The soil where the vine is planted is one of the vectors of quality of the wines produced by that vineyard. In our Rioja Denomination of Origin, soils are classified into three main groups: calcareous clay soils, ferrous clay soils and alluvial soils. It can be said that calcareous clay soils favor wines with «body» and a perception of a higher volume in the mouth. Ferrous clay soils (red soils) produce medium-bodied wines, while alluvial soils produce light-bodied wines.
Our winery and vineyards are located in the so-called Rioja Alavesa. Out of the three Rioja areas, this is the one with more special features. The region has a barely modified landscape thanks to the abrupt topography, typical from Somontano and Sonsierra—with a southern orientation and located at the mountain’s feet. Unlike other wine-growing areas, the Rioja Alavesa is one of the few main vineyards in the world that is mostly located in small plots, both because of its particular orography and because it does not have the massive plot concentration seen in other regions.
Bodegas Fos’ vineyards are located in the Rioja Alavesa region, between 400 and 700 meters above sea level. Our vineyards have an almost absolute predominance of calcareous clay soils (brown soils) and basic pH. These soils developed on Neogene and Miocene marls and clays due to colluvial (mainly from the mountains) and alluvial formation. Some developed on sandstone plains and are shallow, flat, stony, limy, and loamy textured. Others are located on slopes, developed on marls; these are moderately deep, with slight slopes and few stones, calcareous and fine loam textured.
Calcisol, Cambisol and Fluvisol
According to the international soil classification, we have:
Haplic calcisol (calcisol = calcareous). Profile type ABC. The surface horizon is pale and ochric; the B horizon is cambic or argic, and may even present vertic properties. There is always an accumulation of carbonates in the C horizon.
There are also calcareous cambisols, characterized by a calcareous content over 25%, very poor in organic matter, with little accumulation of clay in the B and lower horizons, and under which there is a marly rock that allows easy penetration of the roots. It is yellow in color. These soils are well drained and very suitable for vineyard growing but not very fertile.
Profile type ABC. The B horizon is characterized by a weak to moderate alteration of the original material; and by the absence of significant quantities of clay, organic matter and iron and aluminum compounds. It is an illuvial horizon. There are also some small dotted spots in the ferrous clay soils’ area (petric calcisols or calcareous regosols) that are formed on sandstones, limonites, clays and marls. They contain less than 25% of limestone and a high proportion of clays, resulting in reddish-colored soils—usually with an excess of aluminum in their composition.
Alluvial soils (fluvisols) are also present in our area (terraces formed by the Ebro River). These are the most fertile and the most suitable for light wines. They are especially good for horticulture, as their flatness favors the accumulation of soil moisture.
The term fluvisol derives from the Latin word «fluvius» (river), referring to the fact that these soils are found on top of alluvial deposits. The original material is made up of deposits—predominantly recent ones—of fluvial, lacustrine, or marine origins. The profile type is AC, with clear stratification that makes it difficult to differentiate the horizons, although a very notable Ah horizon is commonly found. Redoxorphic traits are common, especially in the lower part of the profile.
CALCAREOUS SOIL – CALCIUM
Much is said about the ideal habitat for a vine. It is well known that calcium greatly influences the use of other nutrients, so its functions are directly related to the grape quality and the wine obtained. Calcium has a significant influence on the plant’s health, both in the root system and in the aerial part, and it is related to the formation of the rhizosphere and the microbiota of the soil.
In addition, it defines the soil’s structure and its capacity to supply water to the plant—especially at veraison, the moment of greatest water consumption. It is the only way to eliminate clays, by helping to combat toxicity due to aluminum excess in the soil. It is the only element capable of eliminating excess sodium from the root bulb
It is crucial for meristem growth and for the growth and proper functioning of radical apexes. It is a middle layer component, with a cementitious function as a calcium pectate. It prevents cell membrane damages by preventing the escape of intracellular substances. It seems to act by modulating the action of plant hormones, regulating germination, growth and ageing.
|CE mS/cm (H2O)||60||61||86||86||180|
|Organic Matter %||1.5||0.8||0.5|
|Ememen. Coarse %|
|Coarse sand %|
|Fine sand %|
|Total amount of sand %||60.3||74.7||72||76||73.3|
|Soil Adsorption Complex|