For a long time, microorganisms were seen as villains in agriculture because they are related to agents that cause diseases in plants, however, over the years and thanks to advances in technology and research focused on understanding these microscopic beings, this view has changed drastically. .
Today it is possible to say that most organisms do not cause any type of pathology in plants, on the contrary, they still provide benefits to the ecosystem as a whole, from the soil to the final food produced.
Before we delve deeper into the benefits that microorganisms offer to plants, it is important to know a little more about them.
Life appeared on Earth more than 4 billion years ago in the form of microorganisms and, since then, these beings have evolved into countless species and strains. “They are the most diverse and abundant living beings on the planet and we, in fact, live in their world and they live in us”, says Johana Perez, Global R&D Product Design Manager at Tradecorp do Brasil.
We have more than 8 billion people in the world and each of us carries more than 100 trillion microorganisms in our body, the vast majority of which form beneficial associations that positively impact our organism, enabling the body to function fully, participating in processes such as digestion and modulating our immune system, even our mood. Johana states that no human being can live without microorganisms.
Microorganisms are represented by viruses, bacteria, protozoa and fungi.
Just as they are important to humans, microorganisms are also beneficial to plants. According to Johana, a single gram of soil carries billions of microorganisms that form, for the most part, beneficial associations with plants, such as helping to capture essential nutrients, in addition to fighting enemy micro and macroorganisms.
“Science didn’t know much about these microbes until recently, as they are difficult to study because they carry out their work so silently that they go unnoticed”, explains Johana.
New molecular biology technologies, such as Next Generation Sequencing, used only a couple of decades ago, have helped to identify thousands of these microorganisms and unravel their function in the rhizosphere and aerial part of plants.
Today, microorganisms are allies of rural producers and are used for biological nitrogen fixation, phosphorus solubilization and as pest and disease control agents, according to Tradecorp's technical coordinator, Fernando Bonafé Sei.
He explains that, currently, several species of microorganisms are used in agriculture, the oldest of which are biological nitrogen fixers, such as Bradyhizobium, which has been used in soybean cultivation for over 100 years.
Johana Perez explains that these types of microorganisms are known as endophytes (inside the plant) and the most used in agriculture are rhizobia, bacteria that colonize root cells forming nodules (little balls) responsible for fixing atmospheric nitrogen, acting as one of nitrogen fertilizer.
“In this way, it is possible to reduce nitrogen fertilization, mainly carried out with urea, reducing risks such as soil acidification, contamination by nitrate and heavy metals and also greenhouse gas emissions”.
Species such as Azospirillum and Pseudomonas have been recommended to improve soil fertility and nutrient availability. These species of microorganisms that colonize the rhizosphere act by solubilizing nutrients present in the soil in their insoluble and inaccessible form for plants, such as phosphorus, minimizing the need for phosphate fertilizer, generating sustainability for the production process and savings for producers.
Another important group of microorganisms used in agriculture are species capable of controlling pests and diseases. They are known as biocontrol agents, the best known are the genera Trichoderma, Bacillus, Beauveria and Metarhizium.
“Many species of fungi, viruses and bacteria of different strains are currently present in nutrition and biological control products sold in Brazil”, says Fernando Bonafé. Unlike typical chemical compounds used to control pests and diseases, biocontrol agents do not cause harm to the environment or human health.
This does not mean that there are no villains, a few species of microorganisms cause diseases in plants and animals, as well as in humans. Johana explains that, unlike beneficial species, when pathogenic microorganisms proliferate, the effect is immediate.
“In this sense, the farmer notices it straight away and that is why it is more common to hear about bad microorganisms, which make more ‘noise’, than the beneficial ones, which are more abundant, but more discreet”, he states.
Additionally, Fernando highlights that to avoid the use of microorganisms that could cause damage to environmental and human health, it is recommended to purchase products that are registered by MAPA (Ministry of Agriculture, Livestock and Supply).
Finally, it is necessary to point out that there are species that are beneficial and harmful to agriculture, as well as those that do not cause any effect to the plant, these are known as commensals. However, sometimes a commensal species can turn malevolent under certain conditions.
The best way to prevent species that cause damage to crops from proliferating is to maintain a balanced soil rich in beneficial microorganisms that are capable of controlling the multiplication of pathogens through their interactions.
In this sense, maintaining sustainable agricultural practices, reducing the use of chemical fertilizers and pesticides, it is possible to promote richer, biodiverse and healthier soil.
Balanced soil, as we mentioned previously, is essential to prevent the proliferation of harmful microorganisms. In this sense, Tradecorp's technical coordinator advises that it is necessary to adopt management techniques such as crop rotation using a mix of cover crops, direct planting, use of organic and organic-mineral fertilizers, in addition to the use of bio-inputs in the production system. .
In other words, all technologies that promote an increase in soil organic matter and the introduction of beneficial microorganisms will favor the soil's microbial community and its balance.
To conclude, Johana Perez states that the adoption of sustainable agricultural practices, where abundant food is produced efficiently, without depleting the planet's natural resources or contaminating the environment, is essential and possible. To achieve this, nature's principles of forming agricultural and livestock systems that are self-sustaining, just like nature itself, are applied.
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