Effects of boron application on yield, foliar B concentration, and efficiency of soil B extracting solutions with boron application in a Xanthic Ferralsol cultivated with banana in Central Amazon

Boron is known to play an important role for the structure of cell wall, membranes and the integrity and functions of membranes in plants. In soil, the hot water B extraction method has been extensively used for evaluation of soil B status. However, difficulties with this method result in low accuracy and precision of extraction of available boron (B) in soil. The objective of this study was to evaluate the yield, foliar concentration, and efficiency of B extracting solutions and the effect of B fertilization on B uptake in banana leaves and fruits, subgroup Cavendish (AAA), cultivated in a Xanthic Ferralsol (dystrophic Yellow Latosol), in the Amazonas State, Brazil. The experimental design was a completely randomized split plot, comprising four boron rates (0, 4, 8, and 12 kg ha-1), and two harvest cycles (sub-treatments), with four replicates. Available boron was determined with seven extractant solutions: Mehlich 1, Mehlich 3, hot water, HCl 0.05 mol L-1, HCl 0.1 mol L-1, HCl 5.0 mol L-1 and KCl 1.0 mol L-1. The application of B fertilizer increased the yield and B concentration in leaves and fruits. Hot water and KCl 1.0 mol L-1 were the most efficient extracting solutions for the determination of available B in soil. The application of 3.4 kg B ha-1 in first cycle and 1.3 kg B ha-1 in second cycle guarantees an adequate nutritional status in banana plant