Analysis of the vertical distribution of RW showed
that it was consistently higher in the top soil layer (0-
20 cm) of SP plots than in plots subjected to any other
treatment, for both cultivars at the four growth stages
(Fig. 2). The proportion of RW found in the deep soil
layers (30-100 cm) was higher for the drought-tolerant
cultivar CH58 than for the drought-sensitive cultivar
XY22 and the difference was most pronounced under
the deep treatments.
Analyses of temporal changes revealed that the proportion
of RW in deep soil layers (30-100 cm) increased
notably after the jointing stage under the DP and DBP