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Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.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?

By the mid to late 1990’s, the Australian almond industry had developed and adopted world’s best practices and had reached a point where it was producing equivalent or slightly greater yields than the Californian industry, achieving a benchmark kernel yield of 2.45 tonnes per hectare. The Australian almond industry sought to continue this development but regarded the traditional approach of researching and adopting new, but discrete technologies as too slow in advancing orchard management.

The industry required a holistic approach to water, nutrition and canopy management. To achieve this objective it engaged Professor Rafael Assaf, previously of the Volcani Institute of Israel to conduct a R&D project. The aim was to combine the key disciplines of soil science, physiology, nutrition and irrigation to develop management options with optimal efficiencies and efficacy, to substantially enhance tree crop performance.

The Sustainable Optimisation of Australian Almond Production trial was set up in 2001 on a three year old, 7.64 hectare almond orchard, located on the commercially operated property of Clark-Taylor Farms, in Berri, South Australia.

The trial consisted of seven experimental treatments; three irrigation treatments, three nutrition treatments and one treatment that continued existing property management of irrigation and nutrition. The irrigation and nutrition treatments all received the same foliar nutrient applications and pruning regime.

The key outcomes of the trial were:

• An average kernel yield of greater than 4.0 tonnes per hectare was achievable.
• Successful management of almond orchards using drip irrigation rather than the traditional approach of sprinkler irrigation was achievable.
• Increased tree crop performance by daily managing water and nutrient requirements.
• An optimal application rate of 13 ML/ha suitable for drip irrigated almond orchards.
• No additional yield benefits were observed with nitrogen and potassium applications above 240 kg/ha and 400 kg/ha, respectively.
• Nutrient loss beyond the root zone was apparent through late winter, early spring and post harvest and needs to be monitored and managed.
• High water application rates (>1132mm or 11.32ML/ha) led to increased vegetative growth, without an equivalent significant increase in yield.
• A higher application of water led to increased shading and a greater need for pruning.

The key recommendations for future R&D were:

• A requirement to continue researching the nutritional requirements and application protocols of almond orchards.
• The need to review and produce new critical values of almond leaf tissue analysis.
• Research the potential use of more vigorous rootstocks to maintain or continue to improve yield by more efficiently utilising water and nutritional inputs.
• Research the potential to increase tree densities, “lower” water and nutrient inputs and maintain light interception, bud numbers and high yield through more fruiting units (i.e. trees) – not inputs.

Whilst a “recipe” outlining the best water and nutrition inputs for almond orchards was ideal, it did not suit every orchard. To ensure successful practical application, individual onsite execution was required.