Primary Production Landscapes Home | Southern Plains Home
Covering 51 local government areas and 6 catchment management authority regions, the major land use of the Southern Plains is production from dryland agriculture cropping, grazing and dairy) and forestry (77%). New blue gum forestry plantings are estimated to be 10,000 – 14,000 hectares per year. This has moderated since 8-10 years ago. Irrigated agriculture (8%) and intensive uses including horticulture and animal production (36% of Victoria’s land use) occur also. Rainfall varies from 450 mm west of Melbourne to 1100 mm at the foothills of the Southern Uplands.
|Primary Production Landscapes
Victorian Volcanic Plains
Volcanic cones, lava flows and ash deposits are used mainly for grazing and cropping. Rainfall is higher and evaporation less than plains north of the divide.
Dundas & Merino Tablelands
The deeply dissected and weathered terrain has traditionally been used for grazing. Constraints to plant growth include soils with low pH and iron gravels that limit access to soil moisture.
Rainfall within the plains is quite variable and the terrain diverse. Waterlogging is a major production constraint for prominent land uses including dairy and forestry.
Siliceous and calcareous plains and dunes are mainly used for dairy, forestry and fodder production. Soils and landforms continue into South Australia where viticulture also occurs.
Extensive alluvial systems from erosion of the Eastern Uplands generally receive higher rainfall and less evaporation than plains in the west. Grazing, forestry and dairy are main land uses on gradational and texture contrast soils.
|Management practices and issues in response to Climate Change
- Blue gum growth cycle is 10-12 years (expected to be 10-15 years in the future in response to climate change). Pine forestry has a 30 year rotation with 3 thinnings for commercial purposes.
- Site selection criteria for planting have been relaxed with time (different criteria used by different companies).
- Impacts of land use change from grazing to blue gums include increasing regional land prices. Land prices were cheap. This has changed in response to dairy, grain and forestry competition.
- Attraction to the industry is return on commodities to investors (tax arrangements) and carbon credits.
- Demographics have altered across regional areas with many existing farms having no succession plan.
- Climate change impacts include:
- There are current forestry sites that won’t be planted again (marginal rainfall areas).
- Blue gum thinning occurs to reduce competition for moisture (native forests are impacted also).
- Blue gum production rates have decreased (these growth fluctuations can be hidden in the life cycle of plantations).
- Less scope or ability to adjust to stresses than other farming systems.
- Production test will come at the end of first plantation harvest (expected to begin in 12-24 months).
- Water issues including groundwater supply and reduced surface runoff from plantations are still being understood.
- Biodiversity within plantations is better than expected.
Future scenarios for farming systems
Victoria’s changing climate
Mean annual temperature (two scenarios from past records and one predicted scenario)
- Experiences in growth rates and selection criteria will likely see changes in selection criteria to suit climate change. Drier seasons may also pose an increased fire threat to plantations.
- Currently nearing the end of the plantation establishment phase. There will be a move to harvest and rate of expansion unlikely to continue. Carbon trading is an unknown factor here.
- Will price fluctuations in wood and competition from other grain and dairy industries increase pressure on forestry in higher rainfall landscapes?
- Logistical issues including transport infrastructure and mills for processing an expected 3.5 M tonnes of wood in the next decade be addressed?
- Workforce shortages for harvesting are also a major issue.
- Global demand for wood and pulp is not decreasing though price fluctuations in the market is an issue.
- Significant lack of investment in non-commercial species for water conservation approaches. This includes work on hybrids with low rainfall genetics and seed breeding trials.
2050 A1FI prediction
2050 A1FI prediction