AOZT “Progress” of Valuysky district, Belgorod oblast, in 1995-1997, sunflower yield using resource-saving technology on an area of 150-200 ha averaged over three years was 2.2 t/ha (maximum in 1995 reached 2.4 t/ha), whereas with ordinary technology — 1.5 t/ha.

In 1995 and 1996, the variety Belgorodsky 5 was experimentally grown using this technology, and in 1997 — the hybrid Veidelevsky 80. They were placed after winter wheat following clean fallow. Particular attention was paid to soil treatment. After wheat harvest, thorough disk disking was carried out to a depth of 8-10 cm, followed by quality plowing to a depth of 25-27 cm. In spring, harrowing of autumn plowing was carried out when the soil was in a state of physical ripeness, and then pre-sowing cultivation to a depth of 6-8 cm. Carrying out these practices contributed to good accumulation of moisture and nutrients, improvement of the soil air regime, activation of soil biological activity, reduction of field infestation, and reduction in the number of pests and plant disease agents.

Before sowing, the field had a well-leveled surface, a firm seedbed; the number of soil clods 1-5 cm in size in the treated layer was not less than 80% by mass. Clods larger than 10 cm were not noted.

Before pre-sowing cultivation, 150 kg was applied, and simultaneously with sowing, 80-100 kg of nitrophoska per 1 ha. Organic fertilizers were applied to the preceding crop.

The seed material was treated; seeds of the first reproduction and class 1 were used. Sowing began when the soil steadily warmed at the depth of seed placement to 10-12 °C. Sowing was carried out in a short time by the flow method; the sowing method was precision, row spacing 70 cm, seed placement depth 6-7 cm into the moist surface soil layer. The seeding rate was 60-70 thousand germinating achenes per 1 ha (varied within these limits depending on the variety (hybrid) and moisture supply in the sowing year). The seeding rates were calculated to obtain by the time of harvest a plant stand density of 45-50 thousand plants per 1 ha.

Main crop care operations: post-emergence harrowing at the stage of formation of 2-3 pairs of true leaves in sunflower and 2-3 inter-row treatments depending on infestation and the nature of crop infestation, as well as soil compaction. The first inter-row treatment was carried out to a depth of 6-8 cm, the second — to a depth of 8-10 cm, the third included simultaneous covering of weeds in the rows using hilling attachments.

Desiccation of crops was used. Harvesting was carried out by grain combines with appropriate attachments using the group method. At the same time, post-harvest processing of achenes was carried out.

The economic assessment of the technology showed a reduction in labor costs for producing 100 kg of achenes by 12-15% and a reduction in total energy costs by 8-10%.

Sunflower varieties

Classification

Sunflower varieties and hybrids, depending on the size of achenes, their oil content, and hull content, are divided into three groups:

oilseed;
confectionery;
intermediate.

Oilseed varieties and hybrids are distinguished by a thin stem, height 1.5-2.5 m, head 15-20 cm in diameter, small achenes (7) 8-13 (14) mm long and 1000-seed weight from 35 to 75 (85) g, low hull content (22) 25-30 (36)%, large kernel densely filling the cavity, containing (38) 53-56 (63)% oil, which is 40-56% of the achene mass. They are of greatest production importance for obtaining vegetable oil. They are also more resistant to sunflower moth and broomrape (Orobanche sp.).

Confectionery varieties and hybrids are distinguished by a thick stem up to 4 m high, head 25-40 cm in diameter, large achenes (11) 15-23 (25) mm long, 1000-seed weight from 100 to 170 g, with a thick ribbed pericarp, high hull content 42-56%, kernel loosely filling the cavity (half), oil content 20-35%. Plants of these varieties and hybrids are usually large and tall, therefore their main purpose is silage and green mass production, sometimes for seed production. They are sown on small areas.

Varieties and hybrids of intermediate type occupy an intermediate position in morphological characteristics. In achene fullness, intermediate forms are closer to oilseed varieties and hybrids; in other characteristics — to confectionery.

Armored breeding varieties and hybrids of sunflower are varieties and hybrids in the hull of whose achenes there is a black layer of phytomelanin, protecting the fruits from sunflower moth and some other pests.

Depending on the length of the growing season, sunflower varieties and hybrids are divided into:

mid-season (120-140 days, Vavilov, 1986; according to other data 100-110 days, Kolomeichenko, 2007);
early (100-120 days, Vavilov, 1986; according to other data 90-100 days (mid-early), Kolomeichenko, 2007);
very early (80-100 days, Vavilov, 1986; according to other data 80-90 days (early), Kolomeichenko, 2007).

The length of the growing season varies significantly depending on soil, climatic, and weather conditions, but differences between varieties and hybrids of different groups are preserved.

Mid-season hybrids and varieties are characterized by the highest yield: at variety-testing plots sunflower can produce up to 3-4 t/ha, on farms — 2.5-3.5 t/ha; their oil content is 50-54%, hull content — 19-22%, armoredness — 98-100%, 1000-achene weight from 65 to 85 g, color black-gray, striped. Oil collection of these varieties and hybrids reaches 1.5-2 t/ha.

Mid-early sunflower hybrids and varieties ripen 5-9 days earlier than mid-season ones. Their yield is 2-3 t/ha, oil content — 48-52%.

Early sunflower hybrids and varieties produce a harvest 8-12 days earlier than mid-season ones. They are usually cultivated in the northern and eastern regions of Russia (Western Siberia, Volga region, Central Chernozem Zone). Yield is 1.5-2.5 t/ha, oil content — 41-53%.

To obtain high and stable yields over years on farms specializing in sunflower cultivation, it is advisable to sow 2-3 hybrids or varieties with different ripening periods.

Mid-season

Mid-season varieties are distinguished by high productivity. Plant height of these varieties reaches 145-200 cm, seeds black-gray, striped and non-striped. All are resistant to sunflower moth and broomrape A and B.

Peredovik improved. Developed by VNIIMK. Widely zoned.

Armavirsky 3497 improved. Developed by the Armavir Experimental Station of VNIIMK. Zoned in Ukraine and the North Caucasus.

VNIIMK 1646 improved. Developed by the Armavir Experimental Station of VNIIMK. Zoned in the North Caucasus.

VNIIMK 6540 improved. Developed by VNIIMK. Zoned in Ukraine, the North Caucasus, Kazakhstan, and Georgia.

VNIIMK 8931 improved. Developed by VNIIMK. Zoned in Krasnodar krai and Kalmykia (Russia), Alma-Ata oblast (Kazakhstan).

Zelenka 368 improved. Created at the Veidelevka Experimental Field. Zoned in Ukraine.

Mayak. Created by the Don Experimental Station. Zoned in the North Caucasus and Crimea.

Smena improved. Developed by VNIIMK. Zoned in the North Caucasus.

Mid-season varieties also include VNIIMK 6540 improved, Odessky 63, Pervenets, Progress.

Early

Early varieties usually are inferior in yield and oil content to mid-season varieties. Plant height is lower. Under the conditions of Krasnodar krai, ripening occurs 6-10 days earlier than mid-season varieties.

VNIIMK 8883 improved. Developed by VNIIMK. Zoned in the Volga region and Kemerovo oblast.

Voskhod. Created at the Veidelevka Experimental Field. Zoned for Belgorod (Russia), Poltava (Ukraine), East Kazakhstan, and Semipalatinsk (Kazakhstan) oblasts.

Zarya. Created at the Veidelevka Experimental Field. Zoned in Kurgan (Russia) and Pavlodar (Kazakhstan) oblasts.

Early varieties also include Voronezhsky 272, Zenit, hybrid Pochin.

Very early

Very early varieties are inferior in productivity and oil content to early and mid-season varieties, but under the conditions of Krasnodar krai they ripen 10-12 days earlier than mid-season varieties and 7-10 days earlier than early varieties.

Armavirets. Developed by the Armavir Experimental Station. Zoned for Kuibyshev and Orenburg (Russia), East Kazakhstan (Kazakhstan) oblasts.

Yenisei (503). Developed by Krasnoyarsk NIISKh. Zoned for Siberia and the autonomous republics of the Volga region.

Salyut. Developed by VNIIMK. Widely zoned.

Yugovostochny. Developed by the Research Institute of Agriculture of the South-East. Zoned for Novosibirsk and Orenburg oblasts.

Very early varieties also include: Nadezhny, Trudovik.

Silage

In agricultural production, oilseed hybrids or sunflower varieties that produce low green fodder yields are often used for fodder purposes. However, special silage varieties are more suitable for fodder purposes; they are distinguished by greater branching and leafiness, form many heads, and their green mass is more tender. The green mass of such varieties and hybrids contains 12.4% protein, 26.2% fiber, and 11.5% ash. For comparison, early sunflower varieties contain 7.0% protein, 32.4% fiber, and 8.6% ash.

Silage sunflower varieties include: VNIIMK 6540 improved, Mayak, Belozerny giant, Giant 549, Stepnoy silage.

References

Vavilov P. P., Gritsenko V. V., Kuznetsov V. S. et al. (1986). Plant Growing. Ed. Vavilov P. P. 5th ed., revised and expanded. Moscow: Agropromizdat.
Kolomeichenko V. V. (2007). Plant Growing/Textbook. Moscow: Agrobusinesscenter.
Niklyaev V. S. (2000). Fundamentals of Agricultural Production Technology. Agriculture and Plant Growing. Moscow: “Bylina”.