Less irrigation raises question of environmental effects

Environmental assessment normally is associated with expansion but, as irrigators in the Riverina have found, the effects of less water are also of interest.

Funding was made available through the National Program for Sustainable Irrigation last year as part of a three year research program to quantify the effects of changing irrigation strategies on biodiversity in the region.

Undertaking the work are CSIRO Sustainable Ecosystems researchers Heather McGinness, Tony Arthur and Sue McIntyre.

As Heather McGinness explains, changes to the amount, quality and timing of irrigation can disrupt flora and fauna that has previously benefited from earlier irrigation practices.

“These practices have provided large amounts of free water with irrigation channels, impoundments and flooded crop growing areas becoming habitats which a variety of species use as sources of food and water,” she said.

The study is investigating likely changes to irrigation practices and patterns of water use in an increasingly hot and dry environment. It has included a literature review of biodiversity in the Riverina so that a good picture can be provided of natural and managed ecosystems, and continuing research interests include local and regional implications of changed irrigation practices for biodiversity persistence.

Although the study will continue until late 2011, there is sufficient knowledge available for CSIRO Sustainable Ecosystems to recommend that remaining native vegetation be protected and that land use planning consider its health. A feature of the region, for example, is the black box woodlands which can benefit significantly from environmental watering and reduced disturbance.

A bonus for the research team has been the existence of environment-conscious ricegrowers who for many years have not only improved their water use efficiency by 60% since 1998 but have also voluntarily worked together to preserve tracts of black box and other native vegetation. The effort was formalised in 2000 with formation of the Environmental Champions Program to promote environmental stewardship. Members now contribute to the project funded by the National Program for Sustainable Irrigation, providing study sites and information to the CSIRO researchers.

Manager of environmental programs with the Ricegrowers’ Association of Australia, Janelle McGufficke, says that while ricegrowers have suffered from extremely low water allocations they have continued their interest in the environment. Apart from the effect on returns the lower production has meant production-based levies for research have been affected. It is therefore heartening that at least some research continues into getting the best from every drop of available water, while other research is looking at what water scarcity may mean for the environment.

“Our Environmental Champions Program is about practice improvement and adoption of an environmental management system,” she said.

“It starts with basic industry standards, including an irrigation skills component, progressing to whole of farm planning and working in partnerships to address regional and catchment level issues. Interests range from sharing practical solutions to problems on the farm to understanding how to reduce greenhouse emissions.”

Leeton ricegrower Peter Draper believes that by world standards Australian ricegrowers stand tall with regard to biodiversity and sustainability, using a rotational rather than monoculture system and applying about a fifth of the water that other ricegrowing countries use to produce a tonne of rice. Australia’s rotational system has the advantage of providing extra production, where rice may be followed by sowings of oats, canola, wheat, barley, canola or livestock, with the capacity of grain crops to draw on residual moisture.

“All this adds up to production efficiency as well as having regard for the environment,” he said.

“Our system means we don’t have the persistence of insect pests and diseases that monocultures invite in most other parts of the world, a result of which is far higher use of chemicals.”

Relatively low inputs for crop protection, he considers, mean a healthy environment and biodiversity strength. There has also been protection of remnant vegetation by Peter Draper and others to provide habitat and corridors for resident species. On his own property he has seen the endangered Australian bittern, a long list of native birds and visitors like sandpipers and the Japanese snipe.

“When you grow rice you see things come to life, from insects and frogs to small and large water birds,” he said. “We see the whole food chain.”

More information

The effect of changing irrigation strategies on biodiversity project.

Caption: Peter Draper and Janelle McGufficke on land Peter has prepared for irrigation.

Citation

Land & Water Australia. 2010. Less irrigation raises question of environmental effects . [Online] (Updated March 30th, 2010)
Available at: http://lwa.gov.au/node/3729 [Accessed Tuesday 26th of April 2011 12:50:17 PM ].