Increasing the perennial grass component of native pastures through grazing management in the 400 - 600mm rainfall zone of central western NSW

Abstract

Native grass-based pastures in the 400–600 mm rainfall zone of central NSW are an important basis for extensive grazing industries. However, over time they have been invaded by exotic weeds. This study aimed to evaluate several grazing strategies for the maintenance or improvement of native grasslands based on pasture productivity and species diversity. Seven grazing strategies, ranging from set stocking to permanently removing stock, were employed to evaluate the strategy that would best maintain a high proportion of desirable perennial grass species. Grazing treatments were evaluated based on their effects on pasture composition and on the density of selected key grass species such as Enteropogon acicularis (Lindl.) Lazar. (curly windmill grass). Managing the utilisation of the key desirable species E. acicularis combined with weed control was the most successful strategy in terms of increasing the density of the key species, although no treatment increased the proportion of desirable perennial grasses and desirable broadleaf species. This was followed by a ‘farmer’s choice’ strategy, which involved combining phosphorus fertiliser application, weed control and rest from grazing. In contrast, strategies that involved either a ‘summer lockup’ or ‘weed control’ alone performed poorly. It is concluded that native pastures in this region could be rehabilitated, and their productivity restored, by following strategies that provide rest from grazing, based on the utilisation levels of key, species combined with control of annual weeds.