Tasmanian pasture resource audit: Snapshot of functional group composition in 2011

There is widespread concern from agronomists and industry experts regarding the productivity and quality of improved pastures in Tasmania. At the same time, there is interest from the State Government and industry stakeholders on the potential to increase productivity by improving botanical composition. A study was conducted in 2011 to provide a snapshot of the botanical composition of improved pastures across the state. We surveyed 846 pastures along 116 roadside transects across 20 of Tasmania’s 29 Local Government Areas (LGAs). Individual pastures were assessed on the basis of percentage cover for each species. On a survey-wide basis, desirable sown perennial grasses made up just 33% of the pasture cover and this varied significantly between LGAs, while the cover of perennial legumes was 7%. Desirable sown perennial grasses were most dominant in the higher rainfall LGAs in pastures used for dairy and intensive beef production. Perennial ryegrass, cocksfoot and white clover were the most common desirable species alongside weedy perennial grasses. In contrast, desirable perennial species were lowest in the low rainfall LGAs. Weedy grasses were the most prevalent non-desirable species in pastures and combined for 3% of the composition. Weedy annual grasses were most prevalent in LGAs characterised by low rainfall and extensive sheep grazing for wool production, while weedy perennial grasses were most abundant in the medium-high rainfall LGAs in pastures used for a range of grazing enterprises. Increasing the content of perennial pasture species in all regions, but particularly the low-medium rainfall regions should remain a priority for research and extension projects. There is also considerable potential to increase the area and use of lucerne as an alternative feed supply in the extensive grazing regions of Tasmania.