Cation Concentrations and Dynamics in the Surface Profile of Two Oxisols after the Application of Vinasse

Abstract

Vinasse is considered the main residue of the sugar and alcohol industry and its application in agriculture provides a considerable amount of potassium and other nutrients to the soil. However, care should be taken when using it for the fertigation of sugarcane fields owing to its high polluting potential. Based on the hypothesis that sandy textured soils promote a greater leaching of cations and therefore a lower cation availability for plants than other soils, the aim of the present study was to evaluate the dynamics and levels of cations along the profile of two Oxisols after vinasse application in elution columns. The experiment was conducted in the Hydraulics and Irrigation laboratory of the Federal Institute of Goiás - Rio Verde Campus, Goiás, Brazil. Two soils were used: Rhodic Hapludox with clayey texture and Oxisol-Typic Hapludox with sandy texture. Rigid polyvinyl chloride (PVC) columns with 0.20 in height and 0.07 m in diameter were used. The columns were dismantled and the chemical analysis of K, Ca, Mg, Na, Cu, Zn, Fe, and Mn nutrient concentrations was performed in the 0.00-0.05, 0.05-0.10, 0.10-0.15, and 0.15-0.20 m layers of the PVC soil column. There was a large K concentration increase along the surface profile of both soils after vinasse application. The Rhodic Hapludox promoted a higher gradient of K concentration than the Oxisol-Typic Hapludox, as well as the highest concentrations along the profile. Conversely, the Oxisol-Typic Hapludox promoted a greater leaching of K than the Rhodic Hapludox. The increase in K concentrations promoted the transport, mainly of Ca and Mg, to deeper layers in both soils. In general, metallic ions had greater mobility in sandier soil, resulting in higher leached contents. Interactions between pH/organic matter and ions could be observed.