Fig. 8 Series of cross-polarization-total sideband suppression (CP–TOSS) spectra of humic acids (HAs) of different origins, International Humic Substances Society (IHSS) Florida peat and plant-extracted materials (PEMs), as indicated
Fig. 8 Series of cross-polarization-total sideband suppression (CP–TOSS) spectra of humic acids (HAs) of different origins, International Humic Substances Society (IHSS) Florida peat and plant-extracted materials (PEMs), as indicated