Suplementação via foliar de nutrientes aumenta a eficiência fisiológica e a produtividade de grãos do milho de segunda safra
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Data
2023-06-01
Autores
Vilela, Leila Bernart
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O milho é considerado uma das culturas de maior importância em área cultivada no Brasil. Para satisfazer a demanda de alimentos, com o aumento populacional é preciso um aumento de cerca de 60% na produção global de alimentos, sem aumentar a área destinada ao cultivo, para que isso ocorra, as adoções de novas tecnologias são necessárias para o aumento de produtividade. Com isso a utilização da tecnologia de adubação foliar, minimizando os efeitos deletérios na planta, com temperaturas elevadas, estresse hídrico e radiação solar, com ação estimulante na planta é uma ferramenta necessária na agricultura moderna e sustentável. Dessa forma, o objetivo deste trabalho foi avaliar os efeitos fisiológicos com a presença da aplicação foliar de macronutrientes nitrogênio, fósforo e potássio e os micronutrientes boro, manganês e zinco e ausência da aplicação na cultura do milho em dois anos agrícolas, dividindo-se em dois capítulos. O primeiro capítulo foi realizado um estudo com nitrogênio, fósforo e potássio foliar em milho na safra 2019 e 2020. O segundo capítulo refere-se ao estudo com boro, manganês e zinco na mesma cultura e anos agrícolas do estudo 1. Os experimentos foram realizados em campo na Fazenda Experimental Lageado pertencente a Faculdade de Ciências Agronômicas da Universidade Estadual Paulista “Júlio de Mesquita Filho”. As aplicações ocorreram nos estádios fisiológicos V8. As avalições realizadas no primeiro experimento foram o status nutricional das folhas de milho, enzimas fotossintéticas [enzima ribulose-1,5-bifosfato carboxilase/oxigenase (Rubisco) e fosfoenolpiruvato carboxilase (PEPcase)], taxa fotossintética líquida, A; condutância estomática, gs; concentração subestomática de CO2, Ci; transpiração foliar, E; eficiência no uso da água, WUE; e eficiência de carboxilação, A/Ci de plantas de milho, concentração de proteínas totais e concentração de açúcares solúveis totais, prolificidade, número de grãos por espiga, peso cem grãos e rendimento de grãos. No segundo experimento seguiu as mesmas avaliações, porém inseriu a avaliação de enzimas antioxidantes (peróxido de hidrogênio (H2O2), malondialdeído (MDA), superóxido dismutase (SOS), catalase (CAT)). O NPK foliar proporcionou aumento da fotossíntese liquida, condutância estomática, eficiência do uso da água e carboxilação. A aplicação de B, Mn e Zn foliar contribuiu para aumentar as enzimas antioxidativas, reduzir o estresse oxidativo e melhorar o uso da energia acumulada da fotossíntese. Os resultados obtidos nesta pesquisa representam uma boa estratégia para diminuir o estresse causado por fatores abióticos e aumentar a produtividade das culturas.
Maize is considered one of the most important crops in cultivated area in Brazil. To satisfy the demand for food, with the population increase, it is necessary an increase of about 60% in the global production of food, without increasing the area destined to the cultivation, for that to happen the adoption of new technologies are necessary for the increase of productivity. Thus, the use of foliar fertilization technology, minimizing the deleterious effects on the plant, with high temperatures, water stress and solar radiation, with a stimulating action on the plant, is a necessary tool in modern and sustainable agriculture. Thus, the objective of this work was to evaluate the physiological effects with the presence of foliar application of the macronutrients nitrogen, phosphorus and potassium and the micronutrients boron, manganese and zinc and the absence of application in the corn crop in two agricultural years, divided into two chapters. The first chapter was a study with nitrogen, phosphorus and potassium leaf in corn in the 2019 and 2020 harvest. The second chapter refers to the study with boron, manganese and zinc in the same crop and agricultural years of study 1. The experiments were carried out in the field at the Experimental Farm Lageado belonging to the Faculty of Agronomic Sciences of the Universidade Estadual Paulista “Júlio de Mesquita Filho”. The applications occurred in physiological stages V8. The evaluations carried out in the first experiment were the nutritional status of corn leaves, photosynthetic enzymes (Rubisco and PEPcase), net photosynthetic rate, A; stomatal conductance, gs; substomatal concentration of CO2, Ci; leaf transpiration, E; water use efficiency, WUE; and carboxylation efficiency, A/Ci of maize plants, total protein concentration and total soluble sugar concentration, prolificacy, number of grains per ear, grain weight and grain yield. In the second experiment, the same evaluations were followed. The second experiment followed the same estimates, but included the evaluation of antioxidant enzymes (hydrogen peroxide (H2O2), malondialdehyde (MDA), superoxide dismutase (SOS), catalase (CAT)). Leaf NPK increased net photosynthesis, stomatal conductance, water use efficiency and carboxylation. The application of foliar B, Mn and Zn contributed to increase antioxidative enzymes, reduce oxidative stress and improve the use of accumulated energy from photosynthesis. The results obtained in this research represent a good strategy to reduce the stress caused by abiotic factors and increase crop productivity.
Maize is considered one of the most important crops in cultivated area in Brazil. To satisfy the demand for food, with the population increase, it is necessary an increase of about 60% in the global production of food, without increasing the area destined to the cultivation, for that to happen the adoption of new technologies are necessary for the increase of productivity. Thus, the use of foliar fertilization technology, minimizing the deleterious effects on the plant, with high temperatures, water stress and solar radiation, with a stimulating action on the plant, is a necessary tool in modern and sustainable agriculture. Thus, the objective of this work was to evaluate the physiological effects with the presence of foliar application of the macronutrients nitrogen, phosphorus and potassium and the micronutrients boron, manganese and zinc and the absence of application in the corn crop in two agricultural years, divided into two chapters. The first chapter was a study with nitrogen, phosphorus and potassium leaf in corn in the 2019 and 2020 harvest. The second chapter refers to the study with boron, manganese and zinc in the same crop and agricultural years of study 1. The experiments were carried out in the field at the Experimental Farm Lageado belonging to the Faculty of Agronomic Sciences of the Universidade Estadual Paulista “Júlio de Mesquita Filho”. The applications occurred in physiological stages V8. The evaluations carried out in the first experiment were the nutritional status of corn leaves, photosynthetic enzymes (Rubisco and PEPcase), net photosynthetic rate, A; stomatal conductance, gs; substomatal concentration of CO2, Ci; leaf transpiration, E; water use efficiency, WUE; and carboxylation efficiency, A/Ci of maize plants, total protein concentration and total soluble sugar concentration, prolificacy, number of grains per ear, grain weight and grain yield. In the second experiment, the same evaluations were followed. The second experiment followed the same estimates, but included the evaluation of antioxidant enzymes (hydrogen peroxide (H2O2), malondialdehyde (MDA), superoxide dismutase (SOS), catalase (CAT)). Leaf NPK increased net photosynthesis, stomatal conductance, water use efficiency and carboxylation. The application of foliar B, Mn and Zn contributed to increase antioxidative enzymes, reduce oxidative stress and improve the use of accumulated energy from photosynthesis. The results obtained in this research represent a good strategy to reduce the stress caused by abiotic factors and increase crop productivity.
Descrição
Palavras-chave
Zea mays L., NPK, adubação foliar, fotossíntese, estresse oxidativo, foliar fertilization, photosynthesis, oxidative stress