Precision short pruning in viticulture

Precision viticulture Pruning and vineyard management Precision agriculture

In order to reduce the costs and time required for pruning the vine, Precision Close Pruning (PCP) is attracting increasing interest in the wine industry. According to estimates^[1], pruning can represent up to 33% of costs, more than half of which is due to manual pruning of vines, which can represent up to 50 hours of work per hectare. It is one of the last manual work tasks, while almost all vineyard operations are mechanized or mechanizable (harvesting, shoot thinning, soil work…).

What is precision close pruning?

Precision close pruning is an extreme form of mechanized pruning. This pruning is done at one or two buds maximum, about 2 cm above the cordon. Pruning time varies: between 2 and 4 hours per hectare for the machine pass. The shoots not cut by the mechanical pruning are then removed by hand, which can represent from 8 to 30 hours per hectare, depending on the machine used, the grape varieties and the stage of the vine.

Precision Close Pruning (PCP) is easily achievable thanks to advances in vineyard machinery. There are now many models, more or less automated, allowing to reduce the follow-up time and halve pruning costs.

Prerequisites for implementing precision close pruning

Choice of plots

Precision close pruning is preferably used on vines pruned in cordon de royat. Indeed, PCP requires a straight cordon, a terrain as flat as possible and long rows, which allows better pruning quality and less manual follow-up.

Plots must also have:

shoot lengths as regular as possible,
the trellising as rigid as possible, metal stakes protruding beyond the carrying wire must be removed (prefer bamboo or plastic stakes),

If vines are trained on Guyot (or double), it is necessary to switch to unilateral cordon before starting Precision Close Pruning.

Suitable trellising and density

Precision close pruning requires good quality trellising:

anchors capable of supporting heavy loads: the weight of the vegetation and machine passage
stakes must be reinforced and spaced a maximum of 5 meters apart
twisted wire with a minimum diameter of 3.4 mm with a breaking load of about 500 kg
carrying wire at 0.80 m for grape varieties with drooping habit while keeping lifting wires to maintain sufficient leaf area for optimal ripening (for Syrah for example)
carrying wire at 1.20 m for upright grape varieties (position the carrying wire at the top of the stake to avoid collisions between discs and the stake)
stakes must remain below the carrying wire (to avoid collisions between discs and stakes: prefer bamboo)
spacing between vines must be between 0.90 m and 1.10 m
row width must be between 2.20 m and 2.50 m
cordon height must be between 0.70 m and 1.50 m

What machines are available?

The Pellenc PCP is the only model to automatically manage the machine positioning relative to the cordon (Visio system). There are other less automated models (Brunel, CGC Agri, Terral). These machines reduce follow-up times (up to 8 hours per hectare). Pruning costs are then halved.

Machine costs range between €12,000 and €21,000 excluding tax.

For more information on precision close pruning machines on the market: https://tarn.chambre-agriculture.fr/fileadmin/user_upload/Occitanie/074_Inst-Tarn/1-PRODUCTIONS_TECHNIQUES/Viticulture/Documents_techniques/materiel/taille_rase_2011_TM.pdf

What are its advantages?

Precision Close Pruning allows working at 2-3 km/h compared to 1-2 km/h in manual pruning.
Trials^[2] conducted in vineyards show a significant yield increase in the first year (+20 to +70%) which diminishes after 2 to 3 years of establishment.
There are more clusters per vine, they are more uniform and small in size. This allows good aeration of the vines and thus optimizes phytosanitary treatments.
Labor savings are about 30 hours per hectare depending on manual follow-up.
Less wood breakage due to wind.
Better distribution of the harvest along the cordon.

What are its disadvantages?

Precision close pruning requires cordon pruning, so preparation or conversion time of the vines must be considered.
Precision close pruning is not applicable in vineyards claiming an AOP (due to the pruning specifications in the production rules).

Sources

Chamber of Agriculture of Tarn, Mechanizing pruning: precision close pruning
French Institute of Vine and Wine Occitanie, PRECISION CLOSE PRUNING, HEDGE PRUNING AND MINIMAL PRUNING

Appendices

↑ estimates made by the IFV Sud-Ouest using the VITICOÛT® software
↑ Precision Close Pruning (PCP) has been used in Italy for many years under the impetus of Professor Cesare Intrieri's work. Several experiments monitored by the Chambers of Agriculture of Gard and Vaucluse have been conducted with two pioneering winemakers (Mr. Henri in Arles and Mr. Allemand in Jonquières).

Est complémentaire des leviers

Mechanizing pruning in viticulture

[1] stimates made by the IFV Sud-Ouest using the VITICOÛT® software

[2] Precision Close Pruning (PCP) has been used in Italy for many years under the impetus of Professor Cesare Intrieri's work. Several experiments monitored by the Chambers of Agriculture of Gard and Vaucluse have been conducted with two pioneering winemakers (Mr. Henri in Arles and Mr. Allemand in Jonquières).

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