10 facts you should know about cover crops in vineyards

What is a cover crop? What are its advantages? its drawbacks? Which cover species should be chosen? What factors should be taken into account for its management?…

Cover crops are a complex subject that raises many questions, so much so that it is sometimes difficult to find one’s way around.

Here are 10 facts you need to know about cover crops in vineyards :

1. Cover crops are plants cover the soil between and under taller crops

Cover crops can be found between and under the rows of at the foot of a vertical crop (vineyards, orchards..). They can be natural or sown, temporary or permanent, planted in all rows or not. They represent an alternative to chemical weeding and tillage.

This technique is not new, as the Romans were already using it 2000 years ago.

Indeed, until the 1930s, this method of maintaining vineyard soils was considered a good viticultural practice, with positive effects on soil.

Later, the development of mineral fertilizers, mechanization, and an increased awareness of the nutrient and water competition between “grass” and vines led to extensive weeding in vineyards. Since the 1970s, chemical weed control has been adopted by the vast majority of vineyards in France.

2. Cover crops favor life in the soil

Cover crops are an important source of organic matter that encourages life in the soil. They create biotopes favoring the formation of humus and the development of microbial ecosystems.

3. Cover crops protect the soil from erosion and limit the transfer of pesticides

In addition, studies show that cover crops can limit the development of Botrytis, or “grey rot”, a fungal disease that is favored by humidity.  As three quarters of phytosanitary applications are intended to control fungal diseases, this has indirect effects on the amount of pesticides that are used.

4. . Cover crops create competition

Cover crops create competition for water and nutrients between the plant cover and the vine. This competition is strongly influenced by climate – in particular by sunshine and rainfall – and must be controlled and adapted to the desired objectives. If it is too strong, the vine will become water stressed and will not absorb the appropriate amount of nitrogen.

The competition caused by cover crops occurs during the vegetative season of grapevine and during berry ripening. Thus, it begins at bud break and becomes more pronounced at flowering. During the vegetative rest period (autumn and winter), there is no competition between cover crops and grapevine.

If competition is too important, it can result in grapevine stress. Therefore, to control competition, it is possible to adjust the width of the grass cover or to irrigate. Be careful, however: to be effective, these measures must be taken at the right time.

5. Cover crops are not recommended for young vines

Because of water and nutrient competition, the French Institute of Vine and Wine (IFV) advises against growing cover crops in young vineyards that are less than 3 years old. Plants are not sufficiently developed to draw water and nutrients from the soil deep layers.

With the exception of particularly vigorous plots, cover crops should not be considered before the 4th or 5th year. However, grass strips can be planted around the plot to limit erosion.

6. Cover crops help to control vine vigor

Cover crop can be used to limit problems related to excessive plant vigour. Water and nutrient competition results in a reduction in vine vigour and yields. By controlling cover crops, winegrowers can control this balance, to improve the quality of their wines.

7. Cover crops can improve wine quality

Cover crops can affect berry composition. The nitrogen content of the grapes and their ripening are indeed modified by the competition between the plant cover and the vine. Cover crops have therefore an impact on the quality of wine: aromas, body, degree of alcohol, structure, etc. The olfactory quality of pinot-type wines improves, for example, with an increase in nitrogen concentration.

 

8. The effect of cover crops depends on the species composing them

Different types of cover crops will have very different effect on vines. For this reason, the choice of cover crop species must be accurate :  winegrowers must take into account the wine production objectives, soil structure,  vigor, berry quality, etc. The most important factor for defining the species to be planted is the desired or acceptable competition level in a given plot or vineyard. The other elements then help to refine the choice of species.

The species that are the least competitive for grapevines are legumes and grasses. Their cycle ends in May, so they disappear during the summer season, which avoids any competition for water during the hottest periods.

Finally, the possibility of a natural, spontaneous grass cover should not be neglected. This is often the simplest (and least expensive) option. The species naturally growing in the plots are already adapted to their climate and soil structure. Moreover, they are easier to destroy a strip of  planted grass, which is a significant advantage in managing competition.

10. Cover crops can be managed using digital tools

Some winegrowers give up on the benefits of cover crops to avoid water competition, even though a controlled competition could be sustainable for grapevines.Indeed , cover crops can be now managed based on precise information concerning the water status of  plots.

In order to facilitate the water and nitrogen management of crops, ITK has developed a smart digital solution: Vintel. The Decision Support System (DSS) Vintel® helps to manage irrigation and nitrogen fertilization in real time according to vine water and nitrogen needs. This solution provides winegrowers with precise knowledge of the water and nitrogen status of the plots, for a better management of the vineyard

In addition, for regions where irrigation is possible, Vintel provides irrigation recommendations adapted to each plot and target wine profile, based on agro-environmental and artificial intelligence models. This allows yield optimization and managing berry quality, plot selection, water management, etc.

In short, with Vintel, you have a real-time view of the water and nitrogen status of your vines. Want to know more? Contact-us !