FTIR analysis of soil organic matter to link the turnover of organic inputs with carbon respiration rates

Abstract

Soil amended with different organic inputs or biochar types was analysed by Fourier transform infrared (FTIR) microscopy. Changes in the chemical composition were observed through variations in the spectra and were consistent with changes in carbon dioxide release. Biochar addition strongly decreased the concentration of polysaccharides which was well related to low rates of carbon respiration. Forest waste also induced a low increase on carbon respiration while preserving a high ratio of aromatic carbon in soil. Otherwise, soil amendment with maize straw increased carbon respiration circa ten times while reducing the signal of aromatic carbon. Overall, the results suggest that aromatic compounds and polysaccharides largely determine carbon respiration rates in soil.