Fig. 4. (A) Carbon-13 direct polarization magic angle spinning (13C DP/MAS) and (B) 13C cross polarization magic angle spinning (CP/MAS) and spectra for litter samples. Spectra for the humic acid and humin fractions are not shown.
Fig. 4. (A) Carbon-13 direct polarization magic angle spinning (13C DP/MAS) and (B) 13C cross polarization magic angle spinning (CP/MAS) and spectra for litter samples. Spectra for the humic acid and humin fractions are not shown.