Fig. 3 Root dry weight of Kentucky bluegrass under optimum temperature and well-watered conditions (control), drought (D), heat (H), and the combination of two stresses H+D in the 0- to 20-, 20- to 40-, and 40- to 60-cm soil layers at 25 d of D or H alone and 12 d of the combined stresses. Means followed by the same letters within each soil layer were not significantly different based on LSD test