Fig. 8. Normalized experimental and spherical model semivariograms for lnNO₃–N_aq in the horizontal direction for the (a) control, (b) standard, and (c) high subplot and in the vertical direction for the (d) control, (e) standard, and (f) high subplot. Diamonds represent the experimental semivariograms for the complete NO₃–N_aq dataset; triangles denote experimental semivariograms computed from the dataset without nondetect samples. Solid lines are the spherical semivariogram models fitted to the experimental variograms of the complete data set.