Influence of grazing frequency and intensity on tiller appearance and death rates of Lolium perenne L. under subtropical conditions

Abstract

Use of Lolium perenne (perennial ryegrass) in subtropical environments has been limited by its lack of persistence, possibly resulting from poor grazing management. Perennial ryegrass tiller appearance rates (TAR) and tiller death rates (TDR) were monitored under sheep grazing for 2 years. There was a tillering ‘flush’ during the cool-season months, relative to summer. This flush was highest for spring, with a minor trough in winter, and was associated with high TAR and low TDR for these periods. Summer was characterised by high TDR and low TAR. Seasonal patterns of tillering and death were largely unaffected by grazing, although the magnitude of TAR and TDR was manipulated by grazing within a given season. Frequent intense grazing initially produced high TAR, but these were not sustained. Frequent intense grazing resulted in the highest TDR relative to other treatments. Infrequent grazing, irrespective of intensity, resulted in the lowest TDR, particularly during summer, and should be considered by managers to enhance persistence of perennial ryegrass in the subtropics.