Efforts to improve the management of dry/and salinity received a boost when a room full of Australia's top salinity scientists recently brainstormed the 'state of play' and future needs for salinity research. Cathy Nicoll reports.
RESEARCHERS CAN now provide a range of options to help growers manage dryland salinity and more strategies are on the horizon. That's the take-home message from the recent GRDC-sponsored workshop on 'Managing Water to Improve Productivity and Control Dryland Salinity'.
The workshop drew together more than 50 scientists involved in soils, crops, pastures and groundwater systems research.
Participants agreed that the management options growers can implement are generally specific to each location and farm, but the following provide some general guidelines.
- Farming systems based on annual crops and pastures generally won't control dryland salinity. The exceptions to this may be places where rainfall and evapo-transpiration are roughly matched, and places where double or opportunity cropping is possible in the northern grains zone. Annual systems have typically contributed to the spread of waterlogging and dryland salinity.
- Trees, lucerne or other perennial crops and pastures can work in smaller catchments where groundwater systems are local and will respond to increased water use in the relatively short time of a few years to decades.
- In regional groundwater systems, such as on extensive riverine plains, it is unlikely that any plant species will ever use enough water to control dryland salinity during our lifetime. For this reason, engineering options that focus on managing water, such as shallow and deep drains, raised beds, and groundwater pumps and wells, must be used.
- Strategies that allow growers to make some productive use of saline discharge sites serve to maintain cover and productivity and they can form part of the overall package.
- In most areas a combination of the above strategies will be required.
The choice of engineering or plant options will depend upon many factors, not least of which are the preferences of individual growers, how the option fits in with their cropping systems, and its profitability. It is unlikely that a single solution will work in any catchment in Australia.
"The number of well-studied options that we now have is a huge step forward from even 10 years ago when researchers were more likely to hedge their bets and ask for more time to study data and results," said workshop convenor, Phil Price.
He said the workshop again emphasised the amount of water that is not used by annual crops and pastures and is then moving below the rooting zone of cropping systems. "This is basically a wasted resource that could have been used for profit, thereby also reducing recharge."
The big remaining gap, according to Dr Price, lies between the tools that are known to researchers and those that are available to growers in making day-to-day farm management decisions. "We now need to test and refine these predictive tools, and the on-farm management options, with groups of graingrowers."
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