Sunflower production

• Sunflower


  A crop which performs well under drought conditions

  
• Sunflower


  • Sensitive to high soil temperatures during emergence
  • Particularly sensitive to bird damage

  
• Sunflower has advantages of drought tolerance and low input cost

  
• Sunflower has a short growth season which allows it to be planted over a period of at least three months

  
• Sunflower only belongs in a crop rotation system

  
• Soil for sunflower


  • Clay percentage between 15-55%
  • Prefer soils with less than 20% clay
• Sunflower plant


  • Has a deep and finely branched tap-root system
  • Can utilize water from deep soil layers, even deeper than 2m
• Shallow soils such as Westleigh, Estcourt, Kroonstad and other duplex soils are suitable for sunflower cultivation
• Soils to avoid for sunflower


  • Light-textured soils susceptible to wind erosion
  • Waterlogged soils
  • Soils with pH lower than 4.6 (KCl) due to high aluminium levels
• Yield potential


  Essential to make a reliable assessment for effective planning
• Yield and yield reliability are the most important criteria when evaluating sunflower cultivars

  
• Yield reliability


  The minimum yield which will be achieved by a cultivar in nine out of ten cases
• Soil cultivation for sunflower


  • Aim to utilise rainfall and soil moisture to maximum
  • Apply practices to decrease runoff losses
  • Primary cultivations like ploughing or chiselling to break up limiting layers, destroy weeds, provide suitable seedbed and break soil surface

  
• Sunflower benefits from dense mulches of previous crops like maize or sorghum

  
• Soil compaction can be a serious problem, especially in sandy soils, limiting root development and water utilisation
• Planting date for sunflower


  • Eastern areas: Nov to Dec

  Western areas: Nov to mid-Jan

  Factors to consider: frost, soil temp, moisture, rainfall, other crops, bird damage

  
• High soil temperatures during planting in warm western areas with sandy soils can lead to poor emergence
• Row width for sunflower

  90-100cm mostly used, but wider rows can also be used to fit farm implements

  Wide row spacing only suitable for yield potentials lower than 1500 kg/ha

  
• Plant density for sunflower


  Correct and uniform plant density is key

  1000-1200 kg/ha: 25,000-30,000 plants/ha

  1200-2000 kg/ha: 30,000-35,000 plants/ha

  Avoid densities higher than 30,000 plants/ha at yield potentials below 1200 kg/ha

  
• Sunflower head


  • 30 cm produced only 19 g of seed (20 % seed setting)
  • 16 cm head produced 54 g of seed (80 % seed setting)

  
• High plant densities


  • Cause higher occurrence of lodging, which should be avoided
  • Plant densities higher than 30 000 plants/ha should be avoided at yield potentials below 1200 kg/ha as the high rate of water use often causes water stress, leading to poor yield or even crop failure
• It is essential that sunflower be spaced evenly

  
• The accuracy of the planter determines whether an even plant density will be achieved
• Guidelines for plant density at different yield potential levels


  • 1000 - 1200 kg/ha: 25 000 - 30 000 plants/ha
  • 1200 - 2000 kg/ha: 30 000 - 35 000 plants/ha
• Sunflower seed requirements (kg/ha) according to plant density and seed size


  • 25 000 plants/ha: 4 g - 1.42 kg/ha, 3 g - 1.81 kg/ha, 2 g - 2.32 kg/ha
  • 30 000 plants/ha: 4 g - 1.71 kg/ha, 3 g - 2.17 kg/ha, 2 g - 2.78 kg/ha
  • 35 000 plants/ha: 4 g - 1.99 kg/ha, 3 g - 2.54 kg/ha, 2 g - 3.24 kg/ha

  
• Planting depth


  • In soil with high clay content, seeds are planted at 25 mm depth
  • In sandy soils, seeds can be planted at up to 50 mm depth
• Planting process


  • Planter should be able to space seeds evenly, have good depth control mechanism, and be equipped with press wheels
  • Good contact between seed and soil is essential, press wheels should only exercise light pressure to avoid compaction
• Avoid extremely high temperatures during planting time, as well as the possibility of frost damage
• The quantity of water preserved in the soil before planting time has a major influence on the establishment, growth and survival of the plants during droughts
• Use more than one planting date to spread the risk of drought
• In clay soils, sunflowers should be planted in narrow rows (90 to 100 cm) to improve soil water utilisation

  
• Planters with press wheels that compact the soil alongside the seed are more suitable than those with press wheels exercising direct pressure from above
• Sunflower utilises soil nutrients exceptionally well


  • Finely branched and extensive root system allows contact with nutrients that cannot be utilised by other crops

  
• Sunflower normally reacts well to nitrogen and phosphorus fertilisation where there is a shortage of these elements in the soil

  
• Soil analyses will not only lead to more appropriate fertilisation levels, but can also significantly limit unnecessary fertilisation costs