Native and naturalised pastures
Detailed descriptions of the region’s grassland as they appeared to the first settlers do not exist, but tall summer growing perennial grasses probably dominated, similar to that found on the northern slopes and tablelands (Lodge & Whalley 1989). The dominant species was probably kangaroo grass (Themeda australis) with subsidiary grasses such as red grass (Bothriochloa macra), wiregrass (Aristida ramosa), bluegrass (Dicanthium sericeum), wallaby grass (Danthonia spp) and weeping grass (Microleanna stipoides).
Native and naturalised species still comprise about 70% of the grasslands in the Hunter region areas. They are consequently a major determinant of potential grazing options and capacity, particularly in steeper and less well developed areas.
Most native pastures are complex plant communities that contain a large number of species with varying drought tolerance, feed values and persistence when grazed. Up to 100 different plant species often occur in a single paddock. However, 5 to 20 common grasses usually dominate and determine the overall productive potential.
The dominant species within native pastures, however, can change from season to season and even from year to year depending on; rainfall, temperature, fertiliser application and grazing management. Native and naturalised grasses also vary widely in their forage value, acceptability to stock and ability to produce feed.
Native grasses with the highest grazing value are typically those that retain green leaf for most of the year such as Wallaby grass (Danthonia spp) (also known as white-top) or weeping grass (Microleanna stipoides). Other native grasses provide useful feed during their narrow growing season. Summer growing perennial grasses such as kangaroo grass (Themeda australis) produces reasonable spring and early summer feed.
Local native grasses of least grazing value include; wiregrass (Aristida ramosa), blady grass (Imperata cylindrica) and barbwire grass (Cymbopogon refractus). These species are composed mainly of coarse stems or leaves that are unpalatable and indigestible. Pastures considered as ‘native’ often also include introduced species that also have low palatability or feed value, such as carpet grass (Axonopus affinis), which is now widespread in the region.
Most native pastures are drought resistant and do not require fertiliser to survive on poorer soils. Species diversity within native pastures can also provide adaptability to climatic variability and grazing, hence they can be useful for erosion control and biodiversity. However, native pastures in the Hunter region usually support low stocking rates and will rarely fatten growing stock.
The biggest limitation is their poor feed quality and lack of growth during the winter. When reliant on native pastures, cattle commonly stop growing or even lose weight during the cooler months.
Legumes, especially subterranean clover (Trifolium subterranean) or white clover (Trifolium repens) are often sown into native pastures to increase winter pasture growth. Applying a sulfur and phosphorus fertiliser (eg. single superphosphate) with the inoculated legume seed further increases pasture production and quality. This allows more consistent growth and improves cattle fertility and calving success. The diversity of native pastures can also be retained or increased with appropriate management.
Stocking rates need adjusting to use the additional productivity effectively. A more profitable type of beef enterprises may also become suitable. Further information on managing native pastures is available from DPI publications.
