Fourier Transform Infrared (FTIR) Spectroscopy of Soil Humic and Fulvic Acids Extracted from Paddy Land Use System

Fourier Transform Infrared (FTIR) Spectroscopy of humic substances shows major components through different peaks. FTIR spectrum of humic acid (HA) showed bands at 3246 cm-1 (H-bonded OH), 1721 cm-1 (C=O of COOH, C=O stretch of ketonic C=O), 1634 cm-1 (COO-, C=O of carbonyl and quinone) and 1102 cm-1 (C-O stretch or OH deformation of COOH). Whereas, fulvic acid (FA) showed peaks at 3497cm-1 (H bonded OH), 2925-2855cm-1 (aliphatic C-H stretch), 2415 cm-1 (extended aliphatic C-H stretch), 1648cm-1 (COO-, C=O of carbonyl and quinone), 1158 cm-1 (aliphatic C-H). Humic acid gives prominent peaks of aromatic components whereas, aliphatic peaks for FA. The distinctiveness of humic substances was influenced by land use management and climatic parameters (temperature and rainfall).