Figure 8. (a) Grain yield (kg ha^–1), (b) shoot dry matter (g plant^–1), (c) harvest index (HI) and (d) root:shoot ratio for an older (‘Pride 5’) and a newer (‘NK N25-J7’) maize (Zea mays L.) hybrid exposed to low N (LN), high N switched to low N at 1 wk presilking (HLN₁), high N switched to low N at 2 wk postsilking (HLN₂), and high N (HN). Different letters indicate significant differences between hybrids per N level (p < 0.05) by t test.