Trials on the Convenience of Mechanical Pruning of ‘Tonda Gentile delle Langhe’ in Piedmont

To obtain robust and extensible experimental results on the agronomic convenience of mechanical pruning of old bush trained hazelnut orchards in Piedmont, during the period 2006-2010 four trials to compare mechanical, manual and no pruning trees were made in 4 representative locations (=orchards). The orchards, located on flat or sloping grounds and growing TGL trees 6 to 18 years old, were pruned in March or in September, obtaining for each location 6 plots of 10-15 trees replicated twice and pruned once during the period 2006-2008. Observations generally regarded: pruning duration (s/tree) and amount of pruned wood; yielding and nut quality for at least 3 years after pruning operations. The results of the four trials were the following: - mechanical pruning duration was 1.4-3.9% higher than that of manual pruning. These figures can increase to 8-10% if device position time, manual finishing of larger cuts and desuckering are also considered; - the cumulative yield, 4 years after pruning operations, is equal but often greater for the mechanically pruned trees compared to non-pruned or manually pruned ones. These results are evidenced both in March and September trials. The cumulative production of manually pruned trees reached the amounts of the nonpruned plots only after 4-5 years. The convenience of pruning both by mechanical or manual system is evident starting from the first year after the cuts because of the better technological traits of nuts (e.g., seed weight, commercial rate, incidence of external and internal defects). However, these results are not registered for the younger orchard.