Three Years Evaluation of the Use of Mechanical
Pruning in “Rocha” Pears
Dias, A.B.1, Patrocínio, S. 2, Pereira, S. 2, Pinheiro, A.1, Peça, J.O. 1
Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM)/Departamento de
Engenharia Rural da Universidade de Évora
Núcleo da Mitra, Apartado 94, 7002-554 Évora, Portugal
Email: [email protected]; [email protected] ; [email protected]
2
Cooperfrutas CRL
Quinta das Freiras, Ponte do Jardim, 2460-617 Alcobaça, Portugal
Abstract
Manual pruning with pneumatic shears is a current practice used by pear
farmers in Portugal. As an alternative, mechanical pruning performed by a tractor
mounted cutting bar provided with circular disc-saws can be used.
A trial to evaluate the use of the tractor mounted cutting bar in the pear
pruning, were conducted between 2008 and 2010, in a commercial orchard of Rocha
variety. The orchard was planted in an array of 4m x 2m and the trees are trained as
the central leader system.
In this trial, in a randomised complete block design with three replications,
three treatments (T1, T2, T3) are being compared leading to 9 plots with three lines
of 10 trees per plot. In each plot the central line is used for parameters evaluation.
The treatments under study are: T1 - manual pruning performed by workers
using pneumatic shears, in each year; T2 - mechanical pruning, topping the canopy
parallel to the ground, in each year and hedging in the two sides of the canopy, in
2008 and 2010; T3 - mechanical pruning, topping the canopy parallel to the ground,
in each year and hedging in the two sides of the canopy, in 2008, followed by a
manual pruning complement each year.
Tree height and width was measured, before and after pruning interventions.
Pruning operation was timed and pear yields evaluated.
Mechanical pruning seems to be effective in controlling tree size leading to a more
uniform orchard when compared to manual pruning.
The use of the tractor mounted cutting bar can contribute to increase working rate
of the manual pruning complement.
At the third year of the trial, a decrease in pear production was registered in the
trees exclusively submitted to mechanical pruning, suggesting that a manual pruning
complement was necessary. More years of field work are essential to validate these
results.
Keywords: tractor; cutting bar, disc-saws, work rates, pear production.