Fig. 1. Spectra for soil (a) and litter (b) extracted with 0.25 M NaOH, 0.25 M NaOH plus 6:1 Chelex to soil or litter (wt. basis), or 1:1 0.5 M NaOH plus 0.1 M EDTA. Spectra are the 3.2 s recovery delay time data for each respective interleaved series of saturation-recovery experiments.