Fig. 3. Observed and NLEAP-predicted residual soil NO^-₃–N (RSN) in the bottom of the root depth to 0.9 m soil depth of potato (P) and barley (B) grown in the San Luis Valley. Regression line for the barley growing period (Line B) is y = 7.15 + 0.98x (r² = 0.39, significant at P < 0.13). The potato growing period has an equation as follows (Line P): y = 33.15 + 0.73x (r² = 0.56, significant at P < 0.01). The regression equation for the whole data set P and B (line not shown) is y = 12.5 + 0.95x (r² = 0.78, significant at P < 0.001)