Effect of row spacing on vegetative structure, fruit characteristics and oil productivity of N-S and E-W oriented olive hedgerows

The effect of row spacing on fruit characteristics and production was studied in two super-high density olive hedgerow orchards planted at three row spacings (5.0, 4.0 and 2.5 m) with the same intra-row tree spacing, one with rows N-S and the other E-W. For both row orientations, reduction of spacing from 5.0 to 4.0 and 2.5 m added on average 39 and 107% more canopy volume and external surface area per hectare, respectively. In N-S hedgerows, cumulative oil production per ha during the first five years increased significantly by 14 and 52% in 4.0- and 2.5-m relative to 5.0-m spacing. In E-W hedgerows, accumulated oil production per ha did not respond to row spacing. The explanation was found in significantly fewer fruits per unit length of hedgerow and smaller oil content at 2.5 m than 5.0 m spacing in E-W but not in N-S. In N-S hedgerows, there were no differences in oil production and fruit characteristics between opposing sides in all row spacings. In E-W hedgerows spaced at 5.0 m, fruit characteristics were similar between opposing sides, but at 4.0 m and 2.5 m spacings, fruits on S sides were heavier and more mature than on N sides, revealing the impact of lower transmission of irradiance through the hedgerow in closer spacings. Optimal spacing for maximum production depends on row orientation. In N-S hedgerows, the most productive orchard, during the first five years was that planted at 2.5 m, but in E-W hedgerows 5.0 m spacing was the more profitable option. (C) 2015 Elsevier B.V. All rights reserved.