Foliar fertiliser recommendation for sunflowers
Sunflowers require a warm, dry climate with an average temperature of at least 15.5 degrees Celsius between May and September. They thrive best in a typical maize growing regions (Hungary, Bulgaria, Ukraine).
Herbicide application
Sunflowers are sensitive to competition from weeds/grasses up to the 6-leaf stage. Therefore, a good weed control at this stage is a prerequisite for high yields.
One component to achieve this goal is Herbosol® - an additive to improve the effect of soil herbicides. The addition of Herbosol® improves the effectiveness of the herbicide treatment by reducing the amount of fine droplets and thus achieving a better distribution of the herbicide on the target area. It binds the active ingredient more tightly to the soil particles and thus prevents the active ingredient from leaching into deeper layers.
To increase the tolerance of foliar post-emergence herbicide spray, use 2 – 3 l/ha Aminosol®.
Fertilisation of sunflowers
Sunflowers develop a far-reaching root system and therefore have a high nutrient-uptake capacity. In order to meet the supply of the main nutrients, it is important to know their status in the soil. Based on a soil analysis, targeted dressing with nitrogen, phosphorus, potassium, sulphur or magnesium or lime can then be carried out in accordance with the legal requirements.
Caution is advised when applying N fertiliser, as excess of N leads to delayed ripening and increased disease pressure. As the availability of potassium and phosphorus in the soil may be limited due to e.g. cold and wet weather in spring, we recommend the use of Lebosol®-PK-Max from the 4-leaf stage for a better start of the crop.
A sufficient supply of magnesium is necessary to ensure a yield-effective development of chlorophyll. Sunflowers have a medium sulphur requirement. For high, stable yields, a sufficient sulphur supply must be ensured. Here Lebosol®-MagSOFT SC or Lebosol®-Sulphur 800 SC can play an important role in supplementing the basic fertilisation of magnesium and/or sulphur.
Micronutrients
The influence of trace elements on yield and especially on quality is quite high when growing sunflowers.
Sunflowers have a high boron requirement. Therefore, especially on alkaline, light and sandy soils as well as in regions with early summer drought, attention should be paid to the boron supply. Boron deficiency is first visible on the leaves, whose edges show honeycomb-like blisters. On the stem, cracks run diagonally and subsequently break. In case of pronounced deficiency, the growing point dies before flowering. The flower heads themselves are malformed with undeveloped seeds. Ideal application is 1 – 2 times Lebosol®-AqueBoron SC – from the 4-leaf stage.
With regard to copper supply, sunflowers are very demanding. As a result of copper deficiency in sunflowers, strongly inhibited growth, wilting symptoms on the young leaves as well as suppressed flower formation or misshapen flowers can be observed. Approximately 100 – 150 g of copper/ha are required for a high yield.
Manganese is involved in the control of photosynthesis. This improves the assimilation performance of the sunflower and has a lasting positive influence on the yield. Through its regulating effect in the fatty acid metabolism, manganese ensures a high oil content. The manganese requirement of sunflowers is between 400 – 600 g/ha depending on the yield.
VITALoSol® GOLD SC combines the micronutrients copper, manganese and sulphur and thus covers the nutrient requirements of sunflowers very well at an application rate of 1.5 – 3 l/ha.
At a higher concentration of VITALoSol® GOLD SC, the oversupply of these elements strengthens the stress tolerance and defence mechanisms of plants. Use VITALoSol® GOLD SC in the spray sequence to ensure the success of the crop protection.
In order to plan the targeted use of foliar fertilisation, leaf analysis has proven to be a useful tool for detecting hidden hunger. This is extremely important because even an invisible lack of nutrients leads to a loss of yield and quality.