Effect of rejuvenation pruning on the olive yield of different cultivars in a super-high-density olive orchard

The adequacy of olive canopy dimensions for over-the-row harvesting machinery is one of the most important management practices in super-high-density (SHD) olive orchards. Manual pruning performed every year can control canopy dimensions and also exposure of the tree to sunlight. An adequate balance is required between the removal of woody non-productive branches and the maintenance of a large quantity of reproductive shoots. When excessive canopy development occurs, a severe pruning intervention can be a solution to recover orchard productivity. This paper presents results obtained after rejuvenation pruning of an SHD orchard with excessive canopy dimensions. The SHD orchard was established in March 2002 in Herdade dos Lameirões, Safara, Moura, Portugal (38°04'N 7°16'W). The orchard was planted according a randomized complete block design with three replications. The orchard has two densities, 1850 trees ha^-1 (4×1.35 m) and 1250 trees ha^-1 (4×2 m), planted with six cultivars ('Azeiteira', 'Cobrançosa', 'Cordovil de Serpa', 'Galega vulgar', 'Redondil' and 'Arbequina'), leading to 36 plots each composed of three rows. The pruning was performed in April 2010. It consisted of mechanically topping the canopy parallel to the ground at 2.5 m and hedging of each side close to the central leader of the trees, followed by a manual pruning complement to remove the remaining branches. Olive production was recovered in the second year after pruning. Significant differences were found among results of different years and among the cultivars, with regard to olive yield per hectare. The highest yield was registered in the third year after pruning. Planting density had a significant effect on yield per tree, with higher production in the 4×2 m array.