The groups of Soil Science and Biochemistry, Proteomics and Biology of Plant and Agroforestry Systems of the University of Córdoba collaborate in a study published in Scientific Reports on the effects of phosphorus and zinc fertilization in the growth, yield and quality of the grain of corn.
Cereals like rice, wheat and corn they are used to feed the world’s population. In fact, represent 55 to 70% of the total calories consumed in some countries in Asia, Africa, Latin America and the Caribbean. The production and quality of these cereals depend to a great extent on the availability of nutrients such as phosphorus in the soil, but also on zinc.
In the Edaphology Unit of the María de Maeztu Excellence Unit – Department of Agronomy of the University of Córdoba (Dauco) have been studying the interaction of phosphorus and zinc in the soil for years (the latter a nutrient not very taken into account when fertilizing) for the nutrition of cereals. Adequate availability of both elements is key for cereals to absorb nutrients from the soil and, therefore, produce more and better food.
Analysis carried out
In this case, Dauco researchers Antonio R. Sánchez, Hasna Nechate-Drif, José Torrent and María del Carmen del Campillo have analyzed the fertilization with phosphorus and zinc in corn. For this, they tested various treatments on corn in 10L volume pots with different Mediterranean soils.
Regarding the analyzes carried out, the UCO details that in one treatment they added only phosphorus, in another only zinc and, in the third, a combination of phosphorus and zinc. In addition, they used a control treatment, without the addition of phosphorus or zinc. The fertility of the calcareous soils used was “low”, due to the high pH that limits the availability of these nutrients, as is typical in Mediterranean soils.
Although, normally, when only phosphorus is added in other cereals the plant usually produces a higher yield, in this case «it was a surprise to see that when you added only phosphorus it also impaired growth and performance», Points out the researcher Antonio R. Sánchez.
The best option in terms of corn growth and yield was, therefore, the combination of phosphorus and zinc. Nevertheless, the research team wanted to go further, delving into the quality of the grain and, for this, it had María Dolores Rey, María Ángeles Castillejo and Jesús V. Jorrín, researchers from the Biochemistry, Proteomics and Biology of Plant and Agroforestry Systems group of the UCO.
This group used proteomics (large-scale study of proteins), due to its experience in this field and its suitability for the analysis of the quality of the corn grain since, in nutritional terms, corn kernels are composed mainly of starch (70%) and proteins (10%), and their quality depends largely on their protein content and composition.
«In corn, the main proteins are prolamines (also known as ‘zeins’), albumins, globulins and glutamines. The zein fraction represents about 60% of all proteins; however, they are the ones that contain the least nutritional value for humans due to the absence of essential amino acids such as lysine and tryptophan. One of the main objectives in a corn improvement program is to increase these essential amino acids, which can be achieved with a correct supply of specific nutrients, as has been observed in the present study “, explains researcher María Dolores Rey.
Results obtained
Therefore, after the analysis of more than 1,700 proteins they focused on search the grains for corn from the different fertilization treatments those proteins described as “quality enhancers” and found that the treatment in which only zinc was added was the one that gave the highest quality protein content of the grain.
However, the second treatment in terms of protein quantity and grain quality was the one that combined phosphorus and zinc fertilization. Thus, both agronomically, in terms of corn production and yield, as well as grain quality, the combination of zinc and phosphorus in corn was the best of the tested options.
According to this study, the combination of phosphorus and zinc is the best fertilization option for corn in Mediterranean soils despite the fact that zinc is normally a neglected nutrient in our area.
The optimization of the use of fertilizers and the application in a sustainable way, but with positive results in terms of production, yield, growth and grain quality It is one of the challenges of the Dauco Edaphology Unit in search of a more sustainable agriculture.
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