Farm grazing
Adding native perennial forage shrubs to the menu in mixed livestock and cropping systems can lift profits by up to 15–20%, while contributing to sustainable land management across southern Australia.
This has been a major finding of the Enrich project, which was set up in 2005, to examine a wide range of Australian native shrubs to use in grazing systems where other perennial options were limited.
Researchers tested more than 100 species, from a potential pool of 6,742 native woody flora, to develop a shortlist of 17, which comprises the most promising species to improve feed reliability, reduce salinity, erosion and greenhouse gases.
Enrich research sites in WA, SA and NSW found that incorporating a range of these species – with the exact mix depending on local conditions – into the feedbase has potential to increase sheep carrying capacity by 1DSE/ha during autumn, reduce autumn supplementary feeding costs by up to 60% from $13/ha to $5/ha and allow grazing of annual pastures to be deferred in the early winter months.
At a trial at Badgingarra, WA, sheep gained an average 100g/head/day on established forage shrubs and inter-row pastures and put on 0.5 of a condition score in six weeks in autumn.
SA Research and Development Institute (SARDI) Research Officer Jason Emms said, of the shrubs tested, about 25 had edible biomass of at least one third of old man saltbush and 52 had a rumen digestibility equal to or higher than oaten chaff.
The average crude protein level was 17% and all met minimum protein requirements to maintain liveweight in adult sheep.
“Many of these native perennial shrubs are high in mineral content and 15 species that we tested showed reduced methane production from sheep without reducing total gas production from fermentation,” he said.
“Twenty three species also reduced gastrointestinal parasite development compared to a control group.”
Enrich researchers have shown there is potential for a typical farm with forage shrubs covering an area of 7–9% to achieve a net carbon balance (sequestered carbon minus emissions) of about 230 tonnes of CO2-e/year and reduce groundwater recharge by an average 20% from 20ml/ha to 16ml/ha.
Economic modelling through Enrich, which was a collaboration between MLA through the Future Farm Industries CRC and led by CSIRO Livestock Industries, found planting 10% of a typical WA central wheatbelt property to native forage shrubs could lift whole farm profits by 15–20%, from about $102/ha to $117/ha.
The next phase of Enrich, from mid-2012 to late 2013, will analyse the animal performance and health, grazing management and environmental benefits of combining forage shrub species in a polyculture – where each plant is grown for a specific purpose.
Enrich research will culminate in a detailed producer information package due for release in late 2013 and facilitate the commercial availability of some shrub species.
Major findings of Enrich program 2005–12
•At least 17 shrub species identified as adapted and productive for low rainfall grazing systems
•Animal protein and grazing requirements can be met by shrubs
•Species need to be selected on their ability to persist and regrow after grazing
•Shrubs can fill summer and autumn feed gaps
•Shrubs could boost profit by up to 20% in marginal areas
•Shrubs can improve natural resource management
Native perennial forage shrubs suitable for grazing
Sandhill wattle (Acacia ligulata), Oleander wattle (Acacia neriifolia), River saltbush (Atriplex amnicola), Old man saltbush (Atriplex nummularia), River Murray saltbush (Atriplex rhagodioides), Tagasaste (Chamaecytisus prolifer), Nitre goosefoot (Chenopodium nitrariaceum), Tar bush (Eremophila glabra), Emu bush, (Eremophila longifolia), Ruby saltbush (Enchyleana tomentosa),Low pearl bluebush (Maireana astroticha), Small leaved bluebush (Maireana brevifolia), Black bluebush (Maireana pyramidata), Pearl bluebush (Maireana sedifolia), Tall saltbush (Rhagodia eremea), Mallee saltbush (Rhagodia preissii), and Thorny saltbush (Rhagodia spinescens)
Source: Argentine Beef Packers S.A.