RESPONSE OF A FOURTH RATOON SUGARCANE CROP TO NITROGEN, SILICON, AND LIME FERTILIZATION

Abstract

Maximum efficiency of nitrogen (N) is attained when fertilizer is accompanied by silicon (Si). Therefore, the objective of this study was to evaluate the chemical attributes of the soil, the nutritional status, the yield of stalks, and the accumulation of N and Si by a fourth ratoon sugarcane (Saccharum sp.) crop, and the influence of N doses in the presence and absence of Si and lime. The study was carried out at the experimental farm of the UNESP Jaboticabal campus, state of Sao Paulo, Brazil. The experimental design was in a completely randomized block with a 5x2 factorial scheme: five doses of N (0, 40, 80, 120, and 160 kg ha(-1)), and two corrective materials, silicate and lime; with four replications per treatment. The soil was characterized as distrophic Red Latosol, and the sugarcane variety was RB855156. During the experiment, the N (N-NH4+ and N-NO3-) and Si content in the soil, the N and Si content in the leaf, production of stalks, and the accumulation of N and Si in the leaves and stalks were measured. Nitrogen fertilization associated with silicate and limestone increased the levels of N-NO3- and Si in the soil, and improved nutritional status and accumulation of N and Si in leaves and stalks of sugarcane; but, stalk production was lower when using silicate as compared to lime.