Is it worth investing your finances, time, and effort to work out a fertiliser application plan? The answer is definitely yes! By starting off the season with correctly balanced basal fertiliser and following up with timely side-dressing, you can help your crops reach their potential. But what is balanced fertilisation?

Every grower knows that a plant builds its body with “blocks” – chemical substances collected from the environment, like carbon from the air, and water and minerals from the soil. The sun provides crops with the energy to drive the long chain of transformations to produce carbohydrates, proteins, fats, and fibre, all valuable constituents of yield and ultimately food for humans and animals.

It is a well-known fact that nitrogen is the most important, but also the most limiting of 17 essential plant nutrients. Nitrogen is the main constituent of proteins. Its supply determines the plant’s growth, vigour, and yield. Nitrogen is highly mobile in soil, which makes it prone to volatilisation and leaching.

Nitrogen is also demanded by micro-organisms. However, one should not just confine oneself to nitrogen fertiliser. In reality, the efficiency of each applied kilogram of nitrogen fertiliser is directly related to sufficient availability of other nutrients, particularly potassium. The effect of the application of potassium-containing fertilisers might be masked by the response from nitrogen, especially during the initial stages of growth.

Vigorous growth and intensification of green colouration of leaves are the consequences of using nitrogenous fertiliser alone, but also in combination with potassium. Nevertheless, the role of potassium in crop production is difficult to overestimate. Potassium is a key element to water balance in plants, which drives their vigour. The availability of potassium in crop tissue provides a synergetic (mutually beneficial) effect on nitrogen, increasing its assimilation.

Potassium is associated with root growth, transport of nutrient compounds between different plant organs, crop quality and crop resistance to lodging, disease and drought. It is crucial to apply mineral fertilisers containing the primary nutrients, N, P and K, as without them, crops are forced to mine them from soil pools. These natural sources are prone to depletion due to yield collection year on year, which inevitably leads to dramatic decrease of soil fertility and lowers the output.

A balanced crop nutrition approach is crucial to provide the right ratio of nutrients throughout the growing season, according to crop requirements and soil conditions. The correctly designed fertiliser programme should be based on the results of soil analysis and yield target (nutrient removal). It should therefore consist of basal fertiliser and in-season top-dressing. For instance,at planting time, the farmer may apply fertiliser with a low nitrogen and high phosphorus and potassium content, which provides only small quantities of nitrogen to prevent losses and meets 100% and 70 to 100% of phosphorus and potassium demand, respectively.

Compound NPKs (like NPK 10:20:20 or PK 10:26:26), containing all three primary nutrients in each granule, might be of good fit, and separate sources and potassium chloride (MOP) will also do the trick. The side-dressing might include only nitrogen, or a combination of one with MOP, depending on the crop and yield goals.

More information about field tests is coming up in the next issues and at our website, www.ufertilizers.com.