2.6.3.a Is it necessary to lime this year?

What are the consequences of soil acidity on vine development?

Acidification occurs naturally due to the soil's biological and pedological activity and the leaching of cations.
Vines do not suffer from acidity itself but rather from the consequences of acidification. This causes a decrease in biological activity and therefore little evolution of organic matter and mineralisation, reduced structural stability and the leaching of mineral elements, which further increases acidity and results in a decrease in S/CEC. Acidity plays a crucial role in the assimilation of the elements which are more or less available depending on the pH.
Finally, soil acidification induces the dissolution of certain metals that can create toxicity (Al3+, Cu2+, etc.). It is important to consider the acid-base soil status before that of the organic matter since it strongly influences mineralisation and organic matter decomposition.

Which is required: maintenance or corrective liming?

There are two types of liming: corrective liming, suited to basic fertilisation before planting or to plots suffering from significant acidification, and maintenance liming with smaller quantities allowing the desired pH and S/CEC levels to be maintained.

Is the soil acidic?

Soil acidity is measured in a number of ways, the most important of which is the soil water pH. The ideal pH is between 6 and 8 depending on the soil type. It is generally accepted that soil with a pH under 6.5 is at risk, and the objective is usually to be above 7. Below 6, corrective liming is recommended.
In order to control the pH, the liming technique is used. This consists of adding lime composed of either quicklime (calcium oxide (CaO)) or magnesium lime (MgO).

Does the soil's cation exchange capacity need to be improved?

Liming also helps to control the saturation of the soil's CEC by adding Ca2+ ions and limiting the solubilisation of certain metals. The S/CEC should be at least 80% but this strongly depends on the soil pH. At a pH higher than 7, the S/CEC should be above 100%.
The soil analysis also gives details of the elements that make up the CEC, which makes it possible to make a more accurate choice regarding the addition of lime or organic soil improvers. If a lack of magnesium is observed, magnesium oxide can be used instead of calcium oxide.