Evaluation of natural annual pastures of Trangie in central western New South Wales, 2. Botanical composition changes with particular reference to Hordeum leporinum

Abstract

The botanical composition of natural pastures stocked at 2.5, 3.7, and 4.9 Merino wethers per hectare was examined over a number of years. Several experiments were conducted in conjunction with the main grazing experiment to determine the relative importance of factors that might be influencing the composition of the pastures. In particular, the importance of nitrogen and sulphur, grazing pressure, and surface mulch were studied. Increased grazing pressure throughout the growing season reduced the proportion of Hordeum leporinum (barley grass) in the pasture. Total soil nitrogen, as affected by stocking rate, did not appear to be important in determining the percentage of barley grass in the pasture. A layer of surface mulch stimulated the germination and growth of barley grass, but not the germination of Erodium crinitum (crowfoot), one of the major broadleaf components of this pasture type.