Effect of chemical fertilization on plant growth and on fruit production of the "Grand Naine" banana cultivar.

Abstract

The aim of this study was to analyze the effects of increasing amounts of nitrogen (N), phophorus (P) and potassuim (K) on the growth and yield of “Grand Naine” banana cultivar, in relation to the soil and climate conditions of Teresina, Piauí, Brazil. This study was carried out at Embrapa Meio-Norte’s experimental area. The soil was classified as Dystrophic Red-Yellow Argisol. Central compound randomized blocks were used as the experimental design, with three replications. The dosis of fertilizer were: 0; 100; 200; 300 e 400 kg of N ha-1.cycle-1; 0; 50; 100; 150 e 200 kg of P2O5 ha-1.cycle-1 and 0; 150; 300; 450 e 600 kg of K2O .ha-1.cycle-1, applied as urea, triple superphosphate and potassium chloride, respectively. The evaluation of growth, after 240 days, indicated that only N and K influenced (p<0,05) the height and circumference of the pseudotrunk. It was, also, identified that a quadratic model fitted better to both variables. In the first production cycle, an isolated effect of N and P on fruit production was observed with maximum yield of 48,000 kg.ha-1. This was obtained with the combination of 200 kg of N ha-1 and 300 kg of K2O ha-1. In the second production cycle, the addition of both P and K yields a technical optimum of 58,350 kg.ha-1. This was obtained with the combined dosis of 123.83 kg of P2O5 ha-1 and 344.76 kg of K2O ha-1. Therefore, recommendations for fertilizing banana trees need to be based on the production cycle; higher for N and K fertilization in the first production cycle and higher for P and K in the second cycle.