Potential for agronomic and environmental use of biochars derived from different organic waste

The application of biochars in soils has been generating excitement within the scientific community due to its benefits in both agronomic and environmental areas. The current challenge is to select suitable raw materials and preparation procedures to obtain biochars with appropriate properties for specific purposes. Therefore, the objective of this study was to characterize the properties of biochars derived from twenty different types of organic waste and correlate these properties with their potential agronomic and/or environmental use. Twenty types of raw materials available in the Brazilian Amazon were placed in closed porcelain crucibles and subjected to pyrolysis in a muffle furnace set at 350 °C for 2 h. Chemical, physicochemical, and spectroscopic analyses were conducted on the produced biochars. As a result, biochars derived from poultry litter, annatto seed, passion fruit peel, and coffee husk are suitable for improving the fertility of nutrient-deficient soils thanks to their high ash and nutrient contents, elevated pH, and low C/N ratios. Biochars derived from sugarcane bagasse and wood residues were characterized by their high carbon content and aromaticity, making them difficult to mineralize in soil. Consequently, these biochars show promise for environmental use, with the potential to sequester C and mitigate greenhouse gas emissions.