Organic Matter Characterization of Composts From Different Feedstocks

Four composts derived from two different types of raw materials (yard wastes and municipal solid waste, yard wastes and sewage sludges) were analyzed. Degradative and nondegradative techniques (DRIFT, 13C-NMR) were applied to the humic fractions of the compost to study the effect of the starting materials on some chemical and spectroscopic characteristics of the composts. Total nitrogen content and CEC (Cation Exchange Capacity) of the whole composts seem to be related to the origin of composts. Carbon distribution among soluble and insoluble fractions and in fractionated humin (hydrolyzable, nonhydrolyzable alkali soluble, and residual humin) shows differences among composts of the same origin. Total aromaticity determined by humic acids 13C-NMR from composts correlated to humic acids/fulvic fraction and humic acids/humin ratios may be used to measure compost maturity.