At the end of last August, the Ministry of Rural Affairs, through the Galician Agency for Food Quality (Agacal), organized a course on the replacement of marras in vineyard cultivation in which 15 professionals from the sector participated. Thanks to the information extracted from that day and from the work of the professionals of the Guísamo Agroforestry Training and Experimentation Center (CFEA), Campo Galego has been able to prepare a summary with the keys for the replacement of marras in viticultural crops.

To begin with, it must be taken into account that vine plants can die gradually or suddenly for many reasons. The ideal in a replacement is that, at the moment it fails, that space is immediately occupied. In this way, the plants next door are given less time to occupy the vacancy of the failed plant and, as far as possible, it should be replaced at the same time in which it causes loss if that is possible. . If the strain shows signs of disease, you can choose to uproot it so that it can be replaced as soon as possible. If not, neighboring plants can take up your space and make it difficult for you to grow later. At this point, two phases could be distinguished. First it has to develop root in the ground and then occupy the space outside. Plants next to each other are, by default, dominant in the root system and out of the ground due to their ability to absorb most of the light.

In this same context, what CFEA professionals call “soil fatigue” usually occurs. This is defined as that phenomenon where the soil occupied by the plant may be worn out or have some related condition. If the old plant died from a mechanical accident, the soil should not have been affected, but if the decline was caused by fungi, it is most likely that they are still linked to the soil and can attack the replenishment. Therefore, the soil must be conditioned based on the causes of the drop (disinfection, nutritional contributions...) so that it favors the development of the plant and, at a minimum, it should be aerated. One of the most common conditions is that caused by armilaria, basidiomycete parasitic fungi that live on trees or woody shrubs.

“The secret of the replacement of yore is not in making it turn on, but in making a good follow-up from the moment it is turned on and following the biological cycle of that year and the next. Otherwise, the replacement effort will be useless”, explain the CFEA professionals. In the case of the replacement of yore, special attention must be paid to managing the development of neighboring plants to avoid excessive competition for light and for the land space that corresponds to it in the plantation line. This will make it easier for the new root system to have opportunities to occupy the volume of soil that corresponds to it.

However, the casuistry in terms of replacements is very varied. They can be immediate, in which the time in which they are executed prevails; produced by machines or animals, which do not usually have biological problems; due to disease, water stress... There are many factors for which a vine plant can die. From the CFEA they explain that it can be interesting to keep spare parts of plants to be able to make an immediate replacement as soon as the plantation is done, since it is usual that there is a small percentage of casualties, mainly caused by human errors. In any case, winegrowers must make a positive discrimination towards the new ones. They must make sure that it lights up and that the light reaches it easily.

In the experiences that the professionals of the Guísamo Agroforestry Training and Experimentation Center have been developing, more specifically in the practice carried out in 2021, it has not been necessary to water or weed too much the new replaced vines because there was no drought thanks to its conditions climate of the Atlantic area. Although from Guísamo they clarify that the usual thing is to weed and give phytosanitary treatments like the rest of the vineyards. In addition, a stake and a protector are usually placed on each plant to indicate that care must be taken when working with machines or treatments in the middle of the plantation. Although in just one year, the new plantations are usually settled, a process of what specialists call positive discrimination must continue. This means that winegrowers must give priority and advantage to the new vines with respect to the older neighboring ones so that they can gain dominance and occupy the space that corresponds to them within the plantation.

Competitive weed control methods

From the second year of life

During the first and second year of life of the replaced vines, pruning should be carried out, normally leaving two buds alive and thus favoring regrowth. The reason is that they take a good dominance over the strain. In addition, it is essential that the plant has good access to sunlight and that pruning favors aeration to prevent the appearance of fungi that can spoil the crop. In the event that these new strains already established do not manage to prevail over their neighbors, correct cultural practices must be carried out to favor their good implantation.

Along the same lines, throughout the second year, viticultural practices will depend on the weather and this is one of the determining factors for the development to continue to be adequate. However, as at the beginning, it is advisable to carry out tillage throughout the plantation and, especially, in the surroundings of the replaced ones. In this way it is possible to break the clods and facilitate the development of the new root system of the vines. On the other hand, optimal oxygenation of the soil is also promoted and weeds that generate competition are eliminated. It is one of the ways that have been traditionally used to avoid the use of herbicides, since their use is not recommended on young plants.

Within the plants that are placed to replace, they can be grafted plants or rootstocks without grafting to be grafted later. One of the practices used is to use rootstocks that are more vigorous than those of the original plantation so that the plants can compete with more guarantees. Above all, resistance to drought and fatigue.

In the same line of achieving the settlement of introduced plants, from Guísamo they present the three most appropriate formulas. The first and most traditional would be the already mentioned manual tillage (preparation and placement). The second would be the placement of anti-weed meshes that, in principle, are benign for crops and quite effective, or also moisturizing gels and slow-release fertilizers. Finally, it would be the use of drying herbicides that do not affect the root system of the plantation. It is the most aggressive option with the soil and the professionals of the CFEA of Guísamo add that it is not recommended at all and in no case should it be used with young plants, which are very sensitive both in the aerial part and, above all, in their root system. .

Manage crops with a long-term vision

Wine experts agree that crop management must be done from the fruit and horticultural point of view and in the long term. It should be clear that the crops in the vineyard are permanent. Increasingly, due to various incidents of an environmental nature, mechanization, phytoncides, etc. the sustainability of permanent crops is more complex.

One of the usual long-term problems are wood diseases, derived from poor agronomic practices that favor the infection of viruses, fungi and bacteria from different sources. Hence, the importance of monitoring and professionalization of the wine sector. In this aspect, professional agricultural training and research play a very important role in minimizing these negative effects that mean that plantations, increasingly, last less time for their productive potential.