Alterações nos atributos químicos de um latossolo em resposta a reaplicação de calcário e escória de siderurgia em sistema de plantio direto
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Data
2021-07-28
Autores
Silva, Alessandra Vieira da
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Universidade Estadual Paulista (Unesp)
Resumo
A maioria dos solos do Brasil são classificados como ácidos, que limita muito a produção agrícola no país. Com isso é necessário a prática de calagem utilizando o calcário para que ocorra a correção da acidez do solo e a disponibilização dos nutrientes para as plantas. Todavia, existem outros corretivos que podem ser utilizados, tais como as escórias de siderurgia cujas informações sobre seu uso no solo ao longo do tempo e alterações fisiológicas e bioquímicas proporcionadas em plantas ainda carecem de informações. Visando contribuir para este tema, realizou-se experimento em condições de campo na Faculdade de Ciências Agronômicas / UNESP. O experimento foi instalado em blocos casualizados com subparcelas subdivididas medindo 42 m2 e quatro repetições. Os tratamentos foram constituídos por dois fatores: corretivos e formas de aplicação. Os corretivos foram: escória de aço inox, escória de aciaria, escória forno de panela, wollastonita, calcário agrícola, calcário agrícola calcinado e tratamento testemunha, sem a aplicação de corretivo. As formas de aplicação dos corretivos foram superficiais e incorporadas, sendo que em ambas as formas os materiais foram aplicados de forma manual e somente na forma incorporada o material foi revolvido usando grade niveladora na camada subsuperficial (20 cm). Nesse sentido, o capítulo 1 propôs avaliar as alterações fisiológicas e bioquímicas em plantas de soja em estádio vegetativo submetidas à aplicação de calcário e escórias de siderurgia em sistema de plantio direto. Decorridos 30 dias após a aplicação dos materiais no solo, foi implantada a cultura da soja, e posteriormente avaliados os seguintes índices: índice de área foliar, teor relativo de água, perdas eletrolíticas, teor de pigmento e massa fresca e seca de as folhas e o caule na fase R1. Ao final do ciclo da cultura, também foram avaliados os componentes de produção e produtividade de grãos da cultura da soja. A aplicação incorporada resultou em maior biomassa foliar, caule, número de plantas por metro linear, teores foliares de macronutrientes e micronutrientes, teor de proteína solúvel total, teor de silício foliar, atividades das enzimas superóxido dismutase, peroxidase e catalase, e o número de vagens por planta. A forma de aplicação dos corretivos de acidez alterou a resposta da soja, a incorporação de corretivos proporcionou maior produção de massa foliar fresca e seca e massa fresca do caule, aumentou o teor de clorofila b, teor de K nas folhas e contribuiu para um maior número de plantas por hectare e número de vagens por planta em relação à aplicação na superfície, apesar dos benefícios, não houve efeito do modo de aplicação sobre a produtividade da soja, mostrando que tanto a incorporação quanto a aplicação na superfície são eficientes no aumento da produtividade de grãos da soja. O objetivo do capítulo 2 foi avaliar o efeito da aplicação das escórias de siderurgia nos atributos químicos do solo e nas respostas metabólicas e produtividade de grãos na cultura do feijoeiro em sistema de plantio direto (SPD). Passados 16 meses que os materiais foram aplicados no solo foi implantada a cultura do feijoeiro avaliando-se, 40 dias após a germinação, altura de planta, massa seca de folhas e caules, o conteúdo relativo de água (CRA), perdas de eletrólitos (PE) e teor de pigmentos (Clo a, Clo b e carateoides), teor foliar de macronutrientes e micronutrientes, teor de proteína solúvel total, teor de silício na folha, atividade da enzima superóxido dismutase - SOD, peroxidase e catalase. Realizou-se também análise de trocas gasosas, fotossíntese, concentração interna de CO2, condutância estomática ao vapor de água, e taxa transpiratória. Ao final do ciclo da cultura avaliou-se componentes da produção e produtividade de grãos. Os valores de P, pH, V% e Si aumentaram com a aplicação dos silicatos, refletindo no número de plantas por metro e na massa de 100 grãos, contudo não mostraram interferência na produção de grãos do feijoeiro. O modo de aplicação superficial dos corretivos de acidez aumentou a fotossíntese e a condutância estomática das plantas de feijoeiro. As plantas de feijoeiro apresentaram elevados teores de Fe e Mn, resultando em a ativação das três enzimas SOD, POD e CAT, que atuam como indicador de estresse. Os silicatos apresentaram melhores resultados quando comparados aos calcários, no sistema de plantio direto
Most soils in Brazil are classified as acidic, which greatly limits agricultural production in the country. Thus, it is necessary to practice liming using limestone so that soil acidity is corrected and nutrients are made available to the plants. However, there are other correctives that can be used, such as steel slag providing information about its use in the soil over time and physiological and biochemical changes provided in plants still lack information. Aiming to contribute to this theme, an experiment was carried out under field conditions at the Faculty of Agricultural Sciences / UNESP. The experiment was installed in randomized blocks with subdivided subplots measuring 42 m2 and four replications. The treatments consisted of two factors: correctives and forms of application. The correctives were: stainless steel slag, steel slag, ladle slag, wollastonite, agricultural limestone, calcined agricultural limestone and control treatment, without the application of corrective agent. The forms of application of correctives were superficial and incorporated, being that in both forms of materials they were manually and only in the incorporated form the material was revolved using a leveling grade in the subsurface layer (20 cm). In this sense, chapter 1 proposed to evaluate the physiological and biochemical changes in soybean plants in the vegetative stage submitted to the application of limestone and steel slag in a no-tillage system. Twenty days after the application of the materials to the soil, the soybean crop was implemented, and the following indexes were subsequently adopted: leaf area index, relative water content, electrolyte losses, pigment content and fresh and dry mass of leaves and leaves. stem at stage R1. At the end of the crop cycle, the components of production and grain yield of the bean crop were also obtained. An incorporated application resulted in higher leaf biomass, stem, number of plants per linear meter, leaf contents of macronutrients and micronutrients, total soluble protein content, leaf silicon content, activities of superoxide dismutase, peroxidase and catalase enzymes, and the number of pods per plant. The way of applying the acidity correctives changed the soybean response, we observed that the incorporation of correctives provided greater production of fresh and dry leaf mass and fresh stem mass, also increased the chlorophyll b content, K content in the leaves and contributed for a greater number of plants per hectare and number of pods per plant in relation to surface application, despite the benefits, there was no effect of the mode of application on soybean yield, showing that both incorporation and surface application are efficient in increasing soybean grain yield. In this sense, the objective of chapter 2 was to evaluate the effect of the application of steelmaking slag on the chemical attributes of the soil and on the metabolic responses and grain yield in the bean crop under no-tillage system (SPD). After 16 months that the materials were obtained in the soil, the bean crop was implanted, evaluating, 40 days after germination, plant height, fresh and dry mass of leaves and stems, the relative water content (CRA), electrolyte losses (PE) and pigment content (Clo a, Clo b and carateoids), leaf macronutrient and micronutrient content, total soluble protein content, leaf silicon content, superoxide dismutase - SOD, peroxidase and catalase enzyme activity. A gas exchange analysis was also carried out for what was needed a plant for treatment; also evaluated photosynthesis, internal CO2 concentration, stomatal conductance to water vapor, and transpiration rate. At the end of the crop cycle, components of production and grain yield were evaluated. The values of P, pH, V% and Si increased with the application of silicates, reflecting in the number of plants per meter and in the mass of 100 grains, however there was no differentiation in the bean grain production. The surface application of acidity correctives increased photosynthesis and stomatal conductance of common bean plants. The bean plants independent of Fe and Mn, discover in activation of the three enzymes SOD, POD and CAT, which act asstress indicator. Silicates had better results when compared to limestones, in the no-tillage system.
Most soils in Brazil are classified as acidic, which greatly limits agricultural production in the country. Thus, it is necessary to practice liming using limestone so that soil acidity is corrected and nutrients are made available to the plants. However, there are other correctives that can be used, such as steel slag providing information about its use in the soil over time and physiological and biochemical changes provided in plants still lack information. Aiming to contribute to this theme, an experiment was carried out under field conditions at the Faculty of Agricultural Sciences / UNESP. The experiment was installed in randomized blocks with subdivided subplots measuring 42 m2 and four replications. The treatments consisted of two factors: correctives and forms of application. The correctives were: stainless steel slag, steel slag, ladle slag, wollastonite, agricultural limestone, calcined agricultural limestone and control treatment, without the application of corrective agent. The forms of application of correctives were superficial and incorporated, being that in both forms of materials they were manually and only in the incorporated form the material was revolved using a leveling grade in the subsurface layer (20 cm). In this sense, chapter 1 proposed to evaluate the physiological and biochemical changes in soybean plants in the vegetative stage submitted to the application of limestone and steel slag in a no-tillage system. Twenty days after the application of the materials to the soil, the soybean crop was implemented, and the following indexes were subsequently adopted: leaf area index, relative water content, electrolyte losses, pigment content and fresh and dry mass of leaves and leaves. stem at stage R1. At the end of the crop cycle, the components of production and grain yield of the bean crop were also obtained. An incorporated application resulted in higher leaf biomass, stem, number of plants per linear meter, leaf contents of macronutrients and micronutrients, total soluble protein content, leaf silicon content, activities of superoxide dismutase, peroxidase and catalase enzymes, and the number of pods per plant. The way of applying the acidity correctives changed the soybean response, we observed that the incorporation of correctives provided greater production of fresh and dry leaf mass and fresh stem mass, also increased the chlorophyll b content, K content in the leaves and contributed for a greater number of plants per hectare and number of pods per plant in relation to surface application, despite the benefits, there was no effect of the mode of application on soybean yield, showing that both incorporation and surface application are efficient in increasing soybean grain yield. In this sense, the objective of chapter 2 was to evaluate the effect of the application of steelmaking slag on the chemical attributes of the soil and on the metabolic responses and grain yield in the bean crop under no-tillage system (SPD). After 16 months that the materials were obtained in the soil, the bean crop was implanted, evaluating, 40 days after germination, plant height, fresh and dry mass of leaves and stems, the relative water content (CRA), electrolyte losses (PE) and pigment content (Clo a, Clo b and carateoids), leaf macronutrient and micronutrient content, total soluble protein content, leaf silicon content, superoxide dismutase - SOD, peroxidase and catalase enzyme activity. A gas exchange analysis was also carried out for what was needed a plant for treatment; also evaluated photosynthesis, internal CO2 concentration, stomatal conductance to water vapor, and transpiration rate. At the end of the crop cycle, components of production and grain yield were evaluated. The values of P, pH, V% and Si increased with the application of silicates, reflecting in the number of plants per meter and in the mass of 100 grains, however there was no differentiation in the bean grain production. The surface application of acidity correctives increased photosynthesis and stomatal conductance of common bean plants. The bean plants independent of Fe and Mn, discover in activation of the three enzymes SOD, POD and CAT, which act asstress indicator. Silicates had better results when compared to limestones, in the no-tillage system.
Descrição
Palavras-chave
Glycine max (L.), Acidez do solo, Silicatos, Calcário, Silicate, Carbonate