Fig. 2. Changes in nitrate N concentration with high level of glucose C (970 mg L^-1) in the subirrigation water at the (a) 40-cm, (b) 60-cm, and (c) 85-cm depths (Experiment I, Stage 1). The error bars in the figure and all other subsequent graphs show the standard deviation (SD), showing that 68% of the data obtained (assuming a normal distribution) lie within ±1 SD from the mean (Zolman, 1993; SAS Institute, 1989)