Comparison of the carbon-sequestering abilities of pineapple leaf residue chars produced by controlled combustion and by field burning

► The chemical properties and yield of char produced by CF and CL were used to estimate the carbon-sequestering abilities. ► The char produced by CL had higher total C, lignin content and char yield than the char produced by CF. ► The N compounds reacted with other functional groups, and forming more condensed aromatic compounds in the char produced by CL. ► Lignin dominated the C found in the char produced under CL conditions, suggesting that the decomposition would be slow. ► In order to sequester C and to produce more stable char, PLR should be combusted in a controlled process.