Current options for replenishing nutrients in winter wheat
2026. October 15., Thursday
2026. October 15., Thursday
Early to mid-October is the optimal sowing time for winter wheat. However, those who have not yet applied fertiliser need not despair. This is because Genezis NPK fertilisers, which are primarily designed to replenish phosphorus and potassium, have the advantage that, thanks to the irregular shape of the granules and the manufacturing technology, their active ingredients dissolve even when soil moisture levels are low, and dissolve more easily and quickly than NPK fertilisers with harder granules.
Each granule contains the same active ingredients and has good spreadability, ensuring an even distribution of the active ingredients across the field. Thanks to its excellent and rapid solubility, it is suitable for meeting wheat’s phosphorus and potassium requirements either in a single pass with sowing, as a starter fertiliser, or – if the seed drill is not suitable for this – by application immediately before sowing.
It is important to note that phosphorus is the driving force behind intensive root development and tillering. Winter wheat is a phosphorus-demanding crop; to achieve a yield of 8 t/ha, it takes up 88 kg of available phosphorus from the soil. By the time tillering is complete in autumn, the wheat has already taken up one-third of its total phosphorus requirement. Winter wheat continuously takes up phosphorus throughout its entire growth cycle, the rate of which follows the rate of dry matter accumulation. In the early vegetative stage, up to the point of tillering, wheat takes up phosphorus slowly during root formation. However, this initial uptake is critical for root development and tillering. From stem elongation to flowering, phosphorus uptake accelerates, and remains continuous during the grain filling and ripening stages. Drought reduces phosphorus mobility on the one hand, and impairs root function on the other. As phosphorus is immobilised in the soil and its uptake is greatly influenced by soil moisture content, if the soil dries out, this significantly reduces root phosphorus uptake, even when the available phosphorus content is high. Furthermore, drought reduces root mass, restricts longitudinal root growth and the number of root hairs, thereby limiting nutrient uptake. Thus, proper phosphorus nutrition is of paramount importance during drought. If the plant is unable to take up sufficient phosphorus, the wheat’s flowers will die off. This results in a clear reduction in yield. Furthermore, phosphorus increases chlorophyll content and protects leaf structure, enabling the wheat to maintain photosynthesis and dry matter accumulation even in the event of water shortage. An adequate supply of phosphorus results in a deeper root zone, enabling the wheat to access water and nutrients stored in deeper layers.
Wheat also has a high potassium uptake, amounting to 144 kg/ha for a yield of 8 t/ha. Up to the tillering stage, wheat’s potassium uptake is relatively moderate, but the potassium concentration in young plants is at its highest at this stage. This stage lays the foundation for frost tolerance and cell wall flexibility. The truly critical stage lasts from stem elongation to ear emergence; after this, potassium uptake ceases almost entirely. At the same time, it must also be borne in mind that on sandy loam soils, higher levels of autumn and winter rainfall can leach potassium (and sulphur too) below the root zone; therefore, it is even more important to establish a root zone of sufficient depth. The nutrient replenishment required for this is not limited to adequate phosphorus fertilisation, as magnesium and nitrogen replenishment, and indeed calcium supply, also have a significant influence on it. Potassium is responsible for the functioning of the plants’ stomata; therefore, early, intensive uptake directly determines the wheat’s resilience. Furthermore, it aids in the synthesis of cellulose and lignin, which is essential for protection against lodging. In the event of a dry spring, potassium helps maintain turgor in the cells, enabling the wheat to tolerate the heat better. Finally, cells well-supplied with potassium have thicker walls, making it more difficult for fungal diseases (rust, powdery mildew) to attack the plant.
It follows from the above (as the demand for PK arises as early as autumn and becomes more intense in early spring) that phosphorus and potassium should be applied as base fertilisers in autumn, before sowing. NPK fertilisers are best suited for this purpose, and the choice should be based on the nutrient status of the soil and the plant. Furthermore, some NPK fertilisers also contain calcium, magnesium and sulphur, which are equally essential for the development of wheat. Generally speaking, NPK 10-20-10 and NPK 10-20-5 are suitable fertilisers. However, where potassium levels are low and phosphorus levels are good or very good, a potassium-rich formulation such as NPK 8-16-24 is preferable; conversely, where potassium levels are good and phosphorus levels are lower, the use of NPK 8-15-15 or NPK 4-24-24 is recommended.
Although the above NPK fertilisers contain nitrogen and, depending on their composition, calcium, magnesium, sulphur and even boron, the quantities of these (which, of course, also depend on the application rate) fall short of the requirements of wheat.
As we need to ensure that the amount of nitrogen the crop will use up by spring (until top dressing) is available by the time of sowing, if we have not applied at least 35 kg/ha of nitrogen via NPK, it is advisable to make up the shortfall with a starter fertiliser. Depending on the circumstances, there are several suitable products available for this purpose. For the simultaneous replenishment of nitrogen, calcium and magnesium, Pétisó – which does not acidify the soil – and Green Max – which raises the pH of acidic soils and provides more calcium and magnesium – are the most suitable. With 100 kg of Pétisó per hectare, approximately 12 per cent and 10 per cent of the wheat’s calcium and magnesium requirements respectively can be met; with the same nitrogen dose, Green Max can supply half and one-third of these requirements respectively. The remainder can, of course, be covered by the calcium and magnesium content of NPK fertiliser, or by Pétisó or Green Max applied as a top-dressing. Soil pH also significantly influences the uptake of nutrients. In acidic soils, as little as half of the applied phosphorus is utilised, whilst the uptake of nitrogen and potassium may also decline – by as much as 23 per cent at a pH of 5.5. This level of nutrient loss cannot be ignored from an economic perspective. For the reasons outlined above, we recommend Pétisó where the aim is to prevent further soil acidification or to provide a modest replenishment of calcium and magnesium, and Green Max where we wish to remedy soil acidification or need to replenish larger quantities of calcium and magnesium.
If, when applying starter fertiliser, we wish to replenish calcium and sulphur rather than nitrogen, the solution is Pétisó+S 24-12 or Pétisó-S Max 20-18. The former provides less, whilst the latter provides more calcium and sulphur to our wheat, whilst maintaining the same nitrogen dose. Of course, these granulated fertilisers, which also contain sulphur, are suitable for top dressing; so, if we opt for calcium and magnesium supplementation (Pétisó or Green Max) in the autumn, we still have the option of using Pétisó+S 24-12 or Pétisó-S Max 20-18 in the spring to simultaneously replenish nitrogen, sulphur and, to some extent, calcium simultaneously as a top-dressing.
The best nutrient replenishment strategy is always to ensure balanced nutrient ratios tailored to the plant’s needs, not only in terms of nitrogen, phosphorus and potassium, but also calcium, magnesium and sulphur. Of course, this is not the end of the story, but an effective way of replenishing microelements is foliar feeding, which is not currently an option. (x)
Dr Csaba Varga
Technical Adviser and Senior Research Associate
Nitrogénművek Zrt.