University of Melbourne / Victorian DPI
The University of Melbourne (UoM) (often in conjunction with TIA) conducted modelling activities to address a range of key industry questions on climate change impacts, adaptation and mitigation for the southern Australian grazing industries. The project utilised a network of credible ‘base’ simulations for over 20 sites across southern Australia. The sites spanned a range of climates in southern Australia from high rainfall, cool temperate in Tasmania to lower rainfall, temperate environments of southern New South Wales, through to Mediterranean climates in Western Australia and sub-tropical climates in south eastern Queensland.
This section provides an overview of that research and provides directions for more information
Significant additional modelling capability and capacity was developed during this project, with both DairyMod and SGS models enhanced to include a more sophisticated animal model, improved soil organic carbon modules, and the explicit treatment of urine patch dynamics. These have all enhanced the models capacity to predict methane, nitrous oxide, soil carbon and the interactions between these. The team also developed the Carbon Offset Scenarios Tool (COST) to explore the viability of a range of mitigation options that could be included as Carbon Farming Initiative (CFI) offsets.
Total annual pasture production in southern Australia is generally resilient to climate changes of +1° with 10% less rainfall, but further changes are likely to reduce annual pasture growth. View a summary of the research.
View a range of pasture response curves under varying temperature and rainfall scenarios for different locations
- Warmer and drier future climates projected for southern Australia will change the seasonal pattern of pasture growth, with higher pasture growth rates in winter and early spring but a contraction of the spring growing season, with an earlier onset of the dry summer period. View a summary of the research.
View more information on seasonal pattern of pasture growth
- Deep rooting and heat tolerant traits will be important adaptations for pasture species in future warmer and drier climates. View a summary of the research.
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In regions where C4 grasses are not currently grown, substantial warming is still required before C4 grasses will be more productive than the current C3 species. View details on this research.
View more information on C3 versus C4 grasses.
Analysis of historical climate at five sites across Victoria and Tasmania indicates a trend for a greater frequency of short spring growing seasons across sites, but no clear trend of increasing variability in pasture production. View a summary of the research.
View more information on shorter springs.
- A comparison of whole farm GHG emissions from different farm types in south eastern Australia showed dairy farms producing the highest emissions/ha, followed by beef, sheep and grains. View a summary of the research.
- When compared on an emissions intensity basis, cow/calf farms emitted more GHG/unit product than wool, followed by prime lamb, dairy, steers and finally grains. View a summary of the research.
- One hundred Australian dairy farms were assessed for their GHG emissions with the mean intensity of 1.04 kg CO2e/kg milk, although individual farms varied between 0.76 and 1.68 kg CO2e/kg milk. View a summary of the research.
- Whole system mitigation modelling showed that the emissions intensity per unit product can be minimised simply by maintaining a productive pasture base. View a summary of the research.
- Inclusion of residual feed intake in national breeding schemes should reduce emissions intensity of ruminant production systems, over and above on-going reductions in emission intensity being achieved by the current production and fitness trait breeding goals used. View a summary of the research.
- Modelling of dung and urine distribution showed that the non-uniform distribution of excreta significantly influences the annual nitrogen losses through leaching and denitrification from a grazing system. When modelling N2O emissions from grazing systems it is imperative therefore that dung and urine distribution be explicitly modelled and not assumed to be evenly spread across the pasture. View a summary of the research.
- While methane emissions will mainly change with livestock numbers, nitrous oxide emissions may increase with warmer climatic conditions in the medium-high rainfall zone of southern Australia, particularly in less free draining soils. This emphasises that mitigation modelling must include consideration of adaptation and vice versa. View a summary of the research.
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View other findings coming from this research see also the Primary Industries Climate Challenge Centre.
View a summary of the UoM key findings.