Rice seeds treated with Azospirillum bacteria presented roots that were 86% longer than those of non-inoculated plants The roots treated with the bacteria also had a 100% increase in volume. In corn, Azospirillum provided greater length, diameter, volume and dry mass of the roots. Serratia bacteria applied in seeds and soil generated a 17% increase in rice productivity This microorganism potentiates the action of nutrients nitrogen, phosphorus and potassium. Rice plants treated with Serratia presented up to 60% fewer diseases, such as brown spot, sheath blight and rice blast. In beans, association of Serratia bacteria with Trichoderma fungi increased grain productivity in 17%. A series of studies carried out with different rhizobacteria (bacteria that act on the root) has shown that some microorganisms can be important allies of agriculture. They work by improving the plant's physiological processes, which promotes better nutrient absorption or facilitates nutrient availability. The result is larger, more disease-resistant plants with higher productivity. With the constant increase in fertilizer prices, the use of these biological inputs can mean important savings for the farmer. These experiments proved important gains in rice, beans and corn crops. In a study conducted by Embrapa Rice and Beans, the effect of soil bacteria on upland rice plants was measured. The work used prior knowledge about six types of microorganisms that are known to promote benefits for agricultural crops, but that are still little studied with the cereal. In laboratory, for each of these selected bacteria, a solution was made that was applied to rice seeds in a process called microbiolization. In culture media in test tubes, seedlings were developed that, when analyzed with the help of processing equipment and image assessment software, showed promising results such as greater initial establishment and better root development. In tests, the rice seedlings' roots that were treated with a type of bacteria called Azospirillum were 86% longer than the control treatment, which received no microorganisms. Besides, in comparison, there was also an increase of more than 100% in root volume. According to one of the study's coordinators, researcher Adriano Nascente,from Embrapa, this may mean the higher capacity of absorbing nutrients from the soil for the plant, which can positively impact productivity. Another study, coordinated by Nascente and akin to that carried out with upland rice, was conducted with corn crops with similar results, also obtained in a controlled cultivation environment. The Azospirillum microorganism provided higher values in length, diameter, volume and dry mass of the roots, in addition to dry mass of shoot system and total dry mass compared to the control treatment (without the bacteria). Researcher Adriano Nascente highlights work with multifunctional microorganisms The scientist says that it has already been proved in laboratory that, in addition to Azospirillum, other rhizobacteria of the Bacillus, Burkholderia and Serratia genera can generate greater root development in soybean, rice and corn plants (see study). These microorganisms have provided an increase of 24% to 31% in root length in flood-irrigated rice plants. From the laboratory to the fields Progressing research stages from studies previously carried out in laboratory to field situations are also important to better understand how complex biological interaction mechanisms work, combined with management practices. In another study, Nascente's team assessed different combinations of Serratia, a bacterial genus, with different doses of nitrogen, phosphorus and potassium (NPK) in upland rice experimental areas in Capivara Farm, an Embrapa property located in Santo Antônio de Goiás, Goiás, Brazil. The goal was to maximize the effect of these macronutrients through their association with the microorganism. In this case, the seeds also underwent the microbiolization procedure before sowing and, at days seven and fifteen after planting, the soil was sprayed with the liquid mix with Serratia that had been previously prepared in the laboratory. The result of three harvests was an average productivity increase in 17% (about an extra 630 kilos per hectare, considering the total production of 3,700 kilos per hectare) in the places where the bacteria was present in comparison with the area that did not have the microorganism treatment. The average increase in grain productivity for each macronutrient combined with Serratia bacteria was 16% for potassium, 17% for nitrogen and 23% for phosphorous. In relation to this last element, an important fact occurred that caught the researchers' attention: there was no difference in grain yield for Serratia treatments with and without phosphate fertilizers. This suggests that a benefit was provided by the microorganism. Researcher Marta Cristina Corsi de Filippi, who took part in this study, explained this evidence. "Serratia bacteria secretes organic acids and enzymes capable of transforming phosphorus already found in the soil into forms that are soluble and capable of being absorbed by rice plants' roots. Thus, we can consider that the phosphorous content that already existed in the area before planting due to previous fertilization but was unavailable to the plants, equated to a supply that was made available to the crop when the Serratia bacteria’s biological activity took place", the scientist details. Art: Fábio Noleto, translated by Mariana Medeiros According to the researcher, the perspectives are very positive, because this study with Serratia can generate a commercial product. 'We are working in partnership with the private sector. As a consequence of this partnership, we will have a commercial product, which will bring quality indicators for on-farm production. The results obtained with the application of this microorganism, from preliminary laboratory tests to field tests, with larger parcels, revealed that, in addition to improving the plant's nutritional status, there was also in improvement in health. The plants have become healthier, from the root system to the shoot system. Rice plants treated with Serratia presented up to 60% fewer diseases, such as brown spot, sheath blight and rice blast, the most harmful disease to rice' she reports. Fungi and bacteria combination In addition to the combined use of Serratia and NPK fertilizers, this bacterium has also been studied in this research in a mix with a fungus that is widely applied in agriculture, the Trichoderma. In field experiments at Embrapa, an aqueous solution with Serratia and Trichoderma was sprayed into the furrow during the bean sowing process. The use of these microorganisms has generated a 17% increase in grain productivity, in contrast to the treatment without the application of the mix. The hypothesis highlighted is that this result may have occurred because of these microorganisms' capacity of providing increases in plant development through nutrient absorption, growth hormones production and stimulation to higher efficiency of photosynthesis mechanisms. According to Nascente, other similar studies that combine, in pairs, different bacteria of types Bacillus, Burkholderia, Serratia and Azospirillum, as well as the fungus Trichoderma (see here), move in the same direction and allow us to affirm that these microorganisms are a good strategy to increase bean yield. Quality control required The study with microorganisms in association with plants can generate ready-made commercial products that can be purchased and applied to the crops, or the biological agents can be acquired so that the bioinput production process can be done on farm. In both cases, it is a practice that requires observation of quality criteria. According to Marcio Vinicius Côrtes, analyst in microbiology and bioinputs at Embrapa, quality control is an important activity. "This is one of the essential steps in bioinput production, regardless of the production model used. The bioproduct's quality is linked to its efficiency in the field. The concern with the adequate concentration of microbial cells and the bioinput's purity, the absence of contaminating microorganisms are key factors for the product to achieve its expected effect" he points out. Therefore, the production of bioinputs requires investments in infrastructure and monitoring of professionals who are capable of ensuring the quality of manufacturing procedures. The expert stresses that all stages of the bioinput production process contain critical points, from the reception of raw material to the final product supply, whether it is formulated and packaged or not. He also points out that the use of an authentic and recognized efficient strain is one more minimum condition for the success of this practice. "In addition to investment in equipment and adaptation of the production plant's building structure, it is necessary that the team involved in the process develops protocols, makes records and carries out constant monitoring of the various related steps, taking preventive and corrective action when needed, within the context of Good Manufacturing Practices", Cortez recommends. According to him, failure to observe quality procedures can generate damage to productivity, to rural workers and to consumers. Microorganism production in liquid culture media in inappropriate containers such as water tanks, which do not allow minimal control of the fermentation process, is a classic negative example. "Inadequate bioinput production will result in low-quality product, which, in turn, will not have the expected effect on management, and may bring this excellent technology into disrepute. It is worth noting as well that a poorly conducted process can result in the multiplication of microorganisms pathogenic to humans, that is, it can cause diseases. However, once again, it is important to emphasize that a bioproduct resulting from a well-conducted production process will be safe not only for farmers, but also for the final consumer", he concludes.