Fertirrigation with manganese in beet

Abstract

No study has investigated the fertilization of beet with manganese (Mn) in the Brazilian semi-arid region. In this study, we evaluated the agronomic performance of manganese fertigated beet in Mossoró, Rio Grande do Norte. The experiments were conducted at Fazenda Experimental Rafael Fernandes in 2019 and 2021, and the study had a complete randomized block design with five treatments (0, 3, 6, 9, and 12 kg ha–1 Mn) and four replications. The Mn content increased in foliar diagnosis with fertilization. The accumulation of dry mass and the number of leaves did not differ significantly as a function of the dose. The highest total (21.59 t ha–1) and commercial (20.55 t ha–1) yields of tuberous roots were obtained with 6 kg ha–1 Mn. The adverse effects of excess Mn were expressed in the lower total and commercial productivity of beet fertilized with more than 6 kg ha–1 Mn. The accumulation of Mn in the tuberous roots was not affected by fertilization. In the leaves and the whole plant, the maximum accumulation occurred when 12 kg ha–1 Mn was applied. Although Mn did not influence the content of soluble solids, the pH of the tuberous roots of plants fertilized with 6 kg ha–1 Mn decreased, and the dose with the highest total and commercial productivity had a lower content of soluble sugars. Our findings suggest that treatment with 6 kg ha–1 Mn is optimum for the beet crop.

Não há na literatura recomendações de adubação com manganês (Mn) para beterraba estabelecidas no semiárido brasileiro. Objetivou-se avaliar o desempenho agronômico de beterraba fertirrigada manganês em Mossoró, RN. Foram desenvolvidos experimentos na Fazenda Experimental Rafael Fernandes nos anos de 2019 e 2021, delineados em blocos casualizados completos com cinco tratamentos (0, 3,0, 6,0, 9,0 e 12,0 kg ha–1 de Mn) e quatro repetições. Houve aumento no teor de Mn na diagnose foliar com a adubação. O acúmulo de massa seca e o número de folhas não diferiram estatisticamente em função das doses. A maior produtividade total (21,59 t ha–1) e comercial (20,55 t ha–1) de raiz tuberosa foi obtida com 6,0 kg ha–1 de Mn. O efeito deletério do excesso de Mn foi expresso na menor produtividade total e comercial de beterraba adubada com mais que 6,0 kg ha–1 de Mn. O Mn acumulado na raiz tuberosa não foi influenciado pela adubação. Nas folhas e na planta inteira, o acúmulo máximo ocorreu na dose 12,0 kg ha–1 de Mn. O Mn não influenciou no conteúdo de sólidos solúveis, mas reduziu o pH e, a raiz tuberosa das plantas adubadas com 6,0 kg ha–1 de Mn, dose com maior produtividade total e comercial, tiveram menor teor de açúcares solúveis. Recomenda-se adubação com 6,0 kg ha–1 de Mn para a cultura da beterraba.