Unburned ratoon sugarcane yield according to gypsum and vinasse doses

Abstract

Understanding the influence of sugarcane straw over the application dynamic of vinasse and correctives is essential for an effective management of the production system. This study aimed at evaluating soil fertility, stalk yield and technological quality of ratoon sugarcane (2nd cycle), according to vinasse and gypsum application, in an Oxisol, in the Northwest São Paulo State, Brazil. The study was carried out with the RB867515 cultivar and the experimental design was randomized blocks with four replications, in a 2x3 factorial scheme, i.e., with and without gypsum (1.0 t ha^-1) and vinasse application in three doses: 0.0 m³ ha^-1 (control), 100.0 m³ ha^-1 and 200.0 m³ ha^-1. The gypsum application increased the Ca²⁺, Mg²⁺, SO₄^2-, pH and base saturation and reduced the contents of Al³⁺, in the 0-0.20 m and 0.20-0.40 m layers, and increased the SO₄^2- content in the 0.40-0.60 m layer, after 180 and 360 days, respectively. The gypsum plastering and the vinasse application did not increase the stalk yield nor improved its technologic quality.