Grazing Management of Native and Natural Pastures on the Northern Slopes of New South Wales

Abstract

Native and natural pastures comprise 70% of the 2.9 million ha of agricultural land on the Northern Slopes of New South Wales. These pastures are dominated by warm season frost-susceptible native perennial grasses that have a low availability of winter green forage. Little is known of the grazing value of the individual native perennial grasses, their response to fertility and their ecology and phenology. The responses of individual species to management is largely unknown and there are few objective data on which to assess their desirability or undesirability as pasture species. If valuable native grasses for grazing could be identified in these pastures then management could well be directed at increasing their abundance. Studies were conducted on the eight dominant native perennial grasses of the region to obtain preliminary data on which to classify the desirability of these grasses as pasture species. The grasses studied were the warm season native perennial grasses 'Aristida ramosa' R.Br. (wiregrass), 'Bothriochloa macra' (Steud.) S.T. Blake (redgrass), 'Dichanthium sericeum' (R.Br.) A. Camus (bluegrass), 'Sporobolus elongatus' R.Br. (slender rat's tail), 'Eragrostis leptostachya' Steud. (lovegrass), and 'Chioris truncata' R.Br. (windmill grass), and the yearlong green native perennial grasses 'Danthonia linkii' Kunth (wallaby grass) and 'Stipa scabra' Lindl. (corkscrew grass). Native and natural pastures are complex plant communities containing up to 100 species within a single paddock. Many of these species have similar leaf characteristics making accurate identification difficult and often data may need to be collected for both major and minor species in the pasture. Existing techniques for measuring species herbage mass are often inappropriate. Two methods of estimating the herbage mass of native perennial grasses were devised and tested. Both involved the harvesting of individual plants in the field and the measurement of their components of herbage mass (basal area and mass per unit of basal area) and the number of plants per unit area (plant density).