Preliminary Results about the Influence of Pruning Time and Intensity on the Vegetative Growth and Fruit Yield of a Semi-intensive Olive Orchard

The effect of extending the pruning time and reducing the pruning intensity was investigated on vegetative response and production of three Italian olive cultivars (‘Raggia’, ‘Maurino’ and ‘Leccino’) in central Italy. From 2009 to 2011, pruning was performed on 5-years-old olive trees in early spring (after bud break) at two intensity levels (minimal and heavy) and in late spring (after full bloom) at a heavy intensity. A control set of plants was left unpruned during the experiment. Results showed that the absence of pruning minimized water sprouts growth and initially generated the highest yield. The productive advantage offered by not pruning decreased at the third year. After 3 years of no pruning, the plants showed an excessive height, shading of the central portion of the canopy, and negligible vegetative growth, inducing an early senescence of the productive branches and necessitating the removal of a massive amount of dry material by applying a severe pruning operation (rejuvenation) at the end of the trial. The early spring minimal pruning technique led to the lowest amount of pruning material and provided a consistent increase in plant production compared to heavy pruning. Late spring pruning did not provide competitive advantages in terms of vegetative re-sprouting control nor yield compared to early pruning. This preliminary study suggests early spring minimal pruning in central Italy as the best practice to increase stability in yield and to control the vegetative growth of olive trees in semi-intensive orchards.