Embrapa Soja estimates that approximately 355.588 million tons of soybeans were harvested in the 2021/22 global harvest, with 123.829.5 million tons harvested on national soil, consolidating Brazil's leadership in grain production, followed by the United States and Argentina. In addition, according to data from the Brazilian Institute of Geography and Statistics (IBGE), among the main products originating from agriculture in 2021, soybeans had the highest production value, an estimated amount of R$341,747,600 thousand. Embrapa Soja explains that the history of soybean farming in Brazil began in the late 1960s, when two internal factors made the country begin to see soybeans as a commercial product, a fact that would later influence the global scenario of grain production. At the time, wheat was the main crop in southern Brazil and soybeans emerged as a summer option, succeeding wheat. Brazil was also beginning an effort to produce pigs and poultry, generating a strong demand for soybean meal. In 1966, commercial soybean production was already a strategic necessity, with around 500,000 tons being produced in the country.

            The explosion in the price of soybeans on the world market in the mid-1970s further awakened farmers and the Brazilian government itself. The country benefited from a competitive advantage over other producing countries: the Brazilian harvest was sold during the American off-season, when prices reached their highest levels. Since then, the country has invested in technology to adapt the crop to Brazilian conditions, such as improving soil and genetic conditions, a process led by the Brazilian Agricultural Research Corporation (Embrapa).

            Regarding nutrient absorption, soybeans have a very low initial rate due to their small growth at this stage. According to Carmello and Oliveira (2006), the stage of greatest nutritional demand begins around 30 days and remains high until the beginning of grain filling, when nitrogen fixation and photosynthetic activity are high and produce more accelerated development. These authors also mention that an intense translocation of nutrients, accumulated in the vegetative parts, occurs as grain filling progresses, reducing the demand for nutrients from the soil. Subsequently, physiological activities show a significant reduction, ending, with the maturation of the plant, absorption and the photosynthetic process.

            It is common knowledge that, after successive crops, nutrient stocks become compromised in the soil, requiring supplementation through fertilizing. According to Malavolta (1989), fertilization consists of adding nutrients to the soil that it can no longer provide to plants, filling the gap between the plant's requirements and the soil's reserves. Therefore, there are several factors to consider when choosing the ideal fertilizer for the crop. The crop's requirements, the environmental impact generated by the fertilizer, the form of absorption and its potential for increasing productivity are some of them. With this in mind, ILSA Brasil, in partnership with the Agroconect Institute of Agronomic Research, conducted an experiment with the objective of evaluating the use of the organomineral fertilizer Gradual MIX® 06 15 10 in increasing soybean productivity.

Material and methods

            The trial was carried out in the experimental field of the Agroconect LTDA Research Institute, under the supervision of Agr. Eng. Ma. Francine F. de M. Nava, in the municipality of Erechim, RS. The soybean cultivar used was BMX Zeus 55i57 RSF IPRO, with sowing on 11/23/2021 and harvest on 04/25/2022, density of 13 seeds per meter and spacing between rows of 0.5 m. The soil in the region is classified as Humic Aluminoferric Red Latosol, and a base fertilization was carried out together with potassium chloride (KCl). The treatments are described in Table 1, with four replicates each treatment. The fertilizer used for the ILSA Brasil® Treatment was Gradual MIX®, in the formulation 06 15 10, and the formulation 05 30 15 for the Standard Treatment.

Table 1. Treatments, doses and time of application.

            Regarding the climatic conditions during the trial period, the average temperature recorded was 21.18 ºC and the total rainfall was 742.2 mm. Phytosanitary management was carried out according to the needs and recommendations for soybean crops. The treatments were evaluated according to the yield components: productivity – in bags per hectare (sc ha^-1), and mass of a thousand grains (g) with grain moisture adjusted to 13 %, from the useful area of each experimental unit. The data obtained were submitted to the F test (p≤0.05).

Results and discussion

            Productivity data (sc ha^-1) and thousand grain mass (g) are described in Table 2. For the productivity variable, the treatment with ILSA Gradual Mix 06 15 10 obtained the result of 82 sc ha^-1, compared to the control, which obtained 79 sc ha^-1, generating an increase of three sc ha^-1, which confirms the very high level of ILSA Brasil® fertilizers. The organomineral fertilizer Gradual MIX®, like all ILSA Brasil® fertilizers, has a gradual release of nitrogen, which allows this nutrient to remain assimilable for longer, providing balanced crop development. Freitas (2017) explains that this occurs because this type of fertilizer delays the initial availability of nutrients, or increases their availability, aiming to synchronize the release with the plant's demand for the nutrient, reducing product losses in the environment through leaching and potentially increasing the efficiency of nitrogen fertilization.

Table 2. Productivity (sc ha^-1) and mass of a thousand grains (g) of soybeans subjected to different base fertilizers.

            Another important factor to be considered is the cation exchange capacity (CEC), which directly influences crop productivity. CEC directly interferes with soil stability, pH, nutrient availability and fertilization effectiveness. Gradual MIX®, in the formulation used in this test, has a CEC of 80 %, also justifying the higher productivity in relation to the Standard treatment. Allowing the good development of soil microorganisms is an essential factor in a good fertilizer, as it also contributes to increased productivity, since these organisms are directly related to the cycling and subsequent availability of nutrients. The AZOGEL® matrix, used in the formulation of ILSA Brasil® solid fertilizers, has high biological affinity, once again justifying the higher value in productivity. This matrix is also characterized by the presence of several essential amino acids, which contribute significantly to productivity – according to Gazola et al. (2015), and can be used at times of greater plant demand.

            Regarding the thousand-grain mass parameter (Table 2), the Standard treatment obtained a better result, however this discreet difference did not interfere in the final productivity. This can be explained by the fact that the treatment with Gradual MIX® provided a greater number of grains per pod, which justifies its superior productivity and highlights its potential for use in soybean farming.

Conclusion

            Organomineral fertilizers are the bet for the future. This is because, according to Teixeira et al. (2014), the application of these inputs reduces the high costs of fertilization and allows the simultaneous supply of mineral nutrients and organic matter. In addition to this characteristic, Gradual MIX® gradually promotes the supply of nutrients associated with the supply of amino acids, making it a product that stands out from others available on the market. This occurs due to its organic matrix, AZOGEL®, which is an agricultural gelatin derived from animal collagen. It is essential to emphasize the importance of amino acids for agriculture. This is because, as Albuquerque and Dantas (2010) point out, amino acids are involved in a large part of the primary and secondary metabolism, leading to the synthesis of several compounds that influence productivity.

            Based on some evidence, it is believed that some amino acids can act as plant protectors against the action of mineral salts and other agrochemicals or, on the contrary, increase the absorption and effect of these products (Castro, 2006). Even though they are capable of synthesizing the 20 essential amino acids, exogenous supply in plants presents excellent results. Castro and Carvalho (2014) consider that amino acids can be classified in the group of anti-stress agents, compounds capable of acting on morphophysiological processes of the plant as precursors of an endogenous hormone or enzymes and the provision of compounds that form growth promoters. In this sense, even when experiencing stressful situations, the plant recovers quickly, mitigating any negative effects on productivity.

            Finally, it is essential to note that all fertilizers produced by ILSA Brasil® have a low environmental impact in all their production processes, contributing to a sustainable production system and supporting the environment, in addition to the increase generated in productivity. The fertilization process must be carried out rationally, which presupposes the adequate use of fertilizers, avoiding insufficient or excessive applications, in order to provide the plants with the nutrients that are actually needed, in the appropriate quantities and at the appropriate times, while simultaneously preserving the environment. To this end, it is necessary not only to know the state of soil fertility, but also to know whether the nutrients present there are being effectively used by the crop. Therefore, the doses to be used must be based on soil analysis and on the recommendation of an agricultural engineer.

Bibliographic references

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CARMELLO, QAC; OLIVEIRA, FA de. Soybean crop nutrition: current situation and perspectives. Visão Agrícola Magazine, Piracicaba, n. 5, p. 8-11, 2006.

CASTRO, PRC Hormonal control agrochemicals in tropical agriculture. Rural Producer Series, ESALQ, Piracicaba, n. 32, 2006. 46 p.

CASTRO, PCR; CARVALHO, MEA Amino acids and their applications in agriculture. Rural Producer Series, ESALQ, Piracicaba, n. 57, 2014. 60 p.

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FREITAS, T. Conventional, stabilized, slow-release or controlled-release nitrogen fertilizers in coffee crops: efficiency and costs. UFLA, Lavras, 2017. 97 p. (Master's Dissertation)

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Brazilian Institute of Geography and Statistics (IBGE) – Agricultural Production. Available at: https://www.ibge.gov.br/explica/producao-agropecuaria/

MALAVOLTA, E. ABC of fertilization. 5th ed. São Paulo: Ceres, 1989, 294 p.

TEIXEIRA, WG; SOUSA, RTX; KORNDÖRFER, GH Response of sugarcane to phosphorus doses supplied by organomineral fertilizer. Bioscience Journal, Uberlândia, v. 30, n. 6, p. 1729-1736, 2014.

Authors

• Agricultural Eng. Msc. Aline Tramontini dos Santos
• Agricultural Eng. Msc. Carolina Custodio Pinto
• Agricultural Eng. Msc. Thiago Stella de Freitas