RESEARCH & EVENTS
Caution advised when comparing super-high-density( SHD) and conventional almond planting systems
SARDI Almond Production Research Team The Department of Primary Industries and Regions research division, South Australian Research and Development Institute( SARDI)
CURRENT research at the Almond Centre of Excellence( ACE) suggests that moderate increases in planting density(~ 500 trees / ha) can enhance yields without significantly increasing production costs. In pursuit of further efficiencies, SARDI has also been investigating the potential for super-high-density( SHD) production systems as part of its contributions to Hort Innovation’ s National tree crop intensification program( AS18000). While SHD appears to have potential for some parts of Southern Europe, ACE field experiments and associated economic analysis suggest that SHD systems are not yet viable under current Australian production and market conditions.
SHD in Spain Spain’ s almond industry is largely characterised by low-density, rain-fed orchards situated on marginal land, typically producing yields below 0.6 t / ha. Local growers and institutional investors see the potential for yield improvements, but expansion is constrained by water scarcity, stringent EU regulations on inputs and a shortage of suitable land. In response to these limitations, some producers have adopted SHD systems( approaching 2,500 trees / ha) that appear to suit the production of hardshell cultivars under Spanish growing conditions. Although Spanish SHD orchards generally yield less than 2 t / ha, largely due to limited water(< 7 ML / ha) and nutrient(< 100 kg N / ha) inputs, proponents argue they can be economically viable, especially in the early years, thanks to several regionspecific advantages. These include:
• Lower tree costs, reducing the cost burden of SHD setup
Vela super-high-density trees( up to 1,481 trees / ha) at the ACE experimental orchard( 2025)
• Self-compatible cultivars, enabling single cultivar valve units and reducing( or eliminating) the need for beehive pollination
• Relatively inexpensive( albeit limited) water resources
• Affordable orchard labour, with wages equivalent to $ 17- 21 / hr AUD
• Efficient single-pass mechanical harvesting, further reducing labour requirements / costs Additionally, some growers benefit from operational synergies by colocating SHD almonds with SHD olives or vineyards, enabling shared use of machinery and management practices.
SARDI’ s experience with SHD at ACE In recent years, SARDI have tested a modified version of SHD at the ACE experimental orchard in Loxton, South Australia. The study looked at the response of two self-compatible cultivars( Shasta and Vela) grafted to three sizecontrolling rootstocks( Controller 6, Controller 7 and Rootpac 40) across planting densities ranging from 635 to 1,481 trees / ha. Full results to be published through Hort Innovation. By the experiment’ s fifth leaf, the better performing Vela combinations demonstrated three seasons of promising yields, averaging 4 t / ha, with resource use efficiencies aligning with Spanish SHD benchmarks at ~ 3 ML and 50 kg N per tonne of kernel. Vela was well suited to the hedge system thanks to its weeping growth habit, supporting spur renewal, and internal bearing nature, limiting crop loss during in-season hedging( unlike the tip-bearing Shasta). While Vela’ s later harvest timing
36 In A Nutshell- Winter 2025 Vol 26 Issue 2