Native plants boost grazing options
An innovative pastures project is testing native shrubs for use in mixed-forage systems designed to better withstand Australia's dry climate
In the hard-hit northern sheep/wheatbelt of Western Australia, as crops and pasture failed in the spring of 2006, growers near Binnu, 100 kilometres north of Geraldton, witnessed a native perennial shrub survive and provide palatable feed for sheep while other food sources dried up.
The saltbush-like shrub called Rhagodia not only remained green without rain, it could be established during prolonged periods of low rainfall.
"All the farmers that sowed test plantations of two or three hectares are saying they wish they had more," says Tim Wiley, the Geraldton-based development officer for the Department of Agriculture and Food, Western Australia (DAFWA). "They see the shrub as a way to drought-proof their farms."
Based on the WA experience, Rhagodia (pictured right, photo: Tim Wiley) was recommended for inclusion in the Enrich Project, a national R&D effort to use native plants to construct uniquely Australian mixed-forage systems based on the resilience of native shrub species.
"We are not trying to recreate native bush, but rather use it as a template for forage systems that can remain green year-round and tolerate conditions that challenge more traditional annual pastures and crops," says Dr Dean Revell, the CSIRO Livestock Industries senior scientist who is leading the project.
"However, the ability to provide valuable feed in dry seasons is not the sole benefit of these forage shrubs. According to some recent economic modelling, forage shrubs on a modest area of the farm are capable of improving whole-farm profitability in average years, besides reducing risk due to seasonal variation."
Benefits to farmers are being maximised by deliberately designing plant mixtures that can deliver animal health and improved land-management outcomes, which in turn help lower input costs.
On the downside, Dr Revell (pictured right examining saltbush, photo: Evan Collis) says people tend to associate diverse plant mixtures with greater management complexity.
"The concept of mixed pastures is well understood so the task of Enrich is to solve the obstacles to implementation. We need to know which species to plant, in what combinations, where on the farm and how to graze them."
Under the umbrella of Enrich, parallel research activities are under way that collectively could deliver mixed forages to the southern livestock-cropping zone. Researchers are all linked through the Cooperative Research Centre for Plant-based Management of Dryland Salinity (CRC Salinity) and are based at CSIRO Livestock Industries, the University of Western Australia, DAFWA, SARDI, the NSW Department of Primary Industries and the South Australian Department of Water, Land and Biodiversity Conservation.
Over three years, the researchers are looking to:
- propagate and test under field conditions the forage potential of about 100 native shrub species at a research site in Monarto in SA;
- measure the shrubs' nutritional value;
- test the same plant material for bioactive compounds that can affect rumen health and control gut parasites;
- establish a field site at Badgingarra, WA, with six shrub species and some perennial grasses that can be further sown with annual pasture species in the 2007 season to provide a test grazing site to look at grazing behaviour and ways to modify it;
- complete face-to-face surveys with farmers in WA, SA, Victoria and NSW who have experience with shrubs; and
- perform economic modelling using different establishment costs and different productivity levels to help understand the factors that can optimise whole-farm profitability.
Crucial to the shift away from monoculture is the idea that growers can use livestock directly to help manage the extra complexity. This can seem like a ‘wacky' idea, but Dr Revell has visited the US where it is already being successfully put into practice.
"Animals can be better than us at making informed decisions about what to eat and when to eat it," he says. "We've done our best to supposedly simplify systems and pastures, but there is a lot of exciting research worldwide saying animals can manage decisions about different plant species that are complementary for nutritional and health values, particularly gut and rumen health, even reduced worm parasite loads."
The trick is to provide livestock with the right experiences of all of the plants in the mixture and then rely on their learnt grazing behaviour.
As to the polycultures themselves, they stand to offer greater flexibility and resilience to a farm by strengthening the ability to respond to environmental and economic pressure.
"Australia's rural landscape can pose tough challenges for farmers even at the best of times but many current problems – like dryland salinity, susceptibility to drought, and soil erosion – stem from the replacement of native perennial vegetation with annual crops and pastures," Dr Revell says. "This means that perennial forage systems offer prospects for managing many of these issues and Enrich is about gaining the experience growers need to benefit from a perennial feedbase."
The Enrich Project will run until June 2008 with researchers hoping to host field days as early as 2007 at the SA and WA sites. The project is funded by AWI, Meat and Livestock Australia, the Rural Industries Research and Development Corporation and the CRC Salinity.
More information: Pasture information or contact Dr Dean Revell, dean.revell@csiro.au
Return to Beyond the Bale Issue 26 index page.