A team from the Department of Agronomy of the UCO have demonstrated, with field trials carried out during eight agricultural seasons, which spraying the fertilizer on the plants further increases the zinc concentration in wheat than if it is applied on the ground.
The micronutrient deficiencies suppose problems in human health for a third of the world’s population. Worldwide, the zinc deficit is more problematic in rural areas of developing countries, where the diet is reduced to the intake of vegetable products grown on soils with low nutrient availability.
Eight years of study
In this context, biofortification, which is the process of increasing the nutritional value of crops through an increase in the concentration of minerals or vitamins, is revealed as a remedy to this problem.
In the search for solutions, the Edaphology Unit of the María de Maeztu Excellence Unit – Department of Agronomy of the University of Córdoba (Dauco), headed by the researcher Antonio R. Sánchez Rodríguez has searched for eight years for the best zinc biofortification strategy for wheat grown on calcareous soils in southern Spain.
Between 2012 and 2019 this team tested different methods to biofortify wheat in eleven field trials established in soils with zinc deficiency. On the one hand, the effect of applying different doses of fertilizer to the soil (up to ten kg per hectare) and, on the other, the results of applying different doses of zinc by spraying to the plant in various phenological stages of wheat were evaluated.
The application: after the start of harrowing or in flowering
In this context, «the application on the ground turned out to be ineffective, while the foliar application was revealed as a very efficient strategy to increase the zinc content in the plant, increasing the concentration in grain up to 50% “, says the researcher.
«It was, in this way, much more effective foliar application, because with a tenth of the product (1.28 kg per hectare) better results were obtained, than with the application to the soil, ”says Sánchez.
Thus, «taking into account the variety of wheat, this direct application to the plant was more effective when it was applied after the start of the canopy or in flowering», Assures the UCO researcher.
Feeding the plant, and not the soil, is thus presented as a strategy to face the problem of zinc deficiency in calcareous soils short term. In addition, if at some point wheat were paid for its nutritional content, the farmer could see his economic benefit increased.
This solution «is very interesting for places where there is no other source of zinc in the diet, although it would imply adding an additional field work in the wheat crop or combining it with the application of other phytosanitary treatments»Remembers Sánchez.
Predicting Wheat Yield to Zinc Fertilization
In this work, the team from the Edaphology Unit also looked for a soil indicator that would help predict the yield response of durum wheat to zinc fertilization. However, they found that “under field conditions it is very difficult to obtain this parameter and that a simple indicator cannot predict this response.”
However, the researchers assure that «while at the laboratory level it was possible to define some indicators, in the field this task is difficult since it is highly dependent on factors such as precipitation and many more years of study would be needed, “concludes the UCO in a statement.
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