To achieve correct and adequate nutrition in crops, it is essential to supply all the essential nutrients in the necessary quantities. The lack of any nutrient can cause serious problems causing disastrous consequences in crops.
Each of these nutrients appears in the soil in varying amounts. Iron, the micronutrient that plants need in greater quantity, is involved in numerous functions of their metabolism, such as chlorophyll formation or energy production, and is usually found in the soil in a concentration around 3.8%. Despite that high presence of iron in the soil, one of the most common problems is the iron chlorosis. It is an iron deficiency in the plant, characterized by interveinal yellowing of the youngest leaves. Crops that suffer from iron chlorosis have weak leaves that end up drying and falling, the fruits obtained are smaller and sometimes the damage produced is irreversible, causing the death of the plant.
For the plant to have the iron it needs for its proper development, it must be available in the soil, and, in addition, it must be transported to the roots for absorption and assimilation.
There are several factors that influence the possible availability of iron in the soil. One of the most important is the pH. Above pH 4, the availability of iron to the plant is drastically reduced since it precipitates in the form of oxides and hydroxides.
A high clay content, a low amount of organic matter in the soil, a high salinity, a high concentration of phosphates, etc. are other factors that can negatively affect the availability of iron in the soil, and, therefore, lead to the appearance of iron chlorosis since the plant is not able to take advantage of the natural way iron.
The use of chelating agents, such as iron chelates, are the best option to avoid iron chlorosis, since they are capable of keeping the micronutrient fully available by isolating it from the action of external agents. In addition, the use of iron chelates helps to increase the solubility of the metal so that the absorption by the plant is favored and the amount of assimilated iron is greater.
Another advantage of the use of fertilizers with iron chelates is that the chelating agent helps to make better use of the iron present in the soil naturally. When the iron chelate is added to the plant, it makes it easier for the iron that is bound to it to reach the plant. Once the iron has been absorbed, the chelating agent is free in the soil so, if the pH and concentration conditions are adequate, it can solubilize part of the iron previously existing in the soil, making it also reach up to the plants roots. The active principle of iron fertilizers is not only the metal that it contributes, but also the organic part that can mobilize native iron from the soil.
Therefore, iron chelates have proven to be an excellent choice as a source of iron to avoid iron chlorosis, making it possible for both the plant and the fruits to develop correctly.