Regional scale effects of base cation fertilization on Norway spruce and European beech stands situated on acid brown soils: soil and foliar chemistry

Ten experiments were installed on acid soils in different ecoclimatic condi tions of the Belgian Ardenne. Soil pH, exchangeable cations and P contents as well as foliar nutrient concentrations were monitored 1 and 3 years foll owing the application of either (1) 3 t ha(-1) of a dolomitic limestone or (2) 3 t ha(-1) of a dolomitic limestone plus different amounts of P (0-800 kg natural phosphate) and/or K (0-250 kg K2SO4). Dolomite rapidly increased Ca and Mg concentrations in the 0-10 cm soil layer and in the tree leaves. After three years, exchangeable Al was significantly lower in the first so il layer but it still represented more than 50% of the exchangeable cations . Mean pH increase in the 0-10 cm layer was less than 0.5 pH units. Dolomit e alone tended to reduce mean K concentrations in the soils and/or leaves o f the beech stands. The addition of potassium sulphate to dolomite generall y increased the soil and foliar K contents in the spruce stands contrary to the beech stands. It also tended to increase the resaturation of the excha nge complex with Ca and Mg ions. The effects of natural phosphate addition were restricted to a slight increase of P foliar concentrations. The B foli ar concentrations were reduced by both treatments, whereas Zn concentration s increased significantly. The between stands variability of soil and folia ge chemical properties was important but did not influence the effects of t he treatments.