Copper (Cu) and zinc (Zn)
Copper is also one of the most widely studied elements in wine-growing
regions because the treatment and prevention of vine downy mildew is
commonly carried out using the Bordeaux mixture (Ca(OH)2+ CuSO4). However, copper becomes toxic to plants and
some micro-organisms when it is present at high levels in soils as it
disrupts nutrient-cycling and inhibits the mineralisation of essential
nutrients.
In the soils under discussion here, copper was present in an acceptable
medium level (Table 3), i.e., between 25.0 mg·kg–1(topsoil) and 23.7 mg·kg–1 (subsoil). The world
average level in soil is 30 mg·kg–1 (from 2 to 250
mg·kg–1, Adriano 2001) and the normal variation in
soils is between 5 mg·kg–1 and 50
mg·kg–1 (Bloemen et al. 1995). A mean value of 35.4
mg·kg–1 has been determined in Spain (Peris et al.
2007), 24 mg·kg–1 (from 1 to 111
mg·kg–1) in Portugal (Reis et al. 2007), 227
mg·kg–1 in France for the deep horizon (Chopin et al.
2008), while in Brazil the content is in the range from 50.1
mg·kg–1 (20 years) to 2197 mg·kg–1(100 years) (Mîrlean et al. 2007). The pedogeochemical baseline level
for Castilla-La Mancha is 10.3 mg·kg–1 (Jiménez-
Ballesta et al. 2010).
The average contents in Zn (Table 3) are 47.4 mg·kg–1(topsoil) and 43.6 mg·kg–1 (subsoil). According to
other authors the values for Zn range between 10
mg·kg–1 and 300 mg·kg–1 (Adriano
2001), with a world soil average of 50 mg·kg–1, so
contamination is not evident for this element. In Castellon (Spain) the
average value is 76.8 mg·kg–1 (Peris et al. 2007); in
the Champagne region of France (Chopin et al. 2008) the values range
from 318 mg·kg–1 in the topsoil to 208
mg·kg–1 in the deep horizon, with 75
mg·kg–1 as median; and in Portugal (Reis et al. 2007)
a minimum value of 14 mg·kg–1 and a maximum value of
344 mg·kg–1 were determined for vineyard areas.
Finally, the pedogeochemical baseline level for Castilla-La Mancha
(Central Spain) is 35.7 mg·kg–1 (Jiménez Ballesta et
al. 2010). Increased concentrations of Zn and Cu in soils under the
long-term production of grapevine have been recorded in numerous studies
(Romić and Romić 2003; Fishel 2014; Tóth et al. 2016).