Soil solution composition in forest soils of sierra de gata mountains, central-western spain: Relationship with soil water content

Abstract

Nutrient ion concentrations in soil water were assessed in three deciduous forests in the Sierra de Cata Mountains, central‐western Spain, with annual precipitation ranging between 720 and 1,580 mm. Soil solutions were obtained at incremental depths from 15 to 110 cm with tension lysimeters and analyzed for pH, electrolytic conductivity (EC), dissolved organic carbon, soluble Si and Al components, Fe3+, Cu2+, Mn2+, Zn2+, Na+, K+, Ca2+, Mg2+, Cl−, SO4 2‐, and NO‐3. In general, ion concentrations and pH decreased with depth (from pH 6.5 to 5.5) and EC from 50 to 25 μS cm−1. At the driest forest site (Fuenteguinaldo), the highest EC values were at the profile surface, probably due to a lower degree of leaching and increased capillary action, as compared with profiles from forests with a higher annual precipitation. Soil water content was correlated with soil solution composition, showing a strong interdependence. The ionic composition of soil water in the three Cambisols, however, did not reflect the differences of annual precipitation.