Canopy and root growth of young olive trees in a high-density orchard

Rapid vegetative growth and early onset of fruit production are requirements for young olive trees in high-density orchards during the first years after planting. Strong development of the root system is also required to ensure good water and nutrient uptake and to accelerate canopy growth to create a hedgerow system. The root expansion along the row and the inter-row and the relationship with the canopy development in high-density plantings require more detailed investigations and can supply helpful information to guide the vegetative growth during the years after planting. The growth of the canopy and of the root were assessed in young ‘Maurino’ olive trees in a high-density orchard (1,250 trees ha-1). In particular, tree height, canopy dimensions, and trunk diameter at 20 cm height from the ground were measured two years after planting. At the same time, soil samples at 0-15 and 15-30 cm depths were collected with a manual auger at 30 and 80 cm distance from the trunk in the inter-row and intra-row directions. Samples were soaked, the roots were separated from the soil, then dried and weighted, their length and diameter measured, and density calculated. Results showed a different root development in the inter-row and intra-row directions and root length, diameter and density change according to the distance from the trunk and the sampling depth. The root development was correlated to the trunk and canopy dimensions in order to provide information about the below- and above-ground growth of the young trees two years after planting.