Sunraysia irrigation information now even better

13 July 2023

For nearly 30 years Agriculture Victoria has been supplying Sunraysia irrigators with weekly information on evapotranspiration (Eto). Now we are making it even more helpful.

Agriculture Victoria Irrigation Extension Officer Maxine Schache said evapotranspiration is an estimate of the loss of water from both plants and the soil.

‘The main drivers of evapotranspiration are sunlight, wind, humidity and temperature.’

‘Evapotranspiration information is used by farmers to more accurately schedule irrigations to help achieve top yields and improve water productivity,’ she said.

For many years Agriculture Victoria has provided weekly Eto information on a graph for Mildura, Red Cliffs and Robinvale irrigators.

‘Irrigators can overlay the generic graph to reflect the water use of the crop(s) grown on their property.

‘However, one of the issues has been that it’s always been retrospective - for the last 7 days.

‘With better predictive information now being available we will be including the coming week’s daily Eto values as well for both Mildura and Robinvale,’ she said.

‘This will help irrigators make better decisions on when to order water, particularly as there is more drip irrigation in the vineyards and orchards that need to be irrigated more frequently than weekly.

‘The Eto values are calculated from weather station readings of solar radiation, temperature, humidity and wind.’

Ms Schache also noted that given Mildura and Red Cliffs are close both geographically and meteorologically, Agriculture Victoria will no longer supply information for Red Cliffs as part of the information upgrade.

This is because the Eto values for Mildura are almost identical to Red Cliffs and can be used with a great deal of confidence.

Ms Schache said irrigators shouldn’t rely on the evapotranspiration graph alone to schedule their irrigations.

‘Best results are obtained when used in combination with soil inspection, soil moisture sensors and growers’ own experience, as well as other indications of crop stress.’

More information is available on the Agriculture Victoria website.

Media contact: Mel Curtis

Phone: 0402001853