Summary

Two separate experiments on the North-West Slopes of New South Wales investigated: (1) the effects of differing lengths of pre-sowing weed control (2 years, 1-year and 3-4 months in the spring immediately prior to sowing) on the seed density of liverseed grass (November 2005 to November 2007) and its seedling density at establishment (December 2007), as well as subsequent herbage mass and plant frequency of this species and cv. Bambatsi (Experiment 1), and (2) the effects of cultivar, time of sowing (November 2006, January 2007 and March 2007) and defoliation in the autumn after sowing, on the over-wintering ability of 5 tropical perennial grasses (Experiment 2).

At sowing (November 2007), liverseed grass seed and seedling densities in Experiment 1 were lowest in the 2-year pre-sowing weed control treatment (15 and 13/m2, respectively) and the subsequent herbage mass of Bambatsi (January and October 2008) was highest in this treatment. In Experiment 2, 59 frosts occurred in 2007 and Floren, Bambatsi and Swann sown in March of that year, over-wintered poorly and had lower herbage mass and plant frequency in the following spring compared with the other sowing times. These differences were also evident in autumn and spring 2008, up to 23 months after sowing.