Station managers at Austin Downs, near Cue in the Murchison region and Carey Downs in the Gascoyne region of Western Australia are running a project demonstrating different grazing intensities and resting periods and how they affect the survival of perennial ground-cover plants (PGP) through dry seasons.
The project is being delivered with the help of Greg Brennan of Grazing Innovation, supported by David Blood of Coodawa Contracting. They worked with Tom and Barbara Jackson, Martin King and Joanna Jackson-King at Austin Downs to establish trial sites in September. During December they are working with Harry and Alys McKeogh on Carey Downs.
Mr Brennan said the maintenance of perennial grass plants in many land systems of the Southern Rangeland systems is vital for sustainable livestock productivity and range condition.
“Also important are other ground cover plants including the Bindiis (Sclerolaena) and Sidas for sources of dietary energy to complement the protein of the shrubs,” he said.
“And there are lots of other valuable facultative perennials that will come along in the ‘slip stream’ if we manage for the persistence of grasses.”
Mr Brennan said the project aims to work with pastoralists to demonstrate practical, cost-effective livestock grazing management methods that will help ensure good survival of perennial grass plants, despite the inevitability of future dry seasons.
“Producers are linking grazing management that produces good ground cover with landscape function, livestock productivity and pastoral business profit,” he said
“Management practices are being redesigned to be practical, low cost and to optimise the probability of PGPs surviving dry seasons so that they continue to populate relevant land systems, build landscape function and incrementally improve productivity capacity each season.”
He said the challenge is to avoid the heavy grazing that often occurs through extended dry seasons and particularly when there is regrowth. Research, primarily with grasses, as well as practical experience, shows that heavy grazing of the perennial ground-cover plants (PGP) causes their death in dry seasons because it reduces their rooting depth and root volume. Reductions in rooting depth and volume means the plant cannot access sufficient reserves of soil moisture during dry seasons.
Aligned research shows that the PGPs, again particularly the grasses, regulate rainfall infiltration, overland water flow and livestock productivity.
“Finding ways to repopulate the landscape with PGPs may play a pivotal role in reinvigorating the pastoral industry of the region, which has been identified as a ‘high level strategy’ in the Mid-West Development Commission’s Blueprint.
Austin Downs was de-stocked of domestic animals in 2003 and cattle were re-introduced in small numbers in 2010.
“Since the de-stocking, the station has had good regeneration of ground cover, such that Tom Jackson has reported noticeably less run-off which is carrying much less sediment,” said Mr Brennan.
Good rainfall commenced in January 2015 and continued until June boosting the regeneration of perennial grasses, particularly on the Mileura, Cunya and Yanganoo land systems.
Mr Brennan said management at both Austin Downs and Carey Downs also incorporates Rangeland Self Herding principles that were introduced at various workshops by Bruce Maynard, Dean Revell and Fred Provenza, also funded by Rangelands NRM.
Mr Brennan, working with consultant David Blood, listened to the grazing management plans at Austin Downs and then negotiated how the project could be implemented to support their management decisions.
The grazing management at Austin Downs is currently a five paddock rotation with waters operating only where cattle are grazing.
“The five paddock rotation intensifies management, keeping costs down and enables more frequent handling of animals; but as Tom pointed out, they have to be ‘on the ball’ or it could amplify damage to the land and livestock performance,” said Mr Brennan.
“The plan is to return and re-do the monitoring sites next year after there has been sufficient rain to promote good pasture growth (at least 25mm of rain over three days, depending on conditions).”
“Then all will be revealed whether any of the treatments had a superior effect on the survival of the perennial ground-cover species. Of course, large differences after such a short period cannot be expected so funds have been sought from the National Landcare Programme to continue this work in future years at Austin Downs and to include two other stations."
For more information, contact Greg Brennan, Grazing Innovation, Geraldton.
Images courtesy of Greg Brennan:
1) Barbara and Tom Jackson with David Blood amongst Neverfail (Eragrostis setifolia) in Mileura land system.
2) Smaller root depth and volume of two heavily grazed plants near a water point reduces ability to stay alive through extended dry periods.