Effect of a Single Clipping on the Seed Production Response of Astrebla Spp.

Abstract

A field study was conducted to examine the process by which grazing promotes seed production in Astrebla spp. (predominantly A, lappacea). To simulate grazing, plots within an area of lightly grazed Astrebla grasslands were clipped once, at a range of severities, at the end of the dry season. Grazing pressures ranging from 10% to 90% utilization of A. lappacea were simulated by the clipping treatments. Increasing the severity of clipping gave increased seed production, by increasing the density of inflorescences borne on secondary tillers. In contrast, inflorescence density on main tillers was unaffected by clipping. We concluded that grazing promotes seed production in Astrebla spp. through its effect on inflorescence density on secondary tillers.