Trial investigates watering regimes

Department of Agriculture and Food researchers are tapping into water-use efficiency for WA tomato growers.

DAFWA development officer Rohan Prince conducted a trial at Carabooda grower George Kyme's property, growing Swanson tomatoes.

The tomatoes, harvested this month, proved adjusting irrigation to account for changes in evaporation rates and soil type was the key to much more efficient water use.

Mr Prince said preliminary work had showed comparatively little sideways spread of water through the soil, encouraging placement of drippers 20cm apart rather than the standard 25cm.

"This is ensuring that more water is getting into the root zone and contributing to faster growth and more efficient water use," Mr Prince said.

"This often means that the 'best practice' tomatoes in the trial are receiving more frequent but lighter watering than normal grower practice."

Irrigation scheduling on the 'best practice' rows is decided each day based on evaporation in the local area and measured at the department-run Wanneroo weather station.

This information plus the growth stage of the crop determine how much water is applied. This leads to efficient use of water, only applying as much as the crop needs each day.

"More efficient water use also means that pumping time is reduced, lower fertiliser input is needed, less drainage to the groundwater and extra water for other crops," Mr Prince said.

The trial of 4800 Swanson tomatoes was planted onNovember 7 and is now being harvested.

Overall water use and yield comparisons will not be available until the end of the season in early March.

Commercial growers wanting more information or a tour should contact Mr Prince on 0429 680 069.