Have you ever imagined facing an illness, being weakened and suffering from nutritional deficiencies? In a situation like this, microorganisms are more likely to have a significant impact on our health. The same happens with plants, which constantly suffer attacks from fungi, bacteria and viruses. When nutritionally imbalanced, plants are unable to effectively combat the entry of these pathogens, resulting in considerable damage. For grain crops, this can translate into losses in final productivity.
In addition to soil fertilization, foliar application of nutrients can boost plant health, strengthening their defenses against pathogens and improving their ability to resist diseases. In this article, we will explore the benefits of this technique and highlight the essential nutrients for foliar nutritional supplementation.
One of the promising methods to increase plant health is the induction of resistance using mineral nutrition. It involves the activation of natural defense mechanisms, which make plants more resistant to pathogens. This resistance is achieved through modifications in the anatomy of plants, such as the development of thicker, lignified or silicated epidermal cells, which act as physical barriers that inhibit the entry of pathogens.
Furthermore, the induction of resistance also acts on the physiology and biochemistry of the plant, stimulating the production of toxic substances or creating unfavorable conditions for the growth of pathogens. An example of this type of substances are phytoalexins, which are secondary compounds produced by the plant in response to infection by microorganisms or stresses (physical or chemical).
Plant nutrition is a factor that can easily be manipulated and, if correctly used, can serve as a complement in disease management. However, more in-depth knowledge is needed about which nutrients can be used and in which scenarios we will achieve greater responses.
Starting with macronutrients, which are the essential nutrients that plants need in large quantities: they are normally supplied to the plant via the soil, however, we can also use them in foliar supplementation:
•Nitrogen: plays a fundamental role in the vegetative growth of plants, stimulating the production of new and healthy leaves, through the production of chlorophyll, increasing the efficiency of photosynthesis and production of amino acids, proteins, hormones and phytoalexins. However, the effect that can happen when there is excess nitrogen in the leaf deserves to be highlighted. This situation can favor the attack of pathogens, since the tissues can become more tender, facilitating the infection process.
•Phosphorus: plays a fundamental role in the production of energy (ATP), and in the synthesis of compounds vital for plant growth, such as proteins, vitamins and polyphenols.
•Potassium: acts in regulating the plant's water balance, activating enzymes and transporting other nutrients. Potassium is described in the literature as the nutrient that most influences the severity of diseases, as it can act to increase the thickness of the cell wall, provide greater tissue rigidity and rapid recovery after injuries.
•Calcium: acts to strengthen the cell wall of plants, helping to provide a physical barrier against the entry of pathogens.
Micronutrients are required in smaller quantities by the plant and play an essential role in physiology and growth. Some micronutrients such as zinc, manganese, iron and copper act to activate enzymes and strengthen the plant:
•Zinc: is involved in the production of hormones and enzymes, in addition to influencing the fertility of pollen grains.
•Manganese: activates enzymes involved in defense against pathogens and photosynthesis metabolism.
•Iron: acts in the synthesis of phytoalexins, is a constituent of proteins and also acts in cell division.
•Copper: acts in the activation of some enzymes, in the formation of the cell wall, in the synthesis of DNA and RNA and in the metabolism of proteins and phenolic compounds. In addition to acting in the production of compounds that induce resistance to pathogens, such as lignin.
Another nutrient considered beneficial, which plays a fundamental role in inducing resistance to diseases, is Silicon. It exerts multiple functions, including the formation of a physical barrier below the leaf cuticle. This layer of silicon increases tissue rigidity and strengthens cells, making them less susceptible to attack by pathogens.
It is essential to highlight the synergy that exists between nutrients. A healthy plant needs to be adequately nourished, avoiding both deficiencies and excesses of nutrients. Once this criterion is met, it is possible to employ some of the nutrients mentioned above to enhance the control effects.
The use of foliar nutritional supplementation in grain crops opens up new opportunities to ensure plant health and increase productivity. Through the correct application of nutrients via the leaves, plants can develop better and resist stress and diseases. However, it is crucial to have the help of a specialist professional to ensure the effectiveness of this strategy.
In summary, foliar nutritional supplementation is a promising approach to increasing plant health and preventing disease. By providing essential nutrients through the leaves, plants are strengthened, acquiring greater resistance to pathogens and improving their overall performance. Integrating foliar nutrition with other agricultural management practices can bring significant benefits, such as reducing environmental impacts and costs. Therefore, consider this strategy as part of a comprehensive crop management program for healthier, more productive results.
