Lemon trees response to different long-term mechanical and manual pruning practices

Abstract

Mechanical pruning can be integrated into a management strategy to reduce pruning costs in lemon [Citrus x Lemon (L.) Osbeck] orchards. The present study evaluates mechanical pruning combined with manual pruning in the ‘Fino 95’ lemon cultivar over four years. Five pruning treatments involving different intensities of mechanisation have been carried out: (1) manual pruning (control); (2) mechanical pruning of all the tree (topping, skirting and both sides hedging) in even years and manual pruning of all the tree in odd years; (3) top and skirts mechanically pruned and follow-up manually pruned; (4) mechanical pruning of all the tree with the exception of a lateral side and manual pruning of that half side of the tree; and finally, (5) mechanical pruning of top, skirts and one side of the tree, with the opposite side remaining unpruned, and alternating the pruned and unpruned sides yearly. Pruned biomass, pruning costs, yield, fruit size and net economic value have been analysed. The results of four years of observations have proved that the treatment of manual pruning alternated yearly with mechanical pruning and the treatment of exclusively mechanical pruning reduced the time required to perform the task, and also increased the economic benefit obtained, with respect to manual pruning. Farmers will find the treatment of mechanical pruning alternated annually with manual pruning to be more acceptable, since the tree management differs very little from the traditional system. The treatments consisting in manual and mechanical pruning (3 and 4) carried out in the same year obtained the worst results: they failed to reduce the time required to perform the task, and did not increase the yield and consequently the economic profit.