Carbon storage in irrigated and rainfed sugarcane production systems with vinasse application

Improper soil management for the development of important crops worldwide can jeopardize carbon (C) storage and soil organic matter (SOM) health. It was postulated that the application of vinasse to sugarcane soil under the control of agricultural machinery could increase C stocks and improve aggregate stability index, soil porosity and density, thus ensuring better root penetration. Therefore, in this study, the management system of sugarcane based on rainfed with vinasse application (RV), irrigated (I) and irrigated with vinasse application (IV) was studied in a tropical environment to determine the C stocks and the physical and chemical properties of the soil. The experimental design was randomized blocks with five replicates, and the organic C contents and stocks, soil density, total porosity, soil resistance to root penetration, and aggregate stability index (ASI) of sugarcane within rows and between rows were analyzed at 0–10- and 10–20- cm depth. The RV and IV treatments promoted the same potassium concentrations in the row and between the rows of sugarcane cultivation. The IV exhibited the highest soil ASI (74% at 0–10- and 77% at 10–20-cm depth) and stored approximately 70% more carbon than the I management. The use of sugarcane vinasse preserved the physical conditions of the soil, particularly in the inter-row area, by reducing surface layer compaction and increasing soil moisture and porosity, thereby representing a more sustainable long-term management system.