Soil health impact of long-term sugarcane vinasse recycling

The efficient use of vinasse, the primary byproduct of sugarcane ethanol production, is important for the economic and environmental sustainability of the industry. Few studies have quantified the soil health response to long-term vinasse application, even though this byproduct is generally applied as a potassium (K) source in sugarcane fields. The Soil Management Assessment Framework (SMAF) was used to assess the integrated soil health response in soils with contrasting textures. Chemical, physical, and biological indicators were selected, measured, and integrated into a soil health index for clay- and sandy-textured soils in Brazil. Overall, the application of vinasse improved soil health components in both soils. The results showed that the benefits of vinasse go beyond increasing the K content. Vinasse application showed increased soil organic carbon content, nutrient recycling, and soil physical quality. The long-term application of vinasse increased the soil health from 49% to 62% in the clayey soil and from 43% to 61% in the sandy clay soil. The findings therefore revealed the potential of vinasse application to reduce the need for synthetic fertilizer and promote the circular economy and soil health regardless of soil type. This study verifies that the long-term application of vinasse to sandy- and clay-texture soils in Brazil has both economic and environmental benefits because it recycles an important ethanol byproduct and enhances soil health. (AU)