Can 'Nassella neesiana', Chilean needle grass, be incorporated into a grazing management system in Australia?

Abstract

In Australia, 'Nassella neesiana' (Chilean needle grass) is considered a weed of pastures, whereas, in its native Argentina, it is a desirable component of pastures. This study made a preliminary assessment of its value as a pasture and discusses the potential for its abundance to be controlled by grazing management. As a measure of pasture productivity, regrowth herbage mass was compared between 'N. neesiana' and 'Festuca arundinacea'. 'F. arundinacea' was more productive in all but one sampling period in October/November1995. The cumulative regrowth herbage mass of N. neesiana over a 50 week period was 24.3% lower than that of F. arundinacea (0.1986 compared with 0.2623 g cm² basal area year⁻¹). The crude protein of N. neesiana green leaf samples ranged from 12.7 to 16.6% while digestible dry matter ranged from 58 to 66%, again somewhat lower than comparable values for 'F. arundinacea'. Nevertheless, these figures, combined with the fact that 'N. neesiana' had a high basal cover (20%), resulted in the production of a large amount of reasonable quality feed. On a whole paddock basis average regrowth production of 'N. neesiana' was calculated to be 2296 kg ha⁻¹ year⁻¹, It is suggested that a cell grazing approach with high stock densities for one to three days followed by rest periods of 40 to 90 days, depending on seasonal conditions and anticipated seasonal growth rates, could result in a reduction in abundance of 'N. neesiana' and an increase in abundance of more valuable competing perennial grasses.