Whole Farm Systems Analysis of Climate Change Impacts on the Southern Grazing Industries (University of Melbourne component)- (a sub-project under the Climate Change Adaptation in the Southern Aust…

Summary

Modelling activities were undertaken to investigate a range of key questions on climate change impacts, mitigation, and adaptation measures for the southern Australian grazing industries as part of the Southern Livestock Adaptation 2030 (SLA 2030) program. Numerous simulations were conducted, resulting in over 15 peer reviewed papers, one book chapter and 15 conference papers.

The Carbon Offset Scenarios Tool (COST) was developed to explore the viability of a range of mitigation options that could be included as Carbon Farming Initiative (CFI) offsets. A comparison of whole farm greenhouse gas emissions from different farm types in south eastern Australia showed dairy farms producing the highest emissions per hectare, followed by beef, sheep and grains.

Whole system mitigation modelling showed that the emissions intensity per unit product can be minimised simply by maintaining a productive pasture base.

Objectives

The objectives of this project were to develop:

• biophysical modelling simulations that address the key regional questions of climate change impacts (short and long-term) on current grazing systems in a future environment, adaptation options and new farming systems
• a distributed climate impacts and mitigation modelling capability in the Australian grazing industries
• a better informed industry and producer population of the opportunities and risks associated with climate change through the publication and communication of research results.

Key findings

• Numerous simulations were conducted, resulting in over 15 peer reviewed papers, one book chapter and 15 conference papers from the team.
• The project team also developed the Carbon Offset Scenarios Tool (COST) to explore the viability of a range of mitiga
• tion options that could be included as Carbon Farming Initiative (CFI) offsets. 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.
• Whole system mitigation modelling showed that the emissions intensity per unit product can be minimised simply by maintaining a productive pasture base.

Benefits to industry

Significant additional modelling capability and capacity was developed. The DairyMod and SGS models were expanded with 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 project team provided training to over 50 scientists, consultants and extension officers, and six postgraduate students, representing a significant capability boost for industry.

Future 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.