Defoliation of Young Branch and Parent Stolons of White Clover in Rotationally Grazed Pastures

This study was undertaken to examine the relative severity of defoliation of young branches (those comprising <4 nodes) and parent stolons of white clover (Trifolium repens L.) in rotationally grazed pastures stocked al either 2.5, 5.0 or 7.5 bulls/ha. On 7 occasions over a year, the defoliation of expanded leaves of parenl and branch stolons was assessed using tagged stolons. Petiole length of leaves ,vas measured before grazing. Leaves of young branch stolons (43% of the total number of leaves defoliated) were less severely defoliated than leaves of parent stolons (64%). Defoliation of branch stolon leaves was relatively greater at the higher stocking rates which had lower residual herbage biomasses. Before grazing, the mean petiole length of young branch leaves was only 42% that of leaves of parent stolons. It was concluded that reduced defoliation of young branch leaves resulted from their lower position in the sward and was likely to enhance the probability of survival of young branch stolons.