National approach to lift water use efficiency

With growers and researchers, the GRDC is embarking on a project that aims to lift water use efficiency by 10 per cent in five years

Researchers and grower groups from around Australia gathered in Canberra recently to kick-start one of the GRDC’s most ambitious national projects to date – that of increasing the water use efficiency (WUE) of Australia’s grain growers by 10 per cent in the next five years.
‘Increasing WUE in Australian Crops’ is a $17.6 million GRDC project involving 19 four-year research projects, 17 of which will be managed by regional grower groups and state agriculture departments in dryland and irrigated cropping systems dotted around the country. The remaining two projects will be managed by CSIRO and the South Australian Research and Development Institute (SARDI).
At a two-day meeting hosted by the GRDC to mark the initiative’s start, Stuart Kearns, GRDC manager for validation and adoption, said the aim of the meeting was to build a “team culture”.
“Everyone here has been chosen for their skills and project management capabilities and we want to start with an environment of working together,” he said, adding there were gains to be made when research built on existing knowledge.
Mr Kearns asked all researchers to start their projects by assessing the current WUEs of growers in their regions. “WUE is an indicator for adoption of more sustainable, efficient and profitable farming,” he said. Decisions by all stakeholders needed to be made early to identify what research areas would have the greatest impact on WUE – the “need-to-know versus the nice-to-know” information.
Both Mr Kearns and CSIRO senior principal research scientist Dr John Kirkegaard, who is overseeing the national CSIRO project, urged stakeholders to ensure their research did not focus only on the growing stage of the crop, but that equal attention was given to moisture management during the fallow and pasture phases of rotation.
“As we start the process, everybody needs to be on the same page,” Dr Kirkegaard said. “This will take patience as some projects are building on knowledge already established and others are starting with a blank page.”
James Hunt, a CSIRO research scientist employed to work on the WUE project, illustrated the importance of stored soil water with results reported for a 2008 National Variety Trial site. Mean site yield was reported as 3.6 tonnes a hectare when only 146 millimetres of growing-season rain (GSR) fell. Using WUE calculations it could be established that 1.9t/ha of the yield resulted from GSR and 1.7t/ha could be attributed to stored soil water.
Other research cited by Dr Hunt found that out-of-season rainfall made available to crops as stored soil water could account for about 0.4t/ha of grain yield, on average, in the Victorian Mallee, South Australia’s Upper Eyre Peninsula and the southern NSW growing regions.
“Storage of out-of-season rainfall varies greatly depending on soil type, rainfall patterns and weed control,” he said. Dr Hunt also urged researchers to consider the impact of rotations on carry-over water availability.
Presentations described current methods of soil water measurement, their levels of accuracy and the importance of characterising the water-holding capacity of the soil in establishing WUE for different regions.
Dr Hunt said he hoped one of the first important outcomes of all research projects would be to give growers more reliable methods of measuring stored soil water and predicting yield based on WUE knowledge.
Concurrent sessions outlining project objectives and initial outcomes for both high-rainfall and low-to-medium rainfall groups provided an opportunity to share experiences across environments with similar characteristics.
Research projects in the high-rainfall group focused on wheat and canola, the effects of waterlogging and disease management, and issues around stubble retention and row spacing trade-offs.
In the low-to-medium rainfall session the focus was equally distributed between in-crop management and summer fallow soil water storage, with specific projects giving value to weed management, rotations and when stored water was valuable for yield.
The initiative will hold similar annual meetings in different regions each year as a forum to share ideas, evaluate progress and discuss new technologies for improving WUE.

GRDC Research Code BWD00012
More information: James Hunt, 02 6246 5066, james.hunt@csiro.au

Back to the list of articles