Peri urban water saving
From the October 2008 edition of Agriculture Today.
More than 2000 commercial irrigators operate in peri urban Sydney.
Many of them are town water users on two hectare holdings.
Below average rainfall over several years has resulted in water use restrictions introduced by Sydney Water.
The irrigators are also highly visible, resulting in intense environmental scrutiny by regulators and the general public.
Consequently, NSW Department of Primary Industries (DPI) and the University of Western Sydney received funding to evaluate the capacity of two innovative technologies, to both reduce potable water use and limit off-site effects of any runoff from these peri urban farms.
The main objective of the study was to better understand the concerns and issues of farmers while evaluating KISSS sub surface irrigation technology and the Irrigation Water Recycling System (IWRS) under field situations.
"KISSS applies water directly to the root zone of plants with a minimum of water loss through runoff, evaporation and deep drainage," DPI irrigation officer, Bill Yiasoumi, said.
"In this system, water is applied below the ground surface directly to the plant’s roots area, resulting in a significant improvement in water application over traditional drip irrigation systems.
"Also, since the water is applied below the surface, water waste due to evaporation is almost eliminated."
Mr Yiasoumi said the IWRS collects irrigation and rainwater runoff from cropped areas during sprinkler irrigation and minor rain events and stores it within the farm for reuse in the next irrigation.
"Overall, the IWRS is designed to improve the availability of a farm’s irrigation water supply and reduce nutrient runoff," he said.
The study adopted a participatory approach with eight farmers involved, and a number of other stakeholders.
An initial survey of target farmers found their ethnicity, technical knowledge, their individual perception of water scarcity and their economic conditions to be important indicators to their commitment and motivation to test and monitor the two systems on their farms.
Other issues affecting them included the escalating costs of water and fertilisers, the considerable variability in profits as vegetable prices fluctuate and large time inputs required to market produce.
Mr Yiasoumi said many farmers were initially reluctant to get out of their comfort zone and consider either system over their current practices, despite the potential water savings and environmental protection.
However, through demonstrations, particularly of KISSS showing a faster wetting zone, uniform crop growth and water savings, they were encouraged to evaluate and monitor either or both.
The project is continuing and Mr Yiasoumi said early indicators pointed to considerable water savings from both technologies.
Contact Bill Yiasoumi, Richmond, (02) 4588 2107, bill.yiasoumi@dpi.nsw.gov.au
