Fig. 2. Light reflectance measurements from the Spectrum CM1000 reflectance meter plotted against soil NO3–N desorbed from in situ anion exchange membranes, for each sample date. Significant (p < 0.05) linear plateau models are shown for dates on which such models were found. Vertical lines to the x-axes indicate critical value of soil NO3–N. Scale of x-axes varies among plots.