Climate and soilThe climate of the region presents Mediterranean characteristicsalthough with some Atlantic influence. The average monthly temperaturesof the climatological normal 1971–2000 varied between 21.3 °C(July) and 4.4 °C (January), with the average annual temperature of12.3 °C. The average monthly precipitation varied between 18.4mm(August) and 118.6mm (December) with an annual total of 758.3 mm.Climate records observed during the experimental period at the meteorologicalstation of the Santa Apolónia farm, barely 200m from theplace where the experiments were conducted, are shown in Fig. 1.The soil used in the pot experiment was collected in the plot wherethe field trial was carried out. Selected properties of a composite sample of that soil collected in the 0–20 cm layer are shown in Table 1.