Modern agricultural production has reached a level where basic nitrogen, phosphorus and potassium (NPK) application is no longer sufficient to achieve maximum profitability. When it comes to Ukraine's strategic crops — sunflower and corn — micronutrients are increasingly becoming a limiting factor.
Zinc (Zn) and boron (B) are not just additives, but activators for biochemical processes. In this article, we will examine why a deficiency of even a few grams of these elements can cost a farmer up to 20-30% of their yield.
Boron — the foundation of sunflower yield
Sunflowers are the main ‘consumers’ of boron among field crops. Unlike many elements, boron practically does not move within the plant (reutilisation is almost zero). This means that it must be supplied steadily throughout the entire growing season.
Why boron is critically important:
- Pollen fertility: Without sufficient boron, pollen becomes sterile, leading to empty seeds (empty flowers) in the centre of the basket.
- Tissue elasticity: Boron is responsible for the integrity of cell walls. Its deficiency causes the stem to crack, making it easy for diseases (phomopsis, sclerotinia) to penetrate.
- Root system development: The element stimulates the growth of growth points, ensuring better absorption of moisture from deep soil layers.
Agronomist’s advice: The optimal window for foliar feeding of sunflowers with boron is the 4–8 true leaf stage. This lays the foundation for the potential size of the basket. Choose Eurostim Boron microfertiliser for quick and effective correction of micronutrient deficiencies in your sunflower crops.
Zinc — the growth engine for corn
If boron is the health of sunflowers, then zinc is the energy of corn. Corn is an indicator crop for zinc deficiency: it reacts to its lack immediately.
How zinc affects the result:
Auxin synthesis: Zinc is involved in the production of growth hormones. When it is deficient, the internodes shorten and the plant becomes ‘dwarf’.
Resistance to temperature stress: Zinc helps corn withstand sudden temperature changes and night frosts in the early stages.
Pollination and grain filling: This element promotes better grain formation in the cob and increases the weight of 1,000 seeds.
Comparison table of requirements: Sunflower vs Corn
Characteristic | Sunflower | Corn |
Key micronutrient | Boron (B) | Zinc (Zn) |
Critical phase | 4–10 leaves (budding) | 3–5 and 7–9 leaves |
Signs of deficiency | Cracks on the stem, deformation of the basket | White stripes on the leaves, growth retardation |
Effect of application | Full filling of the basket and seeds, high oil content | Fullness of cobs, grains, rapid moisture release |
Why are standard NPK fertilisers not effective?
Most traditional fertilisers are aimed at increasing vegetative mass. However, without micronutrients, plants cannot effectively absorb even the nitrogen present in the soil.
Blocking of elements: High phosphorus content in the soil often blocks the availability of zinc.
Soil pH: On carbonate or overfertilised soils, boron becomes unavailable to the root system.
That is why foliar feeding (leaf application) with chelated forms of micronutrients is the only way to quickly and effectively close the deficit in critical phases.
FAQ: Questions that farmers are most often interested in
- Can boron/zinc be mixed with herbicides?
Yes, most modern chelated forms are compatible with pesticides, but it is always worth testing for miscibility. Important: boron fertilisers can increase the pH of the working solution, which is critical for some herbicides.
- What is the optimal boron application rate for sunflowers?
The average rate is 100–150 g of pure boron per hectare per application. Organic forms (boron ethylamine) work best.
- How to determine zinc deficiency if there are no visual signs yet?
The most accurate method is tissue diagnosis of plants in a laboratory. A hidden deficiency can reduce the yield by up to 10% without any yellow spots on the leaves.
Conclusion: investing in micronutrients is a guarantee of profit
The use of boron on sunflowers and zinc on corn is not an expense, but a highly effective investment. In an unstable climate, these elements provide stress resistance, which separates a profitable farm from a loss-making one.
Need advice on choosing fertilisers for your soil type?
Contact our company’s specialists. We will help you develop a customised nutrition plan that will unlock the full genetic potential of your seeds.