Sugarcane Response to Boron and Zinc in Southeastern Brazil

Abstract

The application of micronutrients on the sugarcane crop in Brazil is not a widespread practice, due to the few studies developed under Brazilian conditions. Nevertheless, the crop advance to lower fertility soils and the introduction of varieties with greater yield potential will change the nutrient management. In this context, two experiments were developed with boron (B) or zinc (Zn) application with the aim of evaluating yield, technological attributes and biometric indexes of sugarcane during the plant cane cycle and the residual effect of this fertilization on the first ratoon. The experiments were developed in Pirassununga, Sao Paulo, Brazil. In both trials, the doses of B (2 and 4 kg ha−1) and Zn (3 and 6 kg ha−1) were applied in top dressing. The crop was harvested around 13 months after the treatments application and, after the first harvest, all the plots received the same doses of N, P2O5 and K2O, to evaluating the residual effect on the first ratoon. The B application reduced the above ground biomass, TSS (tons of sugarcane stalks per hectare) and sugar yield in the plant cane. However, the Zn fertilization improved the stalk technological quality, as well as providing a residual effect, increasing the above ground biomass, TSS and stalk yield (dry matter). The dry matter accumulation showed three growth phases during the plant cane cycle, similar to the B and Zn accumulation. The fertilization with B, especially with high solubility sources, must be careful to avoid yield reduction.