Assessment of management options for Chilean needle grass in sheep-grazing systems

Chilean needle grass [Nassella neesiana (Trin. & Rupr.) Barkworth; CNG] is a perennial spear grass that has invaded pastures in south-eastern Australia and can lead to a substantial reduction of stockcarrying capacity during the summer months. This study examined a range of grazing, herbicide and pasture resowing options, alone or in combination, on CNG and introduced pasture grass basal cover, for several CNG-infested sites in south-eastern Australia. At each site, options were chosen on the basis that they were most likely to control the CNG infestation while maintaining a productive sheep-grazing enterprise on grass pastures. After 2years of management, the reduction in CNG basal cover in set stock plots that were sprayed with flupropanate, versus those not sprayed, ranged from non-detectable to a reduction of 80%, depending on site location. After 5years of management, the reduction ranged from zero to 50%. Grazing management or sowing of competitive pastures did not generally reduce CNG basal cover to low levels. None of the management options maintained reasonable levels of desirable perennial species by the end of 4-5years. We conclude that, because of the persistence of CNG, the need for regular spraying of herbicide, and the relative ineffectiveness of other control methods, management systems may need to be developed that utilize CNG while minimizing its input to the soil seedbank.