Nitrogen is a mineral element that is very abundant in nature. It is considered to be the third most abundant element in plant tissues, after carbon and hydrogen. It is involved in the growth process and development of crops as it is an inherent component of proteins, coenzymes, nucleotides and chlorophylls. A deficiency in this element manifests itself in chlorosis due to the inhibition of chlorophyll synthesis. Nitrogen is the key element in the plant nutrition process. It is involved in the synthesis of proteins, chlorophyll and other major compounds that are important in plant metabolism. Nitrogen exists in several forms and plays a decisive role in the vegetative growth of plants. The most important part of soil nitrogen is in the organic state. This form is not absorbed directly by the plant roots and must be transformed into mineral nitrogen (nitric or ammoniacal) to be available. Ammoniacal nitrogen is a cation that can be captured by the soil's absorbent complex by inducing its low mobility in the soil. On the other hand, nitric nitrogen is an anion that is not too much retained by the clay-humic complex, which gives it great mobility in the soil and therefore a great risk of leaching by rainwater or irrigation.

Effects of nitrogen on crops

For example, poor nitrogen nutrition reduces the growth of the melon plant by 25% and reduces the number of male flowers by 35% and hermaphroditic flowers by 55%, even if the other elements are present in sufficient quantities. Nitrogen deficiency in melon cultivation results in a diffuse yellowing of the leaf blade and veins, and a small, elongated fruit that takes on a very light colour. However, over-consumption leads to excessive vegetative growth, weakens the plant, and can harm fruit set. Excess nitrogen also affects fruit storage.