Efficiency of soluble and insoluble sources of manganese for soybean nutrition in the Brazilian Cerrado

Eficiência de fontes solúveis e insolúveis de magnésio para nutrição da soja no Cerrado brasileiro

Abstract

The objective of this work was to evaluate the efficiency of sources and rates of soluble (MnSO₄.H₂O) and insoluble (MnCO₃) manganese on the processes of uptake, transport, and redistribution of this nutrient in soybean, as well as on crop yield, in Cerrado soil. The experimental design was randomized complete blocks in a 4×2 factorial arrangement – four rates (150, 250, 350, and 450 g ha⁻¹) × two sources (MnSO₄.H₂O and MnCO₃) of Mn –, with four replicates. In the 2015/2016 and 2016/2017 crop seasons, foliar fertilizations were carried out on the third trifoliate leaflet, and Mn content and soybean yield were evaluated. In both crop seasons, Mn foliar fertilization increased the contents of the nutrient in leaves, stems, and grains, but did not affect grain yield and dry matter production. The maximum Mn contents in leaves were obtained with rates between 150 and 450 g ha⁻¹. The fertilization with MnSO₄.H₂O increased Mn uptake, transport, and redistribution in the plant, with a performance superior to that of MnCO₃. Foliar fertilization with MnSO₄.H₂O in soybean, in a Cerrado soil, increases Mn contents in the leaves but not yield and dry matter production.

Index terms:
Glycine max ; manganese carbonate; manganese sulfate; Mn contents