Comparative productivity of perennial and annual pastures under continuous grazing by sheep

Abstract

The productivity of sheep grazing clover based pastures with and without sown perennial grasses was evaluated at two sites in the 500-550 mm rainfall region of south-western Australia. The grasses were Phalaris aquatica, Dactylis glomerata, Lolium perenne, and Festuca arundinacea (one site only). There were significant differences between the effects of the pastures on liveweight change in each year. The inclusion of perennial grasses tended to reduce liveweight loss during autumn and early winter, when the range of differences in weight change was commonly 4-6 kg/head. Most consistent results were obtained in the sheep grazing P. aquatica and F. arundinacea pastures; D. glomerata, L. perenne, and annual pastures were more variable between seasons and between sites. Significant differences were also found in wool production. Sheep grazing F. arundinacea and P. aquatica showed mean adjusted fleece weights 0.29-0.76 kg/head greater than those from sheep grazing annuals. At the end of the experiments, survival of sown grasses at the respective sites was 17 and 25 plants/m2 for P. aquatica, 43 and 29/m2 for D. glomerata, 27/m2 for F. arundinacea, and less than 1/m2 for L. perenne. The contribution of perennials to total herbage tended to decline with time. The results suggest that advantages in liveweight and wool production may be gained by the addition of some perennial grasses to the pastures of the region.