Fig. 4. Effect of residence time (t_R = 1, 3, or 7 d) on the weekly N fertilizer uptake per plant, (A) fall 2004 and (B) spring 2006. Calculated cumulative N uptake per ha during (C) fall 2004 and (D) spring 2006 of sweet corn. Error bars represent standard error from the mean, n = 4. Treatment means followed by the same letter are not different according to Duncan's test at P 0.05.