Net and Potential Nitrogen Mineralization in Soil with Sugarcane Vinasse

Abstract

The increasing ethanol production brings many advantages to Brazil. However, it generates high quantities of vinasse from 10 to 15 l per liter of alcohol produced. This residue is applied as a fertilizer in sugarcane crops but, it presents a potential risk to soil quality when high doses of vinasse are applied in the same area over years. So, one solution would be to transport it to distant locations, but this would mean an increase in costs. Thus, concentrated vinasse, wherein the volume is reduced by evaporation process, becomes a viable alternative and is being increasingly used by sugarcane mills in Brazil. The aim of this study was to evaluate the net nitrogen mineralization and potential nitrogen mineralization of soil that received three doses of concentrated and not concentrated vinasse. The not concentrated vinasse is a good alternative to be applied, but higher doses promote N losses by denitrification due to the high water content. The highest values of potential nitrogen mineralization and, lowest values of constant of mineralization in the treatments with concentrated vinasse indicate that this residue releases N at a slower speed than in treatments with not concentrated vinasse, suggesting that there will be N availability in the subsequent crops.