Nitrogen fertilizers, what they are and how they work

THE nitrogen fertilizers are those rich in nitrogen. The latter is one of the three nutritional macroelements, the others are phosphorus and potassium, which plants have a particular need for their growth. In this article we will see in which substances the nitrogen used as fertilizer is contained: to get to know this element and better understand the product labels.

Nitrogen: where it is found and what it does

Nitrogen reaches plants in various ways. For example, through the rain and wind that drag the nitrogen present in the atmosphere; or by 'capture' from the atmosphere by particular microorganisms called nitrogen-fixers which are provided by many plant species (in particular legumes); or even through the decomposition of leaves or other organic substances that naturally reach the ground. Another way is the administration of nitrogen fertilizers both organic and mineral by man.

Nitrogen stimulates the growth of plants and the signal of its balanced presence in a plant is the beautiful dark green color of the leaves. However, if nitrogen is present in excessive quantities and in an immediately assimilable form (as in the case of nitric nitrogen), the plants are excessively stimulated to development and this decreases their resistance to disease.

Artificial and natural nitrogen fertilizers

Whether they are natural or artificial, beware of excess 'sprint': considering that, as we said before, nitrogen can already naturally reach plants, you shouldn't overdo it with natural nitrogen fertilizersor artificial as they are. The species that benefit from more than one nitrogen fertilization they are house plants and lawns (in spring fertilization), which have limited possibilities to intercept nitrogen in a natural way.


It's a nitrogen fertilizer artificial or natural, according to its production. It has a particularly high content of nitrogen (about 45%). It is used both in granules and dissolved in water (in the dose of 10 grams per 10 liters of water), making sure to distribute it only on the soil. Contact of urea with leaves, stems and flowers should be avoided because it could cause burns.

Calcium cyanamide

It is a particular artificial fertilizer that, in addition to providing nitrogen, is used to decrease the acidity of the soil and as an adjuvant in the fight against fungi and insects. It is produced from limestone, coal and pure nitrogen obtained by separation from the air. It contains about 15% nitrogen, 15% powdered coal and 30% quicklime and calcium carbonate.

Ammonium sulphate

It has the appearance of a white salt and contains about 20% nitrogen. Its characteristic is that it is easily retained by some components of the soil, which makes it slowly assimilated by plants and available longer. For this reason it is used in 'slow release fertilization', even in advance of the optimal period of nitrogen use by plants. A classic is the winter fertilization of fruit and vegetable plants.

Sodium Nitrate

It contains 15.5% nitrogen and, unlike ammonium sulphate, is readily absorbed and assimilated by plants. It can be used for an immediate result, but great attention must be paid for two reasons. First, because excessive and too rapid assimilation can weaken the plants; second, because the nitric ion is easily dispersed in the soil and the excess sodium leaves residues that are harmful for some plants as well as polluting the water tables.

Calcium nitrate

It is industrially obtained from the processing of lime with nitric acid. The nitrogen content is the same as sodium nitrate and is normally preferable to the latter because it does not leave harmful residues in the soil. Calcium nitrate is also a nitrogen fertilizer with a quick effect, but the plants also use calcium. This feature makes it unsuitable for fertilizing acidophilic plants.

Ammonium nitrate

It is a double-acting, fast-slow fertilizer, because it is composed of nitric nitrogen (immediately assimilable) and ammonia nitrogen (with slow assimilation. Compared to sodium and calcium nitrates, it must be distributed in higher doses and more rarely because the effect is less intense and more prolonged over time It contains nitrogen in percentages which, depending on the products, range from 15% to 26%.

Nitrogen fertilizers: where to buy

Once you have chosen the one that best meets your needs, you may need to know that some of these nitrogen fertilizers they are contained in fertilizer products that can be purchased both in agricultural consortia and by exploiting the Amazon purchase.

To cite some examples, on “this Amazon page” you can find a great selection of mineral Urea.

For the other fertilizers mentioned:

  • Calciumanamide (several offers available)
  • Calcium nitrate (all products on the market)
  • Ammonium sulfate (we have reported the best Amazon price)

Video: Frame William Enhanced Efficiency Nitrogen Fertilizers: What are they? Why use them? (May 2021).