Figure 1

¹³ C-CPMAS-NMR spectra of compost (C ₁ to C _OW ) samples. Vertical lines delimitate six different spectral regions: aliphatic and aromatic carboxyl C (Cx C, 190 to 166 ppm); oxygen-substituted aromatic C from lignin and non-hydrolyzable tannins, phenolic and O-aryl (Ph C, 165 to 146 ppm); unsubstituted and alkyl-substituted aromatic C, aryl (Ar C, 145 to 111 ppm); anomeric C and di-Oalkyl and oxidized and/or carbohydrate C, O-alkyl (O-Al C, 110 to 61 ppm); methoxyl/N-alkyl (Me C, 60 to 46 ppm); and aliphatic C, alkyl (Al C, 45 to 0 ppm).