Sunflower requires a total temperature around 2600 – 2850 °C during the growing period (100 – 150 days). Due to its deep and taproot system, its production performance in soils with problems such as drought, salinity and old age is better than other crops. Although it grows in all kinds of soils, it likes soils with good drainage, neutral PH (6.5 – 7.5) and high water retention capacity more. It likes acidic soils with high ground water and has an average tolerance to salinity. The minimum soil temperature for sunflower germination should be 8-10 °C.
Ecological Requirements of Sunflower Temperature requirements: Sunflower is a relatively drought-resistant plant due to its strong and deep root system. As an annual and summer plant, it is grown in subtropical and temperate climatic zones (where the average temperature in July does not fall below 18-19 oC). The total temperature requirement during the vegetation period (80-130 days) is 2600-2850oC. During the germination period, 4-5 oC is required as a minimum, 8-10oC as a minimum and 12-14oC as an optimum for a proper emergence. Temperatures above 30oC during the development period inhibit growth, and above 40oC pollen is generally unable to germinate and fertilization is either weak or absent. It is not very sensitive to late spring frosts. Young plants are resistant to frost. Seedlings can survive in the cotyledon stage at -5oC. It grows better in sunny, warm places with an average monthly temperature of 25oC during the growing period.
Water and soil demand: Sunflower can use 3 m deep water with its developed root system. Sunflower plant consumes 200 kg of water on average during the development period. Although it is highly tolerant to drought, if the drought persists for a long time, the tables remain small, the seed set is low and the yield decreases significantly. As a light and sun-loving species, sunflower needs sufficient light and does not like shade. Sunflower is a plant that can grow in a wide range from heavy clay soils to light sandy soils, from slightly acidic soils to alkaline soils, except very heavy and sandy soils. It can grow best in soils rich in organic matter, humus, alluvial, deep profile and good water retention capacity. The ideal soil pH for its development is 6-7. Sunflower is more salt tolerant than sorghum, soybean, paddy, maize, maize, broad bean, flax and bean and can grow in soils with total soluble salts between 0.640-0.384%.
Sunflower Soil Preparation
Main crop soil preparation: Soil preparation is started in the fall following the pre-crop harvest. The field is plowed with a plow at a depth of 20-25 cm. However, instead of deep plowing in this way every year, plowing at varying depths will reduce the cost and more importantly, it will prevent the formation of a hard soil layer called plow bottom. As the soil surface enters the winter plowed, water uptake increases and the physical properties of the soil improve with freezing and thawing. If there is grazing in the field due to autumn rains following the first plowing, the soil is cultivated with a crowbar at a depth of 10-15 cm before entering the winter to ensure that the weeds are buried deeply. In the spring, deep tillage should be avoided, and when the soil reaches the right level, it is plowed superficially with a plow in order to prevent the soil from escaping. In general, if the soil is not weeded and hard, it can be cultivated with a cultivator, and if it is rough, it can be cultivated superficially with a disc harrow at a depth of 10-15 cm. The soil can also be cultivated superficially with rototiller type combined tools. In this way, it will be possible to work the soil from the bottom, break it up and level it at a certain level.
Second crop soil preparation: Stubble should not be burned after canola (rapeseed), barley and wheat harvest. In the field where the crop stalks are cut from the bottom and the stalk-straw and weeds are removed with a rake, the soil is watered sufficiently by making compartments (pans) for irrigation. Depending on the air temperature, the soil that reaches the pan within 4-5 days is plowed at a depth of 1820 cm and disked. If the sowing will not be done with combined seeder, the fertilizers to be given in the sowing are scattered on the soil with a centrifugal fertilizer machine, if spraying is required for weeds or soil pests, it is applied, fertilizer and medicine are mixed into the soil at the sowing depth with a disc harrow or harrow. Then, the soil is pressed by pulling the slide and made ready for planting. The harrow is also useful in terms of leveling the soil to a certain extent.
How to Fertilize Sunflower?
Fertilization: In addition to agronomic operations, the desired, optimum level of yield can be achieved with an economical fertilization. In order for fertilization to be reflected on the yield at the desired level and optimum, soil analysis should be done beforehand and there should be sufficient moisture in the soil. Again, application of fertilization and irrigation together significantly increases sunflower yield. In order to improve the organic structure of the soil and for high yields, if possible, the application of farm manure also gives good results. For this reason, it is appropriate to apply 3-4 tons of farm manure per decare in autumn. In sunflower, under dry conditions, 7-8 kg/da N, P, K as pure matter; under irrigated conditions, these amounts are applied approximately 10 kg/da. Fertilizers can be applied as a mixture or as a compound fertilizer (20-20-0 or 15-15-15).
Half of the nitrogen fertilizer can be applied as ammonium sulfate (21% N) or triple super phosphate mixture as ammonium nitrate (26% N) depending on the condition of the soil in the mixture, and the remaining half of the nitrogen fertilizer is applied before the throat filling process and mixed into the soil with a rake or disc harrow, and the other half is applied as ammonium nitrate or urea during hoeing, throat filling process and before irrigation. All nitrogen fertilizer can also be applied as compound fertilizer before planting. If a combined planting machine is used in sowing, the fertilizers are applied at a depth of 10-12 cm in the soil and in bands.
When to Plant Sunflower?
Sowing: Sunflower sowing can be done in a very wide time period. However, the main (first) crop sowing time is determined by air temperature and soil temper. Accordingly, main and second crop sunflower can be sown from mid-March to mid-July. Sowing is done in March and April in the Aegean, Southern and Southeastern Regions; in April in the Marmara, Central Anatolia and Black Sea Regions; and in May in the Eastern Anatolia Region. For a good sowing, the seed bed should have sufficient moisture, should be well cultivated; it should not be too fluffy and loose; stubble residues and weeds should be cleaned. In this case, the most suitable sowing depth is 3-4 cm. When necessary in terms of soil tempering, sowing can be done even at a depth of 7-8 cm. However, when sowing deeper than necessary, the emergence from the soil will not be on time and will be wavy and distorted. Although it is known that sunflower sowing is done by sprinkling, plow lines, and hearth method; sowing with a sowing machine in a well-prepared field is the most appropriate one. Today, 750-1500 g/da of seed is used per decare with cotton seeder widely used in our country, and 250-350 g/da of seed is used with a well-adjusted precision (pneumatic or mechanical) sowing machine, depending on the 1000 grain weight of the seed. Sowing with a precision sowing machine is also important in terms of eliminating the labor cost of misplowing.
How to Care for Sunflower?
Care Procedures: Depending on the air and soil temperature and the characteristics of the variety, sunflower emerges in 5-10, on average 7 days after sowing, reaches 10-15 cm height after 15-20 days (singling time), reaches 30-35 cm height after 25-35 days (throat filling time), blooms after 60-75 days, reaches physiological maturity after approximately 85-120 days and is harvested after 90-130 days. Weed control: In addition to pesticide control, mechanical control is also required in weed control. Medicated weed control: In addition to pre-sowing tillage and spraying with drugs such as trifluralin or EPTC, some preparations can be used in the 3-4 leaf stage before and after emergence following sowing.
These drugs should be used in accordance with their description. Mechanical weed control after sowing – before and after emergence: As it is known, weed seeds germinate quickly and can cover the field. When such a problem is encountered, most of the germinated weeds are destroyed by harrowing the field very superficially in the pre-emergence period. However, this type of application requires a very skillful application.
Weeds in the field at the 2-4 leaf stage, if not controlled, can grow rapidly and suppress sunflower seedlings. Depending on the situation, 7-10% of sunflower seedlings will be lost from the field with superficial harrowing between the rows or perpendicular to the rows if necessary.
Hoeing in sunflower: Sunflower is a hoeing plant. Timely hoeing is important in terms of controlling weeds, preserving moisture by fluffing the soil surface and high yield. Hoeing is done with a hand hoe in small enterprises. Sunflower should be planted in the row for machine intermediate tillage-hoeing. There are generally two hoes in sunflower. The first one should be done during kicking and the second one should be done when the plants reach 30-35 cm in height. During hoeing, the soil cream layer is broken between the rows with a crowbar pulled by a tractor, the soil is fluffed up and weeds are combated. However, the weeds on the rows should be removed with a hand hoe. If necessary, after emergence, if there is a weed problem, the milling cutter should be passed immediately. If weed control is done well until the sunflower reaches a height of 25-35 cm and no damage is seen, there is no weed growth under it as it grows rapidly after this period and covers the soil surface, and this situation is also important in terms of maintaining the soil temper.
How often to irrigate sunflower?
Irrigation Sunflower can grow in dry conditions. It can be produced without irrigation in areas with an annual rainfall of 500-600 mm and especially in areas where nearly half of this rainfall falls during the sunflower development period. However, when adequate irrigation is applied at appropriate times, yield increase can reach 100%, especially in hybrid varieties. Sunflower uses 20% of the water it needs from the time it emerges from the soil until the stage of table formation. Table formation-flowering period is the most critical period and the plant uses 60% of the water it needs in this period and the remaining 20% in the oil formation period after flowering. Three irrigations to be made in these periods are important in terms of high yield. In particular, irrigation to be carried out during the flowering period in order to prevent the damage caused by high temperatures during the flowering period is of great importance. It is recommended to irrigate by furrow, drip or sprinkling. However, sprinkler irrigation should not be used where diseases are common and during flowering.
Do Birds Damage Sunflowers?
Bird Pests: As in many countries, sparrows (Passer spp.), crows (Corvus spp.) and starlings (Sturnus spp.) are the main bird pests in our country. Generally, the damage caused by birds is proportionally less in intensive production areas, but more damage is encountered in small production areas. The difference in the damage caused by bird damage between varieties is related to preference, as well as many factors such as grain condition, grain shape, grain flavor, compounds contained in the grains and grain shell thickness. Some cultural measures can be effective against bird damage. Bird damage is more common in areas close to places such as woods and swamps. However, it is important not to be late in harvesting in order to prevent increased bird damage. In addition to mechanical measures such as making noise mechanically, using topatars that explode at certain intervals, etc., stretching raffia strips that make noise with the wind at the edge of the field and hanging brightly colored signs can be counted among the measures. For an effective control, if any disease or pest is seen, the nearest control organization should be contacted, the instructions for use of the pesticide should be examined well and timely control should be carried out.