Table 2
The vineyard soils from the Alcubillas site showed a heterogeneous
concentration for the elemental composition (Table 2), with Si and Ca
being the most abundant major elements followed by Al, influenced by the
parent rock. The average soil cointents in Ca were 134.4
g·kg–1 in topsoil (Ap horizons) and 161.6
g.kg–1 in subsoil (B horizons). These values (that
highlight the calcaric character of the studied soils) are higher than
the global average (15 g·kg–1, Kabata Pendias 2011
and other authors); in some case the Ca content even reached values up
to 412.7 g·kg–1. It is worth pointing out that there
are wine areas in the world with similar contents in Ca and many of
these are highly appreciated for their wines. This is the case, for
example, in the Champagne and Burgundy regions in France, Tuscany in
Italy, and La Rioja in Spain.
Iron (Fe) and potassium (K) are present at lower levels that Ca. Iron –
the average content of which in both horizons was 32.3
g·kg–1 – is necessary for the formation of
chlorophyll, the respiration process of plants and the formation of
certain proteins. The value for sulfur (S) obtained in the study area is
0.6 g·kg–1, a value below the average world
background level (0.70 g·kg–1, Kabata-Pendias 2011).
The variances in the Si and Ca values are very large, while Na, Mg, S, P
and Mn showed low variance. These variations can be explained as being
the result of soil evolution and, to a lesser extent, ploughing and
agricultural practices, as reported by Mîrlean et al. (2007). Manganese
(Mn) concentrations varied very little in the soils in the study area
(between 0.7 and 0.6 g·kg–1).