Effect of phosphorus application and of its residue on the yield of sugarcane in a vertisol

Abstract

This work, carried out at Juazeiro, BA, Brazil, aimed at evaluating the effects of 0, 60, 120, 180, 240 and 300 kg/ha of P₂O₅ on the yield, on some technological characteristics of sugarcane and on the residual effect of phosphorus. In all plots, 180 kg/ha of N and 90 kg/ha of P₂O₅ were applied. After harvesting the sugarcane, half of each plot was fertilized with 90 kg/ha of P₂O₅ and all the subplots received 150 kg/ha of N and 90 kg/ha of K₂O. The leaves of 120 day-old plants were analyzed for phosphorus. At harvesting time, the P contents and the pol (%) were determined in the sugarcane juice. The P levels showed a quadratic effect on the yield of sugarcane (R² = 0.94) and on the P concentration in the leaves (R² = 0.98). The yield of sugarcane in the treatments that did not receive a second application of phosphorus varied from 45.31% to 78.93%, as compared to the treatments that had received 90 kg/ha of P₂O₅. Phosphorus concentration in the juice increased with the levels of phosphorus applied. The pol (%) of the juice, however, was not affected.