This analysis consists of understanding the soil and subsoil in a plot by digging a pit several metres deep. This type of analysis only needs to be carried out once. It is preferable to dig soil pits on bare, resting soil, but if this is not possible, soil pits near vines are perfectly suitable. Several pits should be dug on the same plot in order to "grid" the area and better understand certain characteristics (soil types, pronounced heterogeneities, hydromorphy, etc.). This operation can be carried out by a service provider or internally if the vineyard has the correct equipment.
2.6.2.b Soil pits
Several kinds of information are of interest:
- Root system depth and the presence of, for example, cuirasse (an armour-like crust) or iron-rich clay
- Soil composition, i.e. clay / sand / silt with their different depths and thus their behaviour with regard to water and mineral retention
- The water flow system and therefore the hydric behaviour of the plot
This analysis enables a more general understanding of all the elements for a given plot and makes it possible to divide up the plot with regard to fertilisation and/or harvesting if there is a significant difference between the soil types in different parts of the plot.