Should we talk about non-mutilating pruning or pruning respects the sap Flow?

[TEAM VMP ACADEMY]

The objective of vine pruning is to fix the yields per vine and per hectare by fixing the number of latent buds per m2.

The latent buds or winter buds carry the inflorescence primordia (usually two/ bud) which will determine the harvest potential of the new year to come.

There are several types of pruning: Cordon de Royat (spur pruning), Guyot (cane pruning), Chablis pruning, Cazenave pruning, mixed pruning (Cordon and Guyot)

Pruning by essence is a mutilating operation for the plant and the pruning wounds can cause induced necrosis of the tissues underlying the pruned organ: Phloem + cambium + xylem (wood) = sap conducting system.

Is it possible to avoid tissue necrosis following pruning wounds? No…

So what can we do ?

When pruning, it is advisable to limit these necroses as described in https://lnkd.in/eR29N_YD (the article exists in 6 languages).

This is called gentle pruning and its consequence is the respect of the sap flow (elaborated sap = secondary phloem and raw sap = secondary xylem or wood).

The principle is to limit the proportion of necrotic tissues in relation to living tissues: = proportion of brown/black tissues (therefore necrotic) in relation to “white” tissues (therefore living) easy to observe by making cuts in the organs of the vine such as the arms and/or the spurs.

(a), (b) and (c): examples of small necroses induced by pruning of shoots even if a snag has been put in place by the pruner; (c): example of the proportion of healthy and necrotic wood in a spur; it is sufficient that the proportion of healthy tissue is greater than the proportion of necrotic tissue to ensure optimal conduction of the sap and the sustainability of the vineyard

The winning strategy over the years is to create wood.

This is why for example:

1) Cordon pruning: it is recommended to mount the spurs in turrets rather than cutting them back

2) Guyot pruning: avoid forming a crown head

Finally, it is up to each winegrower to decide to adopt (or not) the non-mutilating pruning according to his objectives and means.
Pruning the vine cannot be improvised, a training in pruning is necessary.

A. Deloire