Impacts of Norway spruce (Picea abies l., h. karst.) stands on soil in continental Croatia

Abstract

A quantitative analysis of pedo-physiological indicators aimed at determining changes in the soil attributable to the effects of spruce plantations was done. The study was conducted at eight sites in central and north-western Croatia where spruce plantations were planted in the late 20th century. At each site, a pedological profile was opened within the spruce plantation and the endo-morphological parameters of the soil were determined. Composite soil samples from two depths (0-10 cm and 10-20 cm) and from the forest floor were taken in the spruce plantation and compared with samples taken at plots covered by natural vegetation (natural stands) located in the surroundings. The following pedo-physiographic indicators were measured on the collected soil samples: quantity of forest floor, particle size distribution of soil, pH values in H2O and in CaCl2 aqueous solution (concentration 0.01 mol dm-3), content of Corg, content of Ntot and content of bioavailable nutrients (using the Mehlich III method). The results showed that the forest floor had a higher mass in the spruce plantations than in natural stands. The mineral soil showed clear trends of influence of the spruce plantations on soil in terms of reduced pH values. Most plots in the spruce plantations showed a lower nitrogen content in the soil, a higher C/N ratio and lower content of bioavailable phosphorus. This study provides an insight into the amelioration effects of spruce plantations on soil, and represent a reliable basis for decision-making in planning specific interventions in terrestrial ecosystems, such as the establishment of new forest plantations.