Mechanical pruning of european hazelnut: Effects on yield and quality and potential to exploit its by-product

Introduction - Annual pruning of mature hazelnut orchards is commonly carried out by hand during the dormant phase of the plants and primarily it is limited to a few cuts aimed to removing dead, damaged, and bad oriented branches. Furthermore, due to the recent implementation of large hazelnut farms in various growing areas, new approaches to the mechanized pruning are highly required. Objectives - The aim of the study was to evaluate if two different mechanical pruning treatments affected yield and nut and kernel quality in European hazelnut. Material and methods - In 2014 a trial was established in central Italy on hazelnut cultivar ‘Tonda Romana’ through the application of two different pruning treatments carried out using a mechanical hedger applied to the tractor. The first treatment was done running lateral and top cuts of some plant rows (treatment A: 2 hedging and 1 topping), whereas the second one was carried out applying lateral cuts only (treatment B: 2 hedging). Mechanical treatments were compared with un-pruned plant rows subjected to the remove of dead branches when necessary (treatment C). Measurements were focused in determining the removed wood and in evaluating production, nut and kernel traits, and nut defects depending on the pruning treatments, over three years. Results and conclusion - The intensity of mechanical pruning has only slightly influenced the cumulative yield, whereas it has significantly increased the nut traits. Furthermore, treatment differences have arisen for the amount of wood mechanically cut, suggesting the use of this biomass leftover for energy purposes. © ISHS 2021.