In Cornas, the surface soil layer is dominated by decomposed granite what we call here "gore". This very crumbly rock is present everywhere in the vineyard in different percentages and at a variable stage of decomposition, which gives the soil a draining character due to the presence of more or less coarse sands. At depth, it is also the stage of decomposition of this rock that will determine the capacity of the roots to get the water and nutrients that the vine needs.
To the north of the vineyard, in the district of Chaillot, there are present limestone deposits and a rock originated from them, called "chailles". In this rock siliceous elements and carbonated sedimentary rocks have mixed. It originates from the erosion of a compact limestone massif, the Massif des Arlettes, which forms the border with St Joseph.
In St Péray, a neighbouring commune of Cornas, we can also found granite, granite is found but , above all, soils are made up of limestone scree associated with loess (carbonate rocks).
Concerning the management of these soils: we have noticed that since the interruption of chemical weed control and the resumption of surface tillage, we almost do not have erosion problems. The presence of pruning woods on the soil, natural grass cover, better biological activity of the soil, are all the factors that encourage water penetration or limit its runoff in the event of heavy rainfall. Thus, our vines remine grassed in the winter, the superficial mecanical weed removal that we can do in the autumn is aimed mainly to bury the compost. This operation is carried out with a winch on the slopes, by animal traction or with the help of a small tracktor in the lower slopes.
The difficulty for us, which is confirmed, with three years of high heat and water deficit, is the low yield on the slopes, but also a high mortality of young plants.