Effect of clipping and fertiliser addition on the feed value of Chilean needle grass ('Nassella neesiana') during reproductive growth stages

Abstract

Concern about the invasion of pastures in southeastern Australia by Chilean needle grass ('Nassella neesiana' (Trin. & Rupr.) Barkworth) began to mount in the 1970s. Native to temperate South America, Chilean needle grass can completely overrun pastures resulting in canopy cover of up to 60%. Such infestations lead to a substantial reduction of stock carrying capacity during late spring and summer when the weed produces large quantities of unpalatable flower stalks. By the 1990s many farmers in New South Wales and Victoria found that they had expanding cover of Chilean needle grass on their properties. Moreover, the weed has been invading conservation areas comprising native grasslands, grassy woodlands and riparian vegetation in many areas. The main problem encountered in the management of pastures dominated by Chilean needle grass is the production of large numbers of unpalatable flower stalks during summer, which are actively avoided by stock, and have sharp seeds which can penetrate the hides of sheep. As 'N. neesiana' is palatable for much of the year, grazing management of this species has been identified as a potential management tool requiring investigation. The project aims to maximise the feed utilisation of Chilean needle grass, whilst limiting the production of viable seeds, using a range of cultural techniques and grazing strategies that incorporate different classes of stock. This paper describes an experiment that evaluated the feed value of Chilean needle grass, when compared with cocksfoot ('Dactylis glomerata' L.), under clipping and fertiliser regimes during the reproductive growth stages.