Cultivar and Tree Density As Key Factors in the Long-Term Performance of Super High-Density Olive Orchards

Abstract

Super high-density (SHD) olive orchards are rapidly expanding since the first plantation was set up in Spain in the 1990s. Because there are no long-term studies characterizing these systems, it is unknown if densities above a certain threshold could trigger competition among fully-grown trees, compromising their development. Over 14 years we have evaluated the performance of the major olive cultivars currently planted in SHD systems (“Arbequina,” Arbequina IRTA-i·18, “Arbosana,” “Fs-17,” and “Koroneiki”) and nine SHD designs ranging from 780 to 2254 trees ha−1 for the cultivar “Arbequina.” Remarkably, the accumulated fruit and oil production of the five cultivars increased linearly over time. Our data indicated the favorable long-term performance of the evaluated cultivars with an average annual oil production of 2.3 t ha−1. Only “Fs-17” did not perform well to the SHD system in our conditions and it yielded about half (1.2 t ha−1) of the other cultivars. In the density trial for “Arbequina,” both fruit and oil accumulated production increased over time as a function of tree density. Thus, the accumulated oil yield ranged from 16.1 t ha−1 for the lowest density (780 trees ha−1) to 29.9 t ha−1 for the highest (2254 trees ha−1). In addition, we note that the accumulated production per surface unit showed a better correlation with the hedgerow length than the tree density. Thus, the current planting designs of SHD olive orchards can be further improved taking this parameter into account. Despite observations that some irregular patterns of crop distribution have arisen, our olive hedgerows are still fully productive after 14 years of planting. This result contradicts previous experiences that showed declines in production 7 or 8 years after planting due to high vigor, shading, and limited ventilation.

Yield and Water Productivity Responses to Irrigation Cut-off Strategies after Fruit Set Using Stem Water Potential Thresholds in a Super-High Density Olive Orchard

“…Unfortunately, the pruning done in the 2012–2013 season prevented the assessment of alternate bearing in the last two seasons. Such a pattern is common in most olive cultivars (Lavee, 2007). This often occurs because in the “on” year there is low shoot growth, which leads to few potentially reproductive buds for the next year; when crop load is high there is inhibition of floral induction (Dag et al, 2010; Fernández et al, 2015).…”

Regulation of On-Tree Vitamin E Biosynthesis in Olive Fruit during Successive Growing Years: The Impact of Fruit Development and Environmental Cues

“…Olive trees have a high production year (“on year”) but a reduced one the following year (“off year”) (Lavee, 2007; Turktas et al, 2013). Empirical observations in the experimental orchard suggest that production was further decreased during the 3 rd year in comparison with the 1 st and 2 nd years, while fruit ripened earlier.…”

“…The significant reduction of tocochromanols, VTE5 content and antioxidant capacity in olives could therefore be partly explained by the quicker ripening observed in the 3 rd year, which causes earlier chlorophyll degradation and more evident carbohydrate metabolism, fatty acid and triacylglycerols (TAGs) biosynthesis. In addition, stressful environmental conditions could also account for the lower olive production observed during the 3 rd year (Lavee, 2007; Turktas et al, 2013). …”

Partitioning of Dry Matter into Fruit Explains Cultivar Differences in Vigor in Young Olive (Olea europaea L.) Trees

“…So far, the cultivars that proved most suitable for SHD olive orchards are Arbequina, Arbosana, and Koroneiki (Tous et al, 2006), three cultivars characterized by low vigor compared with most traditional cultivars (Rosati et al, 2013;Tous et al, 2006). However, they are also characterized by early and abundant bearing, as well as low alternate bearing (Caruso et al, 2012;Díez et al, 2016;Farinelli and Tombesi, 2015;Godini et al, 2011;Moutier, 2006;Moutier et al, 2008). Trees of these cultivars produce large crops, relative to their size, already in the second and third year after transplanting.…”