Cathy Reade creade at squirrel.com.au
Tue Aug 15 12:28:24 CEST 2006

16 August 2006


The increasing demand for global irrigation is placing pressure on water
supplies, particularly where supplies are already inadequate. Yet irrigated
agriculture is needed to feed the world’s growing population. Improved water
productivity is essential for future irrigated production and supply of
quality food and amenities.  “But how much improvement is possible?” asks Dr
Wayne Meyer, Chief Scientist for the Cooperative Research Centre for
Irrigation Futures (CRC IF).

The answer to this question is being explored today (16 August) at the
Crawford Fund’s international development conference: “Water for Irrigated
Agriculture: Finding a Flow For All” at Canberra’s Parliament House.

(The event will be opened by The Hon Alexander Downer, Minister for Foreign
Affairs (9am) followed by a keynote address by Dr Frank Rijsberman, Director
General of the International Water Management Institute, the worlds
pre-eminent research institution on management of water for food and
agriculture.  A press conference will be held at 12pm in the Theatrette. The
Hon. Malcolm Turnbull will address the future of Australia’s water policy at
3.35pm. Other international and national specialists will cover issues such
as future water availability; climate change; and lessons and problems in
regions of China, the Mekong Delta, the Indo-Gangetic Basin and Australia’s

More than one third of the world's food is produced on about 250 million
hectares of irrigated land that accounts for about 80% of global fresh water
consumption. The last decade has seen a disjuncture between increasing world
population and area of irrigated land; new irrigation development has slowed
and population growth continues unabated.

“The connection between irrigated production and the supply of food is
increasingly dependant on improved productivity rather than increased area,”
says Dr Meyer.

“Add to this the increased demand from urban and industrial use and for
ecosystem maintenance and the pressure is on for increased irrigated
agricultural productivity.”

Irrigation is an energy intensive activity that requires a systematic
analysis if potential improvements are to be identified. Dr Meyer’s
discussion considers opportunities and limitations to improvement from
plants through to catchments, from both production and natural resource use

“When we analyse the use of water in irrigation the first thing that is
immediately obvious is that there is tremendous variability in the
efficiency of use between regions, between different commodity production
systems and between different managers.  There are often good reasons for
these differences, but as with any business every effort should be made to
improve the use of resources and improve productivity,” asserts Dr Meyer.

“A major way we have improved water use productivity over the last few
decades is through increased yields with better varieties and better
agronomy.  Within a plant species, however, the intrinsic relation between
dry matter accumulation and water transpired seems to be at its genetic
limit, hence there is little gain to be made.”

However, according to Dr Meyer, water productivity with crops can still be
significantly improved by using irrigation systems and agronomic practices
that minimise the loss of water through soil evaporation and deep drainage.

“Many of our distribution systems also have unacceptable losses through
seepage, and with a current emphasis on measuring and improved control
structures, significant improvements that reduce unproductive water losses
are possible,” he says.

“The major limitation in applying these systems and practices is financial –
in many cases there is simply insufficient return to justify the large
capital and operating costs for more controlled systems.”

There continues to be a major emphasis on increasing water use efficiency.
However the relationship between plant water use and yield is such that
maximum water use efficiency occurs when plants are fully supplied with

“In Australia, with its variable rainfall and water supply, many pasture and
grain crops are not fully irrigated. This makes financial and management
sense in terms of the farm business.  We should therefore be cautious not to
blindly pursue maximum water use efficiency as an end goal – rather we
should take a more encompassing view of increasing water use productivity,”
Dr Meyer says.

He explains that such productivity not only includes yield and financial
returns but also community and environmental productivity.  Currently there
is insufficient water to satisfy all production, environmental and amenity
needs so finding the best compromises is the major challenge.

“It’s about increasing multi-purpose water use productivity - a significant
component of which is improving the productivity of the total irrigation
system.  The analysis indicates that achieving a doubling of yield at a crop
level will be hard, but halving the water used is possible but expensive,”
states Dr Meyer.

Further information, photos, additional press releases, abstracts and bios
are available at www.crawfordfund.org or by contacting Cathy Reade, Public
Awareness Coordinator, Crawford Fund on 0413 575 934.

The ATSE Crawford Fund wishes to thanks the sponsors for this event,
Alliance of the CGIAR Centers; AusAID - the Australian Agency for
International Development; Australian Centre for International Agricultural
Research; Australian Government Department of Agriculture, Fisheries and
Forestry; Australian Government Department of the Environment and Heritage;
CRC for Irrigation Futures; CSIRO Land and Water; CSIRO Livestock
Industries; Grains Research and Development Corporation; International Water
Management Institute; Land & Water Australia; Murray-Darling Basin
Commission; National Water Commission
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