Fig. 2. Observed and NLEAP-predicted residual soil NO^-₃–N (RSN) in the root zone of potato (P) and barley (B) grown in the San Luis Valley. Regression line for the barley growing period (Line B) is y = 6.19 + 0.72x (r² = 0.70, significant at P < 0.01). The potato growing period has an equation as follows (Line P): y = 8.49 + 0.82x (r² = 0.43, significant at P < 0.05). The regression equation for the whole data set P and B (line not shown) is y = 4.7 + 0.86x (r² = 0.71, significant at P < 0.001)