Characteristics of a bunch spear grass (Heteropogon contortus (L). BEAUV.) pasture grazed by cattle in subtropical Queensland.

Abstract

A study of a native pasture of bunch spear grass (HHeteropogon contortus (L.) Beauv.) grazed by beef cattle in subtropical Queensland is reported. The yield and botanical and chemical composition under continuous grazing were recorded over 4 years. Spear grass contributed up to 90 per cent. of the yield of dry matter which ranged from 1 to 2 tons/acre. Approximately 60 per cent. of the total yield was produced between January and April, and there was almost complete absence of growth in the cooler months even when rain occurred. The nutritive value of the forage was low for much of the year, with the crude protein content falling to 2-3 per cent. in the winter. The degree of consumption of forage by stock was low, particularly in the winter, and it was apparent that under the existing form of management the stock had little effect on the pasture. It is concluded that there is little prospect of increasing beef production per acre by grazing management of the native pasture, and that, as the major drawbacks to production stein from the pasture species rather than the climate in which they grow, the logical approach is to replace them by sown grasses and legumes. This involves studies of introduced species and, as many of the soils are of low fertility, attention to plant nutrient deficiencies. Work along these lines is now in progress.