Tobacco/smoking culture runs in the family Solanaceae, is an agricultural product processed from the leaves of plants of the genus Nicotiana, whose commercial representative is the species Nicotiana tabacum L. Originating from South America, mainly from Mexico and the Bolivian Andes, from which the substance called Nicotine is extracted (JOSEPH, et al., 2015). Among the main cultivars are Virginia and Burley.

            Brazil is the second largest producer of leaf tobacco, behind only China, but maintains its position as the largest exporter of this product in the world market (SOARES et al., 2023). In 2021, approximately 86% of production was exported to the European Union, Asia, and the United States, making tobacco one of the most relevant agricultural products for the country's trade balance. Data from the same year revealed that Brazilian exports were 464,430 tons, generating revenue in the order of R$$ 7.93 billion (AFUBRA, 2022). Tobacco production in the southern region of the country, states of Rio Grande do Sul, Santa Catarina, and Paraná, occupied an area of 247 thousand hectares, with 560 thousand tons and generating income of R$$ 9.53 billion, for 128,448 families (AFUBRA, 2022).

            The greatest incentives for farmers in tobacco farming are the price stability proposed by the companies that purchase the production and the high added value of the product (SOARES et al., 2023). Thus, all Brazilian tobacco production is carried out in the system integrated with the industry, in which the tobacco companies are responsible for supplying the inputs used in the entire production process, from financing, technical assistance to the producer and guarantee of purchase of the product (SOUZA CRUZ, 2016). Compared to other crops, tobacco stands out for its profitability in small areas, the producer is integrated with the industry, which offers guaranteed purchase of the contracted production, there is also credit from banks, insurance from the crop to the arrival of the product at the company, with these factors in hand the producer feels safer and can work in small areas (NUNES, 2012).

            Tobacco cultivation does not only produce raw material for the cigarette industry. Through genetic improvement, plants such as Nicotiana benthamiana and Nicotiana tobaccum are being used as raw material for the manufacture of products that meet a wide variety of protein-based therapies for the treatment of Ebola, cancer and HIV/AIDS (ZAMPIERI, 2015, cited by SOARES 2023).

            In the South region, the number of farmers who depend on tobacco has been decreasing. In the 2020/2021 harvest compared to the 2021/2022 harvest, there was a reduction of 6.67%, 9,170 producing families left the activity, 26,766 hectares were uncultivated, a difference of 67,308 tons of tobacco that were no longer produced. This is worrying, since the Brazilian tobacco sector is largely focused on the international market, contributing to the surplus in the Brazilian trade balance and, socially, it is responsible for two million direct jobs, revealing its importance as the main agricultural product that generates income for small properties and producing municipalities, surpassing crops such as wheat, grapes and cocoa (AFUBRA, 2022).

            As tobacco production in Brazil is based on small properties, with an average size of 14.6 hectares, of which 17% are destined for planting. Around 53.2% represents the family income of farmers. In addition to tobacco cultivation, these families also produce food for their own consumption, with 33% for subsistence, 25% for animal breeding, 15% for native forests and 10% for reforestation (SINDITABACO, 2019).

Nutritional requirements

            Tobacco is a crop that is demanding in terms of N and K, making balanced fertilization necessary to replenish these nutrients in the soil in order to maximize productivity and ensure production quality (JESUS, 2016). Topdressing fertilization depends on the type of soil, plant, type of fertilizer, expected productivity and quality. To this end, the average recommendation of tobacco agroindustries is used, which according to Kaiser (2006) is 400 kg/ha.^-¹ and according to Oliveira and Costa (2012) the recommendation is 500 to 600 kg/ha^-¹.

            According to the liming and fertilization manual for the states of Santa Catarina and Rio Grande do Sul (2016), for tobacco cultivation (table 1), prepared by technicians linked to companies integrating the tobacco sector, the recommendations for the crop refer to a population of 15,000 to 17,000 plants/ha for Virginia tobacco and 18,000 to 20,000 plants/ha for Burley tobacco.

Table 1- Nitrogen requirement for tobacco cultivation.

Source: CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016.

            Apply between 60 and 80 kg of N/ha in the planting fertilization, pre-transplanting, and the remainder as top dressing. The amounts of N to be applied as top dressing, in installments, vary according to the type of tobacco, the organic matter content and soil texture, the climatic conditions and the variables related to the quality and style of tobacco to be produced. For Virginia tobacco, it is recommended that at least 50% of the nitrogen fertilization come from nitric fertilizers (CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016).

            It is recommended to use cover crops or green manure in the period between two crops, aiming at soil conservation and improvement of its chemical, physical and biological characteristics. In the case of using legumes, applications of N as top dressing can be reduced, according to the development of the crop (CQFS-COMMISSION ON CHEMISTRY AND SOIL FERTILITY, 2016).

            Phosphate fertilization should be applied entirely at planting (table 2). For potassium fertilization, apply 60 and 80 kg of K₂O/ha at planting, pre-transplanting, and the remainder as top dressing. When choosing fertilizer sources, the amount of chlorine applied should be limited to a maximum of 50 kg of Cl/ha (used only in fertilization at planting) (CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016).

Table 2- Phosphorus and potassium requirements in tobacco cultivation.

Source: CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016.

            In soil conservation systems, with direct planting in straw, P doses can be reduced.₂THE₅ and K₂The applied. In this case, follow the guidance of technical assistance (CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016).

Knowledge of the absorption rate, nutrient accumulation rate, and dry matter allows defining the requirement of the elements required at each phenological stage of the crop (CREMONESI et al., 2019). With this, it is possible to estimate the export by harvest and how much is necessary to return to the soil (ECHER et al. 2009, KURTZ et al. 2016), which is essential for fertilization management. Research on the nutrient absorption rate by crops can help in planning fertilization to optimize nutritional efficiency and increase production, since expressed in the form of response curves as a function of plant age, it informs times when they absorb nutrients in greater quantities, thus increasing knowledge of times when the addition of nutrients to plants is necessary (DIÓGENES, 2016).

            Micronutrients are so called due to the low amount absorbed in relation to macronutrients (KIRKBY 2012), but their deficiency affects plant growth and productivity. The functions of micronutrients are related to enzymatic activity, catalysis of reactions, and other physiological and biochemical processes (DINIZ et al. 1999). In an experiment carried out by Cremonesi et al. (2019) with seedlings of the hybrid Virgínia 405, the dry matter mass, content and daily accumulation rates of micronutrients and Al in the stem and leaves of the plant were evaluated. It was found that the maximum accumulation of dry matter was close to 68 days after transplanting (DAT), obtaining approximately 3.2 t ha^-1 of dry matter at the end of the cycle, with 61.3% represented by the leaves; and the peak accumulation for most micronutrients occurred after 105 DAT. The order of micronutrient accumulation for tobacco was Fe>Mn>B>Zn>Cu with 98.2, 85.3, 79.2, 59.6 and 62.5%, respectively, in addition to the maximum values obtained at 105, 135, 135, 135 and 110 DAT, respectively, where more than 60% of the absorbed micronutrients were deposited in the leaves. Al accumulation was 36 kg ha^-1, with 98.2% deposited in the leaves.

Soil management and conservation

            Conservation management practices aim to reduce the risk of soil erosion. In well-structured, decompacted soils, with corrected acidity and fertilizers and with a lot of straw, it is recommended to use minimum cultivation or direct planting systems. The use of crop rotation, avoiding other species of the family Solanaceae, is recommended for phytosanitary control and nutrient cycling (CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION, 2016).

Factors to consider:

            Tobacco is a crop that is demanding in terms of N and K, making balanced fertilization necessary to replenish these elements in the soil in order to maximize productivity and ensure production quality in order to meet consumer needs (JESUS, 2016). Quality is understood as the adequate balance of nicotine and sugar to obtain a pleasant flavor. These adequate characteristics are present in leaves that are gradually harvested from the plant as they mature, presenting an intense orange color after the curing process (YANG et al., 2015).

            For Jesus (2016), topdressing fertilization management is complex, and N has a very peculiar dynamic due to the diversity of chemical forms, reactions, and processes in which it is involved. N in the soil is subject to several losses, mainly through nitrate leaching and ammonia volatilization, both from mineral fertilizers and organic waste. The management to be adopted in fertilization is essential to mitigate these losses, whose dynamics are directly related to the efficiency of the use of N applied via fertilizers. Likewise, K also has its peculiarities in the soil, and its loss occurs fundamentally through leaching. To increase the use of nitrogen and potassium fertilizers, new technologies have been sought, such as the use of slow or controlled release fertilizers. With this, the aim is to minimize losses through leaching and, in the case of N, also through volatilization.

            With soil cultivation for several years, OM losses may occur, which affects the N content. Another reason for the reduction of OM is related to burning and soil disturbance, through plowing and harrowing, which favor its oxidation. OM reductions are faster at the beginning of crops, until a new equilibrium content is reached, which can take decades to happen (JESUS, 2016).

            A source of N and K is potassium nitrate (KNO₃), known as NOP, is commonly produced by the reaction of KCl with a nitrate source. Nitrate can come from sodium nitrate, nitric acid or ammonium nitrate (RODRIGUES et al, 2014). Chilean saltpeter is of great commercial importance, being a natural product extracted in the Atacama Desert, in Chile. It is a fertilizer of high solubility and purity, providing potassium and sodium nitrate, with some micronutrients. However, the use of this salt can increase the osmotic pressure of the solution, causing the absorption of water by plants to be reduced.

Mineral fertilization provides immediate crop productivity, however, successive fertilizer applications are necessary for management, due to the rapid depletion of nutrients available to plants. These fertilizers cause excessive costs, soil wear and tear, and limitations on crop production potential (RABELO, 2015). In addition, over time, depending on the dose applied, they can cause soil acidification, especially in the case of nitrogen (FRANCIOLI et al., 2016; REZENDE, 2022). In recent years, the use of fertilizers with slow or controlled release technology has increased significantly, such as organominerals and polymerized ones, which are highly efficient compared to conventional fertilizers (SILVA, 2017).

Types of soil management in tobacco cultivation

            There are three types of soil management used in tobacco planting: conventional, minimum tillage and direct planting (PRADELLA, 2018). “Soil preparation is one of the agricultural operations in which the aim is to alter its physical, chemical and biological state, in order to provide better conditions for the maximum development of cultivated plants”. Inadequate management can cause soil degradation, erosion and loss of nutrients (DERPSCH, 1985 apud GABRIEL FILHO et al., 2000, p. 954).

            Conventional soil management is the turning of the soil in its superficial layers with the objective of incorporating limestone and fertilizer, in addition, it aims to increase porosity, permeability and facilitate the absorption of water and air and, with this, the good development of plants (PRADELLA, 2018). It also incorporates green cover, whether it is weeds or green manure. The conventional process is carried out by plowing and harrowing the soil (GABRIEL FILHO et al., 2000, p. 954). This system requires attention to the topography of the terrain, “On terrains with a slope of up to 5%, wide-based terraces should be built. On slopes from 5% to 12%, the construction of narrow-based terraces is recommended. […].” (BARBOSA et al., 2009, p. 2).

            Minimum cultivation involves minimal manipulation and soil disturbance in preparation for planting a crop. It is recommended where the soil is not so compacted (PRADELLA, 2018). Subsoiling is carried out to decompact the soil in the planting line, and is mainly indicated for crops with slopes to prevent further erosion (ROSSETTO; SANTIAGO, 2018). According to the authors, minimum cultivation has advantages over traditional cultivation, mainly in reducing erosion and reducing soil preparation costs. For Barbosa et al. (2009, p. 2) from Embrapa, minimum cultivation is an intermediate soil management system “with little soil movement.”

            Direct planting is a soil preparation system with minimal human interference in the planting environment, only in the planting furrow, however it requires the desiccation of existing plants in the crop (PRADELLA, 2018). According to Barbosa et al. (2009, p. 2) direct planting “makes it possible to combine less soil mobilization and preservation of organic matter, thus being of fundamental importance not only for the sustainability of the environment, […]” as well as “direct and indirect influence on the chemical, physical-chemical and biological processes of the soil.

Ground cover

            THE cover crop cultivation, Pauletti et al. (2009) presents the ability to promote the absorption of nutrients in deep soil layers and accumulate them in the aerial part, providing benefits for the successor crop after the degradation of straw on the soil surface, in addition to demonstrating importance in management for weed control (SODRÉ FILHO et al., 2008). Furthermore, as we saw previously, the use of legumes as cover crops preceding tobacco crops can reduce the amount of N applied as cover crops.

Therefore, the use of conservationist practices, the choice of fertilizers that can collaborate with soil processes, preventing its depletion, in addition to all the technology used in production management, making the producer use adequate equipment to reduce direct contact with tobacco and the correct use of fertilizers and pesticides must be correctly used so that the producer's profitability, the continuous cycling of the soil act in a way that makes the entire tobacco production chain viable.

ILSA positioning for tobacco

ILSA is a world reference in the search for and transformation of renewable raw materials into high-performance products for modern agriculture. We work with organic and organomineral fertilizers for soil and leaf application, produced from collagen. Our organic matrices AZOGEL^® and GELAMIN^® are obtained through innovative and sustainable processes that guarantee the production of fertilizers with high nutritional value and high homogeneity (without variations in raw materials and guarantees.

Figure 1. ILSA fertilization suggestion according to tobacco phenological phases.

Image Source: SQM – Solutions for human progress

ILSA has a complete line of fertilizers in its portfolio capable of meeting the nutritional requirements of tobacco crops (Figure 1). When transplanting seedlings, the recommendation is to use the GRADUAL MIX line of organomineral fertilizers for soil application.^®.GRADUAL MIX^® provides macronutrients (NPK) more efficiently due to the presence of the organic matrix AZOGEL^®, which has organic carbon and nitrogen in its composition that favor, respectively, the biological activity of the soil and balanced vegetative development, due to the gradual supply of nitrogen, throughout the production cycle.

As discussed in the text, tobacco cultivation is highly demanding in N and K, requiring the application of these two nutrients as top dressing. For this moment, the fertilizer FERTI COMPLEX^® application via soil is the most indicated. FERTI COMPLEX^® is obtained from the combination in a single pellet of the AZOGEL matrix^® with mineral sources of N and K, which allows greater use of mineral nutrients and lower losses through volatilization and leaching processes.

ILSA's fertilizers for soil management are characterized by the gradual release of nitrogen and are rich in organic carbon, which enhances the activity of microorganisms in the soil, which will interfere with the mineralization of nutrients; increase in organic matter in the soil; greater absorption of potassium and other cations due to the increase in CEC; thus contributing to soil management and conservation.

For foliar fertilization management, the recommended fertilizers are ETIXAMIN MEGA^® and ILSAMIN AGILE^®. ETIXAMIN MEGA is obtained by combining the organic matrix GELAMIN^® rich in amino acids, with mineral sources of macro and micronutrients. MEGA allows the nutritional balance of plants, preventing possible deficiencies. ILSAMIN ÁGILE^® provides rapidly absorbed amino acids that interfere in various metabolic processes in plants, including overcoming climatic stresses.

Bibliographic references

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BARBOSA, FR et al. Integrated Production System of Common Beans in the Central Region of Brazil. EMBRAPA. Technical Circular 86. Santo Antônio de Goiás, GO December, 2009.

CQFS-SOIL CHEMISTRY AND FERTILITY COMMISSION. Liming and fertilization manual for the states of Rio Grande do Sul and Santa Catarina. Brazilian Society of Soil Science, 2016.

CREMONESI, Marcus Vinicius et al. Absorption rate, accumulation rate and export of micronutrients and aluminum by tobacco (Nicotiana tabacum L.). Journal of Agroveterinary Sciences, v. 18, n. 1, p. 13-23, 2019.

DINIZ, Josefa Diva Nogueira et al. Macronutrient absorption by banana explants in vitro. Brazilian Agricultural Research, v. 34, p. 1201-1209, 1999.

DIÓGENES, Talita Barbosa Abreu. Accumulation of dry matter and nutrients and response of caeté tomato to nitrogen and phosphorus doses. Federal Rural University of Semi-arid. Mossoró, RN. 2016.

ECHER, Fábio R.; DOMINATO, Júlio C.; CRESTE, José E. Nutrient absorption and distribution of fresh and dry mass among sweet potato organs. Brazilian Horticulture, v. 27, p. 176-182, 2009.

FRANCIOLI, Davide et al. Mineral vs. organic amendments: microbial community structure, activity and abundance of agriculturally relevant microbes are driven by long-term fertilization strategies. Frontiers in microbiology, vol. 7, p. 1446, 2016.

GABRIEL FILHO, Antonio et al. Conventional tillage and minimum soil cultivation in cassava crops under green manure conditions with vetch and black oats. Ciência Rural, Santa Maria, v.30, n.6, p.953-957, 2000.

JESUS, JULIANO DE. VIRGINIA, YIELD AND. QUALITY OF TOBACCO. 2016. Doctoral Thesis. Santa Catarina State University.

JOSEPH, Lunel et al. Alternatives for tobacco cultivation in the southern and extreme southern regions of Santa Catarina with the support of rural extension. Federal University of Santa Catarina. 2015.

KAISER, DR; Nitrate in soil solution and in drinking water sources in a tobacco-producing watershed. Dissertation, Universidade Federal de Santa Maria – UFSM, 2006.

KIRKBY, Ernest A. Introduction, definition, and classification of nutrients. In: Marschner's Mineral Nutrition of Plants. Academic press, 2023. p. 3-9.

KURTZ, Claudinei et al. Growth and nutrient absorption by the onion cultivar Bola Precoce. Horticultura Brasileira, v. 34, p. 279-288, 2016.

NUNES, R.; Tobacco as a source of income for farmers in the Southern region of Brazil: the dichotomy between income and health. Monograph, Universidade Federal de Santa Catarina – UFSC, 2012.

Oliveira, F.; COSTA, MCF; Tobacco cultivation (Nicotiana tabacum L.). Technical Dossier, University of São Paulo – USP, 2012.

PAULETTI, Volnei et al. Chemical attributes of a Latosol under no-tillage system as a function of fertilization strategy and soil sampling method. Brazilian Journal of Soil Science, v. 33, p. 581-590, 2009.

PRADELLA, Jeferson Luiz. Soil management related to tobacco production and its consequences. Federal University of Santa Maria – RS.2018.

RABELO, KCC Organomineral and mineral fertilizers: phytotechnical aspects in industrial tomato cultivation. 2015. 70 p. Dissertation (Master's in Agronomy) - Federal University of Goiás, Goiânia, 2015.

RATKE, RF Granulometric classes and application method of limestone in corn crops. 2011. Thesis (doctorate, Coordination of the Postgraduate Program in Agronomy, Federal University of Goiás). Goiania, GO, 2011.

REZENDE, Camila Isabel Pereira. Multispectral images to discriminate fertilizer sources in coffee plants. 2022.

RODRIGUES, MA de C. et al. Fertilization with coated KCl in corn crops in the Cerrado. Brazilian Journal of Agricultural and Environmental Engineering, p. 127-133, 2014.

ROSSETTO, R.; SANTIAGO, AD Minimum cultivation. AGEITEC. Embrapa Agency for Technological Information. Available at:

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SINDITABACO. Infographic. 2019. Available at: https://www.sinditabaco.com.br/site/wp-content/uploads/2017/04/Infografico-Pe.pdf

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Authors

• Agr Eng. Dr. Angélica Schmitz Heinzen
• Agricultural Eng. Msc. Carolina Custodio Pinto
• Agricultural Eng. Msc. Thiago Stella de Freitas