Fig. 4. Root pools of asparagine (A, B), proline (C, D), arginine (E, F), and histidine (G, H) of two alfalfa cultivars (AC Caribou and WL 225) harvested twice or three times with the third harvest taken at 400, 500, or 600 GDD after the second harvest. Pools were calculated at each harvest date for the corresponding harvest treatments (Harvests): on 7 Aug. 1997 for plants harvested twice, and on 8 Sept., 17 Sept., and 7 Oct. 1997 for plants harvested at 400, 500, or 600 GDD after the second harvest, respectively. Pools were also calculated for all harvest treatments on 10 Nov. 1997, 12 Jan. 1998, and 11 Mar. 1998. Vertical bars indicate SEM for each sampling date.