Effect of different winter pruning systems on grapes produced

Abstract

The purpose of these trials was to evaluate possible effects on properties of grapes, particularly the physical and mechanical features, depending on the winter pruning system. The following pruning techniques were carried out: manual pruning (m); mechanical pruning (M); mechanical pre-pruning and subsequent manual finishing (Mm); mechanical pre-pruning and contemporary fast manual finishing, using a wagon facility with two operators equipped with pneumatic scissors (Mw). The trials were carried out on Sangiovese trained to spurred cordon. During the trials were measured: time and cost of pruning, quality of pruning and the vegetative-productive response of vines. During grape harvesting a consolidated analytical method of texture analysis was applied to evaluate the physical parameters of grapevine cultivar: pedicel detachment, skin perforation, skin thickness, grape features as hardness, cohesiveness, springiness. Analysis of working time showed that the manual pruning (m) determined a greater commitment of time, while the mechanized pruning (M) presented a time reduction of 95%. The two mechanized pruning associated with manual finishing reduced the time of 21% (Mm) and 69% (Mw). The lowering cost is less evident but important anyway. Regarding the quality of pruning, the increase in the level of mechanization has produced an increase of spurs and buds density. It was also detected a higher percentage of damaged spurs and in wrong position. The increasing of mechanization levels of pruning also has produced smaller and sparser bunches with smaller berries. The study of mechanical properties of berries showed significant differences in the mechanical behaviours of the different pruning tests. The mechanized pruning presented higher values for the pedicel detachment, skin perforation and cohesiveness, while it gave lower values for thickness of skin and springiness. The results showed that mechanical pruning can modify properties of the berries which influence mechanical harvesting on vineyard.