Climate variability - using water wisely

The earth's climate is constantly changing. Natural climate variability is a fact of life for Australian producers. It can mean vast differences in rainfall from one season to the next and differences in perceptions of 'normal rainfall' between generations.

Climate change will potentially impact specific agricultural industries in Australia and there are large regional differences in vulnerability. Some of the more broad-ranging threats include:

• increased risks to productivity due to more frequent and extreme weather events (floods, droughts and temperature extremes)
• decline in pasture quality and growth in some regions
• reduced stream flow and quality of water supply across southern Australia
• some crop yields benefiting from warmer conditions and higher carbon dioxide levels but vulnerable to reduced rainfall
• greater exposure of stock and crops to heat-related stress and disease
• southern migration of some pests
• likely increase in the distribution and abundance of some exotic weeds

Rainfall and water use

Water is the key to any successful agricultural enterprise and the health of our ecosystems. While we can’t control the amount of rainfall, we can actively manage what happens to that rain.

Effective management can increase annual ‘rainfall’ by up to 20%, by utilising rainfall more efficiently and effectively, increasing pasture production and potential productivity by up to 40%.

Producers have a responsibility to make productive and profitable use of rainfall. By doing so, they will not only achieve substantial increases in productivity, but also enhance and improve the environment, through less nutrient and fertiliser loss, reduced risk of soil erosion, soil acidity and dryland salinity.

In the context of managing pasture production and persistence in a more variable climate, red meat producers can increase water availability by:

• optimising the amount of rainfall that enters and is stored in the soil for maximised pasture use
• minimising the amount of rainfall that is lost from evaporation
• managing surface run-off at the soil surface by maintaining ground cover
• moderating the losses to deep drainage with deep-rooted perennials

To fully maximise the potential of rainfall in a grazing system, it is necessary to understand the water cycle - what happens to rain after it falls.