Early performance of Australian multi-cultivar density optimisation trial

Australian almond growers seek to achieve the improved production efficiencies offered by high density plantings without forfeiting their traditional operational practices and machinery. The optimum within-row planting density for traditionally trained, free-standing orchards is yet to be defined for industry relevant cultivars grown in Australia. In 2018, a 5 ha experiment was established in the South Australian Riverland to test the performance of four almond cultivars grown across a six-step density transition ranging from 308 to 615 trees ha^-1. Early yield assessments suggest cultivars respond differently to planting density. ‘Nonpareil’ showed the strongest response with cumulative kernel yields from fifth leaf trees being 45% greater at the highest density (7.5 t ha^-1) compared to the lowest density plantings (5.2 t ha^-1). Cumulative yields from fifth leaf ‘Vela’ (10 t ha^-1) and ‘Carina’ (8 t ha^-1) showed a 10% improvement that peaked at 440 trees ha^-1. ‘Shasta’ showed the weakest density response with similar cumulative yields (7.1 t ha^-1) across all spacings. The incidence of kernel quality defects varied with cultivar but was not significantly impacted by planting density.