Fig. 6. Pools of total amino acids in roots of two alfalfa cultivars, AC Caribou (A,C) and WL 225 (B,D), harvested either only twice during the summer, or three times with the third harvest taken in the fall 400, 500, or 600 growing degree days (GDD) after the second summer harvest. Samples were taken at the experimental sites of Pintendre (A,B) and Normandin (C,D), in fall 1997, spring 1998, fall 1998, and spring 1999. Vertical bars indicate ± SE of the mean for each sampling date. ND, not determined since there was no sample in the three harvest treatments at Normandin in spring 1999. At this date, SEMs were calculated with results from the two harvest samples.