Fig. 3. Solid-state ¹³C cross polarization and magic angle spinning (CPMAS) with total suppression of sidebands (TOSS) (dotted line) and dipolar dephasing (DD)–TOSS (full line) spectra of mobile humic acids (MHA) and calcium humates (CaHA) from one soil with no annual irrigated rice crops (dryland rice) and one soil with three irrigated rice crops per year (Long-Term Continuous Cropping Experiment [LTCCE] Control).