• 16°
    Austria
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  • Soil texture
    Medium heavy soils, no waterlogging
  • Min. temperature
    8°C soil temperature
  • pH
    Tolerant of slightly acidic to slightly alkaline soils; pH optimal: 7.0
  • Water demand
    min. 250l/m²
  • Vernalisation
    -
  • Plant density
    Depending on date and variety 6-7 grains/m²
  • Seeding Depth
    2-3 cm
Sunflower
Sunflowers prefer medium clay soils with adequate nutrient replenishment and water storage capacity. They also cope well with loamy sandy soils and lighter loess and gravel soils, if rainfall and distribution are appropriate. Its tap root can penetrate several meters into the soil and exploit nutrients and water reserves there. However, after sunflowers have been grown, these reserves are often depleted. Sunflowers need a relatively warm and dry climate without fog to ripen well in autumn. With early-maturing varieties, the growing areas have been expanded. An important factor is having as little fog as possible in autumn. In areas where grain maize matures around FAO 250-270, sunflowers can also be cultivated successfully.
Key facts
  • Nitrogen fertilization is done in one dose.
  • Ensure sufficient phosphorus supply.
  • Sunflower needs approximately 30kg sulphur/ha (75kg SO3/ha)
  • Sunflower is sensitive to chloride.
  • Ensure an adequate boron supply in the seeding stage.
General Information
General Information
Nutrient Demand
Nutrient Demand
Fertilization
Fertilization
Sunflowers are grown as striated varieties which are used unpeeled for birdseed and hulled for human consumption and black seeded varieties for oil extraction. They are planted using single grain sowing with 70cm row spacing. Sowing six to seven grains/m² makes for ideal plant spacing. Meanwhile, hybrids are used almost exclusively. The main focus is on emergence, mating and harvest. In between, they are easy and undemanding. Except for seed dressing and herbicides, little plant protection is used. Slug pellets are usually applied to protect young seedlings. Hares feeding on crops during delayed juvenile development and birds feeding on almost mature flower heads are notable problems.
Sunflowers need nutrients
Sunflowers, like all oil crops, need a good phosphorus fertilization in addition to the nitrogen supply. Also, potassium and sulphur must not be overlooked. Phosphorus is not only important for growth; it is incorporated into the grains and plays an important role in energy metabolism and oil production. Sunflowers need potassium for water supply and the assimilation into the grain. Most potassium remains in the straw and thus for the subsequent crop in the field. If potassium is only fertilized at the extraction level and previously fertilized in autumn, fertilizer containing chloride may be used. For fertilization amounts above the extraction level, and with doses in the spring, sulphuric acid potassium fertilizers are definitely preferred, since high chloride contents negatively influence the subsequent oil content of the grain. Fertilization with NPK formulas based on potassium sulphate simultaneously ensures the sulphur requirement of 30-40kg S/ha (75-100kg SO3). Sunflowers need sufficient boron by the juvenile development stage. In addition to boron-containing complex fertilizers, boron-containing foliar fertilizers may also be used.
Extraction rates of sunflowers

Element

Uptake

(Unit/t of production)

Removal

(Unit/t of production)

Sensitivity to deficiency

N

45

24

Very Sensitive

P2O5

16

12

Sensitive

K2O

16

10.5

Very Sensitive

TE

Boron: Soil fertilization 1.2kg/ha boron: Foliar fertilization 300-500g/ha

The table shows the uptake and extraction per tonne of sunflower grain yield. Sunflowers need mainly nitrogen, phosphorus and potassium. However, sulphur, magnesium and boron must also be present in appropriate amounts. For example, sunflower grain yield of 3to/ha absorbs up to 135kg N/ha. If 70kg N/ha is provided from the soil, then another 65kg N/ha would be fertilized. 72kg N/ha would be removed from the field by the harvest.
FERTILIZING SUNFLOWERS

Sunflowers need to concentrate nutrients until bud formation. Afterwards, most of the nutrients are translocated within the plant or used for water absorption (potassium). All of the required nitrogen is usually applied before cultivation. The large need for nutrients is in the first phase of growth. Therefore, splitting doses is not needed. Sulphur-containing NPK fertilizers provide the required phosphorus potassium and sulphur directly at cultivation or in autumn or early spring. Liming as soil preparation should also be done in autumn or early spring. A maximum of 1.500kg CaO/ha - best as carbonate of lime, should be used to avoid boron fixation,

The yield parameters of sunflower:

  • Number of plants/m²
  • Number of grains in the flower head
  • Thousand grain's weight


Growing six to seven plants per m² and a strong and healthy stalk and leaf mass makes for ideal conditions and a high yield. For this, a nitrogen supply of 50-65kg N/ha is usually sufficient, also for stock storage and to prevent susceptibility to fungal diseases. The lush root system can have extreme nutrient uptake, especially in humus rich soils.


One application in spring

One application in spring

Single dose of total nutrient requirements:
Sunflowers need the nutrients concentrated at the beginning of growth. Therefore, fertilization before sowing is ideal. All required nutrients can be given in one dose. Nitrogen is fertilized modestly in comparison to the extraction rate, to avoid the effects described above. Nitrogen fertilizers with sulphur, nitrogen phosphorus or NPK fertilizers or low-chloride potash fertilizers are particularly suitable. Since this is an oil plant, particular attention must be given to the supply of boron.