Vegetable irrigation ideas are extended

Wider adoption of a vegetable irrigation scheduling tool developed in Western Australia is being made possible by the National Program for Sustainable Irrigation.

Vegetable Irrigation Scheduling System (VISS)

Known as the Vegetable Irrigation Scheduling System (VISS) it grew from a goal of vegetablesWA, the state’s peak body representing vegetable growers, to have ready electronic access to advice on when to irrigate and how much to irrigate. It became a reality through a collaboration with the Department of Agriculture and Food WA and funding provided by the WA state government.

While the tool has had reasonable uptake the National Program for Sustainable Irrigation is funding extension activities including field days to raise awareness of its value with the aim of wider and faster adoption.

Georgia Thomas, program manager with vegetablesWA, says the extension project will have extra importance considering increasing pressure to use water wisely and to get the best possible returns from what is available.

“Although VISS is fundamentally a scheduling tool it is also about the principles of good irrigation management and puts a focus on crop requirements and closer consideration of the effects of weather and local characteristics including soil properties,” she said. “Initially it was seen as being particularly valuable for irrigators in sandy coastal regions but there can be wider application of course.”

Demonstrating the system

The system uses real time evaporation information from the Department of Agriculture and Food WA network of weather stations and crop water requirements (whether these are for carrots, potatoes, onions or other vegetables) are based on daily evaporation and plant growth stages. A working demonstration for irrigators can be found on the vegetablesWA website www.vegetableswa.com.au.  Irrigators can be provided with a property and weather information overview. Calculations can be made for each bay and crop, with a running record of planting date, growth stage and watering required. Weather notes include the nearest weather station location, rainfall from midnight to the current time and a forecast summary.

It is advised that new users refine scheduling through field verification and consider property-level characteristics including the “vigour” and water holding capacities of their soil types. They also need to know the operational efficiency of their irrigation equipment.

Example of using the system

The importance of these aspects can be demonstrated by the Ivankovich family, which is a large supplier of carrots and onions, with holdings in the Myalup area which supply domestic and export markets. There have been operational efficiencies with introduction of fixed upright sprinklers and production efficiencies brought about by putting local knowledge and measurements alongside scheduling advice based on evaporation and other factors.

Knowing the evaporative effects of local wind events, for instance, may tell them demand is higher. Generally, however, through knowing infiltration rates and plant responses to the growing environment (which includes soil moisture and nutrient status) it has been possible to apply irrigation and fertilisers below the standard.

“You can pour on a lot of inputs without any gain,” Anthony Ivankovich said.

“These days you have to know what is happening at all points in the operation, which is why we test infiltration prior to planting and have reviewed our fertiliser amounts and timing, which led to us halving pre-plant rates for our carrots and onions.

“Changes which have evolved from greater scrutiny have meant sustaining production while saving water and greatly minimising nutrient leaching into the water sources. We are also seeing a greater evenness of our vegetable crops, good quality and yields, and fewer mildew problems.”

Improving irrigation efficiency

Tom Busher, who has an irrigation property at Dardanup and is WA’s representative on the National Program for Sustainable Irrigation’s program management committee, says the extension project based on VISS is about improving irrigation efficiency and is the type of investment needed at this time.

“Many of the national program’s investments have been set around scientific studies which search for new technologies or seek solutions to problems,” he said.

“Much of this type of work is about generation of new knowledge, whereas the vegetablesWA project is about extension of existing knowledge. This makes it a welcome addition to the National Program for Sustainable Irrigation’s suite of projects.

“Extension projects, we believe, will bring excellent returns if they mean reduced lag time between adoption of better practices by a few and widespread acceptance of these practices as the norm.”

Citation

Land & Water Australia. 2010. Vegetable irrigation ideas are extended. [Online] (Updated May 18th, 2010)
Available at: http://lwa.gov.au/node/3742 [Accessed Wednesday 29th of February 2012 10:17:05 PM ].