CHARACTERIZATION OF PARTICLE-SIZE FRACTIONS OF PEAT - AN INTEGRATED BIOLOGICAL, CHEMICAL, AND SPECTROSCOPIC APPROACH

Various botanical, microbiological, chemical, and spectroscopic analyses were made on particle size fractions of peat with different botanical composition and degree of decomposition. Seven fractions between 2 mm and < 0.045 mm were included in the study, which showed that the properties of all fractions were mainly dependent on the peat type of each original peat sample. The botanical composition varied between peat types, and some distinction between size fractions could also be seen regarding the type of plant tissue. The finest fraction of all peat types (< 0.045 mm) contained only amorphous particles. This fraction gave dramatically higher respiration rates than all other fractions. C-13 CP/MAS NMR and chemical measurements indicated that the main variation was a decrease in carbohydrates with decreasing particle size. Homogeneous aliphatic chains, together with carbonyl groups, were the most prominent feature of the finest fraction as probed by the NMR measurements.