Native pastures
Landholders are encouraged to implement good grazing management practices to help maintain their pasture species mix and groundcover levels.
Allowing pastures to set seed periodically is important in maintaining the seedbed for desirable native pasture species.
It is particularly important to have this native seedbed of palatable species available for drier years where there may not be a good pasture germination.
Monitoring native pasture composition
Some native shrubs and grasses require monitoring to ensure they do not become invasive and dominate native grasses.
For areas of bare ground where potentially problematic shrubs are not producing dense cover, it may be possible to wait until spring or summer before doing anything and allowing natural regeneration of native pastures to occur.
Where there is sunlight to the soil surface then native pastures should be able to germinate and persist. The key is to allow these pastures to persist and dominate – they will out compete potentially problematic native shrubs through shading and use of moisture.
For stands of native shrub that have been persistent for some time, and where grazing management and/or seasonal conditions have not resulted in a reduction in coverage, other management options should be explored.
Control options
Mechanical cultivation is one potential option for controlling the spread of less desirable native pasture species.
Seedlings are unlikely to establish from seed buried to a depth of 40 mm or more. Ploughing arable areas with an implement that inverts the soil will reduce the size of the viable seed bank in heavily infested areas.
It is important to note, that this level of disturbance is likely to require approval under the Land Management (Native Vegetation) Code 2018.
Native pasture species to watch for
Some native species present mustering challenges, may be less productive than a more diverse native pasture, or have a tendency to spread.
Goathead burr
Goathead burr (Sclerolaena bicornis) is a perennial shrub native to inland Australia. It is a complex branched shrub, growing up to 50cm in height. The branches are white and woolly with widely spaced slender leaves. The fruits can be distinguished from other burrs by the two horned appearance with two long spines, with one of the two varieties having a slightly smaller fruiting body (burr) with shorter spines.
Plants often appear in spring as the soil warms and in late summer will produce the sharp seed head however, the species is known to germinate and grow at other times of year depending on rainfall and seasonal conditions.
Goathead burr has a widespread distribution. It is more common in areas that have seen intensive historic grazing practices. Native pasture monitoring records show that the relative percentage biomass of species such as goathead burr can fluctuate over time, with influencing factors such as soil and landscape characteristics, seasonal conditions and livestock grazing history resulting in periods where goathead burr grows densely, but then thins out.
Benefits of goathead burr
Goathead burr can be a valuable feedsource. It is palatable to livestock and can, at certain growth stages contain a reasonable level of nutrition for animal production. It is not recommended that it be the only feed source available to the animals.
In addition to feed value, the groundcover it provides can also have value, such as during drought.
Problems with goathead burr
Goathead burr has become more prominent in recent years, particularly post drought, and has in certain areas of Western NSW has become the most prevalent plant species present in the native pastures.
Goathead burr is often one of the first plants to germinate and grow following on from rainfall events. Adequate rainfall in winter can result in high germination rates of burrs, when this is followed by rainfall in spring or early summer, dense stands of burr may result. The goathead burr seeds are also slower to break down then other species – given their hardness, leading to large numbers of viable seeds in the seedbank.