Zinc deficiency, along with a lack of Vitamin A, is the most widespread in the world (Cakmak, McLaughlin and White, 2017). One of the causes of this is that widely consumed cereals tend to contain low levels of this mineral. In this regard the calcareous soils prevalent in the Mediterranean environment tend to present pronounced zinc deficiency, leading to negative effects on plant growth and, therefore, on the foods that ultimately reach consumers.
With the aim of solving the problem of zinc deficiency, a few years ago the Edaphology Unit at the María de Maeztu Excellence Unit - Department of Agronomy (DAUCO) began to study the effects that this deficit had on cereals.
As a result of this work, DAUCO professors María del Carmen del Campillo and José Torrrent, along with researchers Daniel Sacristán and Adrián González, found the 'magic number': the optimal relationship between phosphorus and zinc for the growth of corn in Mediterranean soils.
Taking into account that phosphorus tends to intensify the negative effects of zinc deficiency, the researchers looked for the balance between phosphorus (an essential nutrient in which the agricultural sector is very interested) and the zinc available, since fertilization with an excess of phosphorus has negative effects.
They were seeking to determine how much phosphorus caused zinc deficiency to worsen, affecting corn yields, in order to establish the limit that should not be exceeded.
Thus, an experiment was carried out with 20 different soils (six non-calcareous and 14 calcareous) featuring different levels of zinc deficiency. Phosphorus was added in order to verify the relationship between the two elements resulting in the best corn yields.
They found that the ideal ratio between these two nutrients is in a range of 30-60. Thus, the application of phosphorus and zinc fertilizers in soils with this deficiency should aim to increase the levels of the two nutrientsavailable, while balancing them in the right proportion for optimal plant performance.
This work shines a light on more sustainable, higher-precision fertilization in which exactly what the plant needs is added to the soil, but without overdoing it, seeking not to upset this balance while reducing costs for the agricultural community and increasing the yields of their crops.
In short, knowing the soil well and studying the nutrients as a whole, also taking into account their relationship, results in a more complete perspective and allows for more sustainable and profitable fertilization.
Sacristán, D., González‐Guzmán, A., Torrent, J. and del Campillo, M.C. (2021), Optimum Olsen Phosphorus/ZincDTPA ratio for the initial growth of maize in agricultural soils of the Mediterranean region. J SciFoodAgric. https://doi.org/10.1002/jsfa.10940