This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Horticulture in the Murray Darling basin in previous years had seen a steady erosion of a historically secure and readily accessible water supply and during drought this trend had led to a near unsustainable cost of irrigation water.

The almond industry had recognised that its successful future would increasingly depend on the adoption of strategies that ensured the most effective and efficient use of irrigation water including the use of deficit irrigation.

As a consequence the industry in collaboration with the Victorian Department of Primary Indus-tries (DPI) in 2009 established a research project that evaluated the potential of strategic deficit irrigation in almond production.

A large field experiment on a commercial property gave important insights into the performance of Nonpareil under deficit irrigation.

• Trees with deficits applied throughout the irrigation cycle adapted more readily to reduced water than those receiving deficits where the stress was biased toward pre-harvest.
• Irrigating at 85 per cent or more of normal practice had no negative impact on kernel size and yield but irrigating at 70 per cent or less decreased kernel yield regardless of strategy.
• Irrigating at 85 per cent or more of normal practice, which represented a moderate deficit compared to fully irrigated trees (100 per cent ETc), had good potential to alleviate water shortages without loss of production.