Nitrogen and nitrogen fertilization - the recommendations of agronomists!

As an essential nutrient, nitrogen has a great influence on the growth, development and productivity of plants. Precisely for this reason, it is essential that the fertilization with it be precise and with the optimal amount, which is calculated on the basis of the soil analyzes carried out, the requirements of the crop and the desired yield from it.

The agronomists at NIK Agro Service provide expert opinion on the role and importance of nitrogen and how we can de-dust the nitrogen fertilization process to achieve better results with less cost.

What is the importance and role of nitrogen in plant development?

Healthy plants contain 3-5% nitrogen in their aboveground organs. Of all the nutrients that have a role in fertilization, nitrogen is of the highest concentration and is therefore essential for the nutrition and development of plants.

Nitrogen is a major component of chlorophyll, through which plants photosynthesize and produce sugars from water and carbon. It is also an essential component of amino acids, the basic building blocks of proteins. Without protein, plants die.

Some proteins are structural units of the plant cell, while others act as enzymes, making possible many of the biochemical reactions on which life is based.

Last but not least, nitrogen is an important component of nucleic acids,DNA is the genetic material that allows cells and whole plants to grow and reproduce.

In short — nitrogen is critical to achieving satisfactory yields and also directly affects the protein content of plants.

What are the factors that affect the nitrogen content of the soil?

In soil, nitrogen is found in three main forms:

• in the form of organic matter
• ammonium (NH₄⁺) ions
• nitrate (NO₃-) ions

Nitrogen, which is incorporated into organic matter, needs to be transformed before it is available to plants.

The nitrogen available to plants is in inorganic form— ammonium and nitrate ions, which are often called mineral nitrogen.

Nitrogen cycle

Photo source: Cornell University

Nitrogen can go through many transformations in the soil — the so-called nitrogen cycle.

The essence of the nitrogen cycle consists in a series of transformations of inorganic nitrogen into organic (immobilization) and vice versa (mineralization). These processes occur under the influence of microorganisms, and their rate is higher on warm and moist, but not waterlogged soils.

The amount of inorganic nitrogen that is available to plants often depends on the balance between these processes.

The ammonium ion, which is not immobilized or absorbed by plants, quickly turns into a nitrate ion. This process occurs quickly in well-aerated soils. For this reason, in the soil we find more nitrate ions than ammonium ions.

There are several ways in which plant-digestible nitrogen can be lost.Nitrite nitrogen is more susceptible to losses compared to ammonium. The following processes can lead to significant losses:

• washing
• denitrification
• Evaporation
• export with the production

The nitrate form of nitrogen is so soluble that it is easily washed out when an excessive amount of water passes through the soil. This is the main route by which nitrogen is lost from light sandy soils, which are easily washed out.

However, leaching is not a serious problem in heavier, clay and impermeable soils, where water passes through the soil profile very slowly. On the other hand, these soils are easily waterlogged, and when microorganisms use up the oxygen in the soil, they begin to consume the oxygen from the nitrates. In this process, nitrates are transformed into a gas — nitrogen dioxide or nitrogen, which is inaccessible to plants. Losses can be significant when soils are warm and remain waterlogged for more than a few days.

Ammonium nitrogen losses occur less frequently and are mainly from fumes. This mechanism of losses is of particular importance in alkaline soils.

The export of nitrogen with the production also represents a loss, because the nitrogen in the plants is completely exported outside the field. Nitrogen in plant residues flows back into the circular, and it is better to think of as immobilized than exported. Much of it is likely to be mineralized and absorbed by plants.

How much plant-accessible nitrogen is there in your field?

What is the amount of nitrogen available to plants is most accurately established by laboratory analyzes. In order for the correct conclusions to be drawn, the representativeness of the soil samples formed is of paramount importance.

Therefore, determining the number of samples and their recruitment is good to be done by specialists in the field. Thus, the quality of the results obtained is ensured, on the basis of which the right decisions can be made.

Farmers who checked before fertilizing

Agronomists from NIK Agro Service monitor and analyze changing climatic conditions and the impact they have on farmers' businesses. That is why they decided to check what are the amounts of mineral nitrogen left in the soil, in conditions of varying degrees of drought and unsatisfactory yields obtained.

Image from crop monitoring program — GeoScan showing different levels of nitrogen content

What happens to nitrogen imported but not absorbed by plants?

For this purpose, block sampling was carried out on three farmers, where significant amounts of residual mineral nitrogen were found to be present at the first sampling. The sampled fields are located in different areas of the country, affected to varying degrees by drought. The sampling was carried out at the end of September, about two months (for Clients 1 and 2) and about one month (for Client 3) after the initial sampling.

Comparative table of the results of three farmers from different parts of Bulgaria for the presence of nitrogen in the first and second sampling.

Repeated sampling and analyses confirmed the presence of significant amounts of residual mineral nitrogen, which remained at relatively the same levels.

Nitrogen has not been subjected to processes leading to losses in the post-harvest period and is available for autumn crops to be sown.

Thanks to this information, farmers will reduce the doses of fertilizers for autumn application, and some of them will completely skip autumn fertilizing,without worrying that they will put their crops in conditions of hunger, because they know what they have.

Thus, these farmers can make a reasoned decision not to spend on fertilizers that the plants do not need.

Find out more about agronomic services of NIK Agro Service, with which you can see how much unabsorbed stock is in your soil and optimize fertilization costs!

Or contact the NIC team for complete information!