Planting density affects vigour and production of 'Arbequina' olive

The hedgerow orchard type is being increasingly used with the olive although not much information is still available about its suitability to this species. The objective of this study was to assess the influence of planting density (312, 416, 625 and 1,250 trees ha(-1)) on vigour and productive characteristics of 'Arbequina' olive trees planted in 2003. Significant linear regressions have been observed between planting density and tree width, trunk cross section area and canopy volume. Increasing planting density showed positive linear correlation (R-2 = 0.63) with canopy volume per hectare. There was a negative correlation between planting density and production per tree in the five first crops, but it was positive with production per hectare both in olive and olive oil production with coefficients of determination ranging from 0.16 to 0.43 and from 0.28 to 0.46, respectively. A significant linear regression (R-2 = 0.31 and 0.48) was found between planting density and fruit size on two of the studied cropping years. Our results have not allowed establishing any relationship between planting density and fruit oil content. Finally, the studied densities did not affect the oil fatty acid composition. The production increase observed at the highest tried density is linked to the increase in canopy volume per hectare, but these results should be checked at later stages of tree development, as this study covers only until the fifth harvested crop.