Table 1 summarizes physical–chemical properties of the studied
soils. The pH of all soil samples was similar among depths, ranging
between 4.5 and 5.8 for 0–10 cm layer and between 4.4 and 5.7 for
10–20 cm layer. These values are consistent with previous studies that
evidenced the slightly acidic character of most of the Portuguese soil
(Inácio et al., 2008). Furthermore, the pH range is comparable to that
reported by Reis et al. (2009) for agricultural soils of the same region.
The soil organic carbon content ranged from 1.1% to 6.4% for the
0–10 cm depth although only four samples showed values above 3%.
For the 10–20 cm depth, organic carbon values were relatively low