Suplementação foliar de cálcio e boro melhora a eficiência fotossintética e aumenta a produtividade da soja
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Data
2021-07-05
Autores
Galeriani, Tatiani Mayara
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O Brasil destaca-se por ser um dos maiores produtores de soja do mundo. Dentre as tecnologias adotadas para o aumento da produtividade, encontra-se a fertilização foliar. A adubação suplementar com cálcio (Ca) e boro (B) é uma prática que vem sendo utilizada no estádio de florescimento da soja com o propósito de aumentar o número de vagens por planta, decorrente da maior retenção de flores e da fixação das vagens, podendo consequentemente elevar a produtividade da cultura. Neste contexto, o objetivo deste trabalho foi avaliar os efeitos da suplementação foliar de Ca e B durante a floração no desempenho nutricional, metabólico e da produtividade da soja. O experimento foi conduzido na Fazenda Experimental Lageado pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista “Júlio de Mesquita Filho”, em Botucatu-SP nas safras de soja 2018/2019 e 2019/2020. O delineamento experimental utilizado foi o de blocos casualizados (DBC), os tratamentos consistiam da presença (+ Ca e B) e ausência de (- Ca e B). As doses utilizadas foram a de 400 g de Ca e 40 g de B ha-1, cujas as aplicações foram realizadas no estádio R1 da soja. Avaliaram-se o estado nutricional da cultura, parâmetros de trocas gasosas, enzima fotossintética (Rubisco), concentração de açúcar solúvel total, teor de proteína na folha, parâmetros agronômicos e produtividade de grãos. A suplementação de Ca e B proporcionaram aumento do teor de B foliar. A fotossíntese líquida, a condutância estomática, a eficiência do uso da água e a carboxilação aumentaram quando Ca e B foram aplicados. Consequentemente, a melhora da fotossíntese levou ao aumento da concentração de açúcar e proteína na folha. A melhora na atividade metabólica não afetou a massa de grãos por planta, mas aumentou o número de vagens por planta e a produtividade. A alteração na produtividade foi influenciada por uma cascata de eventos, a melhora na atividade fotossintética associada com o aumento da produção de açúcar pode ter aumentado o número de estruturas reprodutivas, culminando diretamente no aumento da produtividade de grãos da soja.
Brazil stands out for being one of the largest producers of soy in the world. Among the technologies used to increase yields is foliar fertilization. Supplemental fertilization with calcium (Ca) and boron (B) is a practice used in the flowering stage of soybean to increase the number of pods per plant, as the flowering is better maintained and the pods are corrected, which can lead to an increase in crop yield. The objective of this work was to evaluate the effects of foliar supplementation of Ca and B on nutritional, metabolic and yield components of soybean. The experiment was conducted in the Experimental Farm Lageado of the Faculty Agronomic Sciences of the State College of São Paulo "Júlio de Mesquita Filho", in Botucatu- SP in the 2018/2019 and 2019/2020 harvest seasons. The experimental design consisted of randomized blocks (DBC), treatments consisted of the presence (+Ca and B) and absence of (-Ca and B). The doses used were 400 g Ca and 40 g B ha-1, which were made as applications at stage R1 of soybean. Plant nutritional status, gas exchange parameters, photosynthetic enzyme (Rubisco), total soluble sugar concentration, leaf protein content, agronomic parameters and grain yield. Addition of Ca and B resulted in an increase in leaf B content. Net photosynthesis, stomatal conductance, water use efficiency and carboxylation increased when Ca and B were obtained. Consequently, the improvement of photosynthesis increased the concentration of sugar and protein in the leaf. Improvement in metabolic activity did not affect grain mass per plant, but increased the number of pods per plant and yield. The change in yield was influenced by a cascade of events. The improvement in photosynthetic activity combined with the increase in sugar production may have increased the number of reproductive structures, which directly led to an increase in soybean grain yield.
Brazil stands out for being one of the largest producers of soy in the world. Among the technologies used to increase yields is foliar fertilization. Supplemental fertilization with calcium (Ca) and boron (B) is a practice used in the flowering stage of soybean to increase the number of pods per plant, as the flowering is better maintained and the pods are corrected, which can lead to an increase in crop yield. The objective of this work was to evaluate the effects of foliar supplementation of Ca and B on nutritional, metabolic and yield components of soybean. The experiment was conducted in the Experimental Farm Lageado of the Faculty Agronomic Sciences of the State College of São Paulo "Júlio de Mesquita Filho", in Botucatu- SP in the 2018/2019 and 2019/2020 harvest seasons. The experimental design consisted of randomized blocks (DBC), treatments consisted of the presence (+Ca and B) and absence of (-Ca and B). The doses used were 400 g Ca and 40 g B ha-1, which were made as applications at stage R1 of soybean. Plant nutritional status, gas exchange parameters, photosynthetic enzyme (Rubisco), total soluble sugar concentration, leaf protein content, agronomic parameters and grain yield. Addition of Ca and B resulted in an increase in leaf B content. Net photosynthesis, stomatal conductance, water use efficiency and carboxylation increased when Ca and B were obtained. Consequently, the improvement of photosynthesis increased the concentration of sugar and protein in the leaf. Improvement in metabolic activity did not affect grain mass per plant, but increased the number of pods per plant and yield. The change in yield was influenced by a cascade of events. The improvement in photosynthetic activity combined with the increase in sugar production may have increased the number of reproductive structures, which directly led to an increase in soybean grain yield.
Descrição
Palavras-chave
Glycine max (L.) Merr, Fertilização foliar, Cálcio, Boro, Floração, Foliar fertilization, Calcium, Boron, Flowering