A new device to improve the mechanical winter pruning in olive trees hedgerows.

The economic success of superintensive olive plantations is mainly due to the full mechanization of the harvesting and pruning. While the advantage of straddling machines is undoubted, winter mechanical pruning determines falls in productions. This is due to the indiscriminate suppression of both fertile leafy shoots destined to fruiting and growth, and exhausted parts of the plant. To reduce this damage, an innovative device has been developed, applied to a pruning machine, able to selectively cut the “aged” parts of vegetation. The selection is achieved by an air’s fluid dynamic action obtained throughout defined and directional air jets able to push the young and flexible shoots upwards and downwards; in this way they are saved by the cut, regenerating at least one year in advance the new fruiting hedge. Tests were carried out on the cultivar Arbequina, Tosca and Sikitita, in three superintensive olive groves located in the province of Grosseto, Rome and Latina, assessing the amount of leaves, shoots and branches, as well as fruits present at harvest, preserved from the pruning thanks to the action of the air flow, respectively for the East and West side of the rows. To get a profile of the biomass distribution along the cross section of the tree canopy, in the Grosseto farm a trial was also carried out to better assess leaves, shoots and branches distribution in the canopy. The statistical data analyses immediately evidenced two different populations due to the selective pruning. The work highlighted the remarkable effectiveness of the air jet in safeguarding the flexible and leafy vegetation and allowed to quadruple leaf surface and production.