Vegetable Fertilization Management
Brazilian vegetable production is highly diversified and segmented, with the production volume concentrated in six species – potatoes, tomatoes, watermelons, lettuce, onions and carrots, as mentioned on the Embrapa website. There are several markets within the marketing of vegetables, from the so-called organic to small family producers. Regardless of the form of production, whether on small or large properties, vegetable cultivation generates a good share of the market and, consequently, generates a series of jobs. Because it is a group with very varied species, it is necessary to be aware of the different nutritional requirements and preferences for type of management and soil. The response of vegetable plants to fertilization is influenced by a series of factors: cultivated species, climate, soil type, source of nutrients used in fertilization, among others, as mentioned by Andrade et al., 2012. However, one element that cannot be neglected, regardless of the crop, is nitrogen, which is highly required by most species.
Importance of adequate nutrient supply for vegetable cultivation – Nitrogen, potassium, match and sulfur
Nitrogen (N) is the most important macronutrient for plants. What distinguishes it from other elements is that it can be absorbed both in the form of cation (NH4+) as anion (NO3–). According to Bredemeier & Mundstock (2000), in many production systems, nitrogen availability is almost always a limiting factor, influencing plant growth more than any other nutrient. N has the basic function of plant growth, is responsible for their dark green color and, as it promotes the development of the root system, improves the absorption of other nutrients from the soil. As it is an essential component of all proteins, participating in all plant tissues, N is characterized as indispensable in each and every phase of the plant, whether vegetative or reproductive.
Potassium (K), in turn, is an important macronutrient that is associated with the translocation of sugars and organic acids in the plant, which makes it essential for the quality of fruits and grains. Furthermore, according to the International Potash Institute (IPI) (2013), K has two other essential functions for plants: enzyme activation, which is essential for metabolic processes, especially the production of proteins and sugars; and it is also responsible for maintaining water content and, therefore, cell turgor – a biophysical role. Turgid cells maintain leaf vigor so that photosynthesis can proceed efficiently. The relationship between water and cellular nutrient content controls the movement of both in the plant, as well as the transport of sugars produced by photosynthesis to storage organs, such as grains, tubers, beet roots and fruits, as already mentioned.
Phosphorus (P), as explained by Grant et al. (2001), is crucial to plant metabolism, playing an important role in cell energy transfer, respiration and photosynthesis, in addition to being a structural component of the nucleic acids of genes and chromosomes, as well as of many coenzymes, phosphoproteins and phospholipids. According to these authors, limitations in the availability of P at the beginning of the vegetative cycle can result in developmental restrictions, from which the plant does not recover later, even when increasing the supply of P to adequate levels. An adequate supply of P is essential from the initial stages of plant growth. P is absorbed in the inorganic forms H2DUST4– and HPO42- and, to become available to plants, it must go through the action of soil microorganisms.
In addition to N, P and K, another essential macronutrient is sulfur (S), whose function is similar to that of nitrogen, however, it is present in smaller quantities in plants, ranging from 3 to 5 % of dry mass. S is absorbed mainly in the form of the sulfate anion (SO42-), and can also be absorbed by the leaves in the form of sulfur dioxide gas (SO2). In plants, S is mostly found in proteins (Rocha et al., 2015), actively participating in the synthesis of the amino acids cysteine, cystine and methionine. And, due to the presence of these amino acids, S acts indirectly in the plant's resistance mechanisms, both to biotic and abiotic stress. In addition, S is closely linked to nitrogen metabolism, converting it from non-protein N to protein N, and is also associated with the formation and development of nodules and in the process of atmospheric nitrogen fixation (N2). Plants of the Alliaceae family (Allioideae) are extremely demanding in S and, in the case of onions, it is the third or fourth in decreasing order of accumulation, being the element responsible for the pungency of these bulbs.
Fertilizing vegetables with ILSA Brasil
ILSA has been in the market for over 65 years and is a global reference in biotechnology for transforming raw materials from renewable sources into high-performance products for agriculture. We use modern and sustainable industrial methods, which are an excellent solution for environmental liabilities in various industrial sectors. The result of these processes is the production of highly efficient fertilizers, which help organic and specialized agriculture to increase the productivity and quality of crops, in an increasingly responsible and conscious manner. To obtain these fertilizers, ILSA Brasil relies on two matrices: AZOZEL® and GELAMIN®, which will be explained below.
AZOGEL® is the organic base from which all of ILSA's solid organic and organomineral products are derived, and is largely responsible for the proven agronomic quality of the products. Thanks to the industrial thermal hydrolysis process (FCH®), AZOGEL® is a unique and highly homogeneous product, with no variations in the raw material or guarantees, and a high CTC. It also has a high content of organic carbon and nitrogen, where the C/N ratio allows it to be a food source for microorganisms without causing N immobilization, since, despite being gradual, the release of N into the system occurs more quickly than with other sources of organic matter and/or organic N, making it a product with high biological affinity. Using this matrix, the Gradual MIX®, AZOSLOW®, N-Time+® and S-Time® fertilizers are produced, all recommended for growing vegetables, covering all stages of plant development.
The Gradual MIX® line of fertilizers, available in formulations for planting and topdressing fertilization, has as its main characteristic the gradual supply of N, allowing this nutrient to remain assimilable for longer, which allows for the balanced development of the plant, in addition to simultaneously providing calcium and magnesium. In addition, it reduces nutrient loss due to the protective action of high CTC organic matter. In addition to nutrients, Gradual MIX® also provides amino acids to plants, a differential in relation to similar fertilizers. Although plants are capable of synthesizing amino acids, exogenous supplementation in agricultural areas is considered a smart strategy. According to Castro and Carvalho (2014), amino acids can be classified in the group of antistress 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, promoting resistance to biotic and/or abiotic stresses.
AZOSLOW® is a pelletized organomineral fertilizer characterized by containing N from AZOGEL® in association with soluble N from urea, available in two formulations: AZOSLOW® 22 (22 % of N) and AZOSLOW® 29 (29 % of N). These fertilizers are characterized by the gradual release of nitrogen – promoting uniform distribution and making N assimilable for longer, reducing losses due to leaching. These products can be used as top dressing and have, as their main advantage, greater use of N compared to the use of urea – which presents losses due to volatilization. It also contains organic C in its composition (25 %), a component element of several organic compounds, such as carbohydrates, lipids, genetic material, proteins, among others. OC is also one of the main compounds present in soil organic matter (SOM), and its quantity will depend mainly on the action of decomposing microorganisms present in the soil biota. For this reason, the use of AZOSLOW® promotes the biological activity of the soil, which is so important for agriculture in general.
In vegetable cultivation, the use of animal manure is very common. However, this practice can pose some risks to the health of the garden, since this material can be contaminated with potential pathogens, pests and unwanted seeds. As a replacement for animal manure, ILSA Brasil offers the N-Time+® fertilizer, which can be applied together with planting fertilization (Gradual MIX® line), being incorporated into the soil. This fertilizer is highly efficient and provides N throughout the production cycle, due to the continuous release of this element. As it is a highly homogeneous product, it is easy to apply, especially when compared to manure, in addition to reducing application costs. N-Time+®, in addition to all its other advantages, also promotes increased biological activity in the soil, as it has a high affinity with microorganisms essential to plants.
S-Time® is also a highly efficient pelletized organomineral fertilizer, which contains organic C, organic N and elemental S, in addition to presenting a low C/N ratio and high CEC, simultaneously providing amino acids from the AZOGEL® matrix. This fertilizer can be used together with planting fertilization in areas where there is a S deficit, replacing N-Time+®. Due to its chemical form, S tends to descend in the soil profile, accumulating in the lower layers, which can generate a marked deficiency in the crop cycle. Due to the fact that it presents a gradual release of N and S, S-Time® allows these nutrients to be available throughout the entire production cycle, also targeting the succession of crops (winter/summer), providing greater productivity. Sulfur behaves very similarly to N in the soil – since it occurs in several forms. However, in order to be absorbed by plants, it needs to be transformed into sulfate through the action of soil microorganisms. Due to its high concentration of organic carbon, S-Time® contributes to and enhances the activity of these microorganisms, preventing losses due to leaching of these nutrients. As previously mentioned, S is directly associated with the synthesis of proteins and essential amino acids, which act as inducers of resistance to attacks by diseases and pests, in addition to having an insect-displacing effect, making plants more tolerant to stresses caused by biotic factors.
The GELAMIN® matrix is manufactured by ILSA Brasil and sold on all continents of the world, for use in a wide range of crops. It is an organic matrix produced from collagen, rich in organic carbon and nitrogen – where 56 % of this N is found in the protein form of amino acids. The product is obtained through an innovative and sustainable industrial process called Fully Controlled Enzymatic Hydrolysis (FCHE®). From this matrix, ILSA Brasil's liquid and water-soluble fertilizers are obtained, belonging to the ILSA TOP and ILSA TEC lines, which can be used both in foliar application and in fertigation. The high-efficiency fertilizers Etixamin KALLY® and Ilsamin CaMg® are derived from this matrix.
Etixamin KALLY® is an organomineral fertilizer – formulated in soluble powder, exclusive to ILSA Brasil, which provides organic carbon (10 %) and nitrogen (3.5 %), potassium (in the form of K2O – 37 %) and sulfur (12 %) in association with amino acids present in the organic matrix, for use via foliar application as a complement to soil fertilization. As previously discussed, the presence of K stimulates photosynthesis and other metabolic processes, such as the transport of sugars throughout the plant, which promotes and accelerates the balanced growth of crops. Furthermore, because it is directly associated with the water regulation of the plant, the presence of this nutrient in adequate quantities promotes resistance and/or tolerance to the most diverse types of stress – especially water stress, allowing the plant to remain balanced in times of drought, without compromising productivity. The absorption of this fertilizer, as it is via foliar application, occurs quickly, avoiding possible deficiencies, which enhances the filling of fruits, tubers and grains – since, as previously mentioned, K is directly related to the processes of sugar translocation in the plant.
ILSA Brasil also offers the fertilizer Ilsamin CaMg®, used for foliar application – generally at the end of the cycle, as a complement to soil fertilization. The use of this fertilizer prevents and/or solves problems of specific deficiencies of calcium (Ca) and magnesium (Mg), and is also recommended for the most critical phases. Ca is one of the components of the cell wall, actively acting in the structure of the plant and, for this reason, the adequate supply of this element, in addition to increasing resistance to stress, also tends to increase the shelf life of vegetables – especially leafy vegetables. Ca is also associated with the formation of the pollen tube and the germination of the pollen grain, processes that are essential for the formation of quality fruits. Mg, in turn, is an essential component of chlorophyll molecules, being directly associated with the photosynthetic process of the plant. In addition, magnesium also acts in protein synthesis and in the translocation of photoassimilates via the phloem, which generates an increase in the concentration of sugars in fruits, tubers and bulbs.
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. It is important to mention that the fertilization to be carried out must be rational, which presupposes the adequate use of fertilizers, avoiding insufficient or excessive applications, in order to provide the plants with the nutrients that are effectively needed, in the appropriate quantities and at the appropriate times, 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 are not described in the text because they should be based on soil analysis and on the recommendation of an agricultural engineer.
Bibliographic references
ANDRADE, EMG; SILVA, HS; SILVA, NS; SOUSA JR., JR; FURTADO, GV Organomineral fertilization in leafy vegetables, fruits and roots. Green Journal of Agroecology and Sustainable Development, v. 7, n. 3, 2012.
BREDEMEIER, C.; MUNDSTOCK, CM Regulation of nitrogen absorption and assimilation in plants. Rural Science, Santa Maria, v. 30, p. 365-372, 2000.
CASTRO, PRC; CARVALHO, MEA Amino acids and their applications in agriculture. Rural Producer Series, Piracicaba, n. 57, 2014. 58 p.
INTERNATIONAL POTASH INSTITUTE (IPI). Potassium, the Quality Element in Agricultural Production. 2013. 38 p.
ROCHA, JHT; GOLÇALVES, JLM; GODINHO, TO; SOUZA FILHO, LFS Nutrition and fertilization with sulfur and use of gypsum in eucalyptus plantations. IPEF Technical Circular, n. 208, p. 1-14, 2015.
Authors
- Agricultural Eng. Msc. Aline Tramontini dos Santos
- Agricultural Eng. Msc. Carolina Custodio Pinto
- Agricultural Eng. Msc. Thiago Stella de Freitas
