Corn fertilisation and particularly nitrogen fertilisation is a major element of crop productivity. To adjust the inputs in order to maximise the agronomic and economic efficiency of fertilisers, it is necessary to know the needs of the plant, the period of growth to which its needs correspond and the contribution of the soil.
PHOSPHORUS AND POTASSIUM
Among its main requirements, corn absorbs potassium. Phosphorus has a good effect on the development of corn in the early stages and in the flowering phase, while potassium is important throughout the growing season, controlling the water balance of the plant.
Maximum uptake of the main nutrients is highly varied and takes place in the following phases:
- Potassium - 7-8 weeks after emergence
- Phosphorus - 9-11 weeks after emergence
- Nitrogen - 7-9 weeks after emergence
For example, with an average annual grain yield of 7.5 t/ha, in the balance of nutritional needs of corn cultivated in monoculture, approximately 7-10 kg P2O5 and 50-60 kg K2O/ha should be taken into account. The fertilisation dose of these components at average fertility, taking into account the inflow from plant residues, is 60 kg P2O5/ha and 100 kg K2O/ha.
Three stages of nitrogen fertilisation:
- determination of nitrogen dose
- setting the date of application
- fertiliser selection
The choice of nitrogen fertiliser requires consideration of several options to optimise the plant’s use of nitrogen.
Corn reacts very well to nitrogen fertilisation in wet years, but negatively to fertilisation with nitrogen in dry years. The lower the uptake of potassium and phosphorus, the greater the negative reaction.
During its development, corn efficiently absorbs the ingredients contained in manure or slurry. Phosphorus and nitrogen demand is highest in the summer months. The fertilising value of minerals in an organic fertiliser in the year of application is determined using the so-called fertiliser equivalent. Fertilisation factors make it possible to calculate of the total amount of a given ingredient that is used by the plants.
FERTILISATION WITH MAGNESIUM AND SULPHUR
When deciding to grow corn, make sure that the soil is moderately rich in magnesium and sulphur. Deficiency of these elements can significantly contribute to slower plant development. In the absence of organic and natural fertilisation, it is recommended to use sulphur and magnesium corresponding to 25 to 75% of nutritional needs.
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