Adapting SA dairy farms to climate change
On-Farm Adaptation Strategies
The impacts of a changing and more variable climate on dairy farming will require a range of on-farm strategies and solutions. This section identifies both positive and negative effects of climate change and suggests possible adaptation strategies for dairy farmers.
Positive impacts and management responses to a changing climate:
- Increased pasture growth during longer and warmer winter months, and increased carbon dioxide in the atmosphere will boost plant photosynthesis rates and hence total dry matter production. Possible management options include:
- Sow pastures earlier to match warmer conditions. For example, if you currently sow pastures in mid May, this could be brought forward to early May.
- Apply fertiliser in winter and early spring. Under warmer winter conditions, plants will be able to utilise fertiliser to achieve winter growth and the spring flush is likely to be earlier, hence applying fertiliser earlier will promote earlier growth.
- Grow and utilise more pasture during warmer ‘cold’ months. The opportunity to grow more pasture during winter months will enable greater pasture utilisation.
- Sow and harvest summer crops earlier. Warmer spring and hotter summer conditions will enable cropping to be brought forward, to make best use of earlier warm conditions and to avoid the peak heat of summer.
- Lower water availability will favour short rotation pasture systems. Warmer spring and hotter summer conditions.
- Increase intensity of short rotation systems to combat lower water availability.
- Cut silage and hay 2-3 weeks earlier to better match the changing pasture growth curve.
- Sow and harvest summer crops earlier. Warmer spring and hotter summer conditions will enable cropping to be brought forward, to make use of earlier warmer conditions and to avoid the peak heat of summer.
- Investigate shifting from perennial pastures to a mix of annual and perennial pastures.
- Use drought tolerant perennial pasture species to capitalise on the longer growing period. Increased temperatures during spring and summer, and increased likelihood of drought conditions will suit more drought tolerant pasture species.
Negative impacts and management responses to a changing climate
- Warmer spring and hotter summer temperatures may increase the incidence of heat stress in cows. Heat stress can negatively impact on milk production, fertility and weight gain. Pasture production and quality may be compromised by hotter and drier spring and summer conditions. Possible management options include:
- Establish &/or extend shade and shelter belts to reduce the impacts of increased temperatures and more days of extreme heat.
- Provide evaporative cooling for cows where appropriate. Increased average temperatures and higher temperature spikes will create the need to cool cows more often.
- Selectively breed for improved cow performance during hot weather. Higher average temperatures mean that more heat tolerant cattle will be desirable.
- Adjust mating and reproductive strategies to take into account:
- changes in pasture availability
- reduced fertility of cows as a result of higher temperatures
- less efficient milk production during heat waves
- Consider the best possible pasture species mixes, that will:
- tolerate hotter summers
- have maturity times adapted to earlier spring conditions.
- Increased temperatures may make C4 pasture species (such as kikuyu, maize, forage sorghum) more competitive at the expense of the more nutritious C3 species (such as ryegrasses).
- Increased moisture evaporation rates, reduced run-off, and increased frequency of drought due to increased temperatures and reduced soil moisture. Possible management options include:
- Improving irrigation water use efficiency through increased use automation and irrigation scheduling.
- Reviewing the feedbase to make best possible use of water when it is available, this may involve changing the annual/perennial mix and forage base.
- Improving on-farm water capture/harvest methods where ever possible. More variable rainfall may result in heavier rainfall that may overload existing methods of water harvesting.
- Increasing on-farm water storage capacity where ever possible. More variable rainfall may result in heavier rainfall that may overload existing methods of water harvesting.
- Placing a greater emphasis on:
- improving the efficiency of irrigation systems and practices
- expanding use of dairy shed effluent and wash down water
- improving the management of bores for water supply
- planning the shape of dams to maximise the capture of run-off
- planting trees near dams to reduce evaporation
- Consider increasing forage cropping to produce maximum dry matter per mega litre of water used.
- There may be impacts on both the quality and quantity of feed grains and fodder produced outside dairy areas. For example, legume hay may be less readily available and more expensive. Possible management options include:
- Adjusting the approach to feed management and purchases to take into account increased climate variability. Farming systems that rely heavily on buying in feed may need to secure supplies 6-24 months in advance, while those that grow all their own feed may need to cut more silage and hay to manage the risk of less predictable seasons.
- Consider forward contracts for purchasing grain, hay and concentrates.
- Refer to Dairy Australia’s Grains2Milk program plus the weekly Grain & Hay Report – both are available on the main DA website.
- Short-term and seasonal forecasts may become (even) less reliable due to increased climate variability.
- Greater uncertainty within seasons means farmers should be prepared for anything, including extreme conditions. Plan ahead with extreme events in mind.
- Be familiar with and consider appropriate insurance options.
For more information on seasonal forecasts, visit the Bureau of Meteorology Water and The Land site.