A fertilizer is any type of organic or inorganic substance that contains nutrients in plant-assimilable forms, to maintain or increase the content of these elements in the soil, improve the nutritional quality of the substrate, stimulate plant vegetative growth, etc. Natural or organic examples of fertilizer are found in both classic manure, mixed with agricultural waste such as forage, and guano formed from bird droppings (for example, poultry, such as chicken manure).

Iron is the most abundant nutrient in almost all soils. However, iron deficiencies in crops are common due to its low solubility in soil and the high sensitivity of plants to iron chlorosis. The low solubility of iron in soil is a consequence of the high pH of calcareous soils (8-9), where the solubility of ferric oxides is minimal.

Furthermore, these soils are highly prevalent in bicarbonate ions, which, on the one hand, cause plants sensitive to chlorosis to decrease their ability to absorb iron and, on the other, clog the medium so that the pH cannot drop in the rhizosphere, preventing potential iron solubilization sites. If left untreated, iron chlorosis can cause complete defoliation of the plant, insufficient drainage, damaged roots, compacted roots, high alkalinity, and plant nutritional deficiencies.