Spatial variability of some soil properties in pure Abies and Abies – Pinus sylvestris mixed stands

Use of geostatistical methods to analyze soil variation when systematic variability is the case provides great advantages over classical statistical techniques. In this study, spatial variability of some soil properties were compared in 0-15 and 15-30 cm depth of soils on a pure stand of Abies (Abies nordmanniana subsp. bormülleriana mattf.) and on a mixed stand of Abies and (Pinus sylvestris L.) In total 428 soil samples were taken based irregular grid system from 210x240 study pasels located in each of stand. Experimental semivariograms for soil properties were modelled and ordinary kriging interpolations were made. In general, exponential model described the experimental semivariograms for soil attributes most properly in the mixed stand and spherical model in the pure stand. Nugget effect ranged from 0.03% to 100% and it was generally high in both of the stands, indicating high short-range variability of soil attributes. Geostatistical range (Ao) was between 4.30 m to 167.03 m and no consistent differences occurred in Ao neither between stands nor soil depths. Performance of kriging interpolations was generally poor due to high short-range variation of soil properties, and this should be considered in determination of sampling intervals in similar prospective studies.