Drought resistance effects on species composition of an annual pasture in a dry monsoonal climate.
The drought resistance of young seedlings of Stylosanthes humilis and Digitaria ciliaris was investigated in the field at Katherine, Northern Territory, and in controlled environment chambers. S. humilis survived drought better than did D. ciliaris. This difference could not be explained by differences in resistance to heat or desiccation, or in initial rates of root penetration. It might be due in part to the slower leaf development and faster root growth of S. humilis. It is concluded that drought avoidance mechanisms are more important for survival than physiological resistance, and that differences in field resistance are important in determining the proportions of the species in pasture.