Changes in pattern and density of perennial grasses in an intensively grazed sown pasture influenced by drought in southern NSW

Abstract

Significant changes in the pattern of distribution and density of perennial ryegrass were recorded in an intensively grazed pasture at 'Wollogorang' near Breadalbane, New South Wales, between March 1963 and May 1965. This period was marked by relatively low rainfall and droughts of moderate and severe intensity. A regular pattern of ryegrass plant distribution characterized the pasture in March 1963. This pattern was modified in subsequent years as the ryegrass cover deteriorated under stress conditions. Phalaris, originally an insignificant component in the pasture, persisted and eventually became the dominant perennial grass. These changes are discussed in relation to rainfall, soil moisture status and the contrasting characteristics of root distribution developed by perennial ryegrass and Phalaris on the 'Wollogorang' site.