Geochemical imprint and baselines in diagnostic surface (Amo) horizon as an ancillary tool in classification of Istrian soils

In accordance with the Soil Suitability Map of Croatia the soils of the Istrian peninsula represents a patchwork of different units showing both systematic and random elements in their spatial variability. A total of 40 chemical elements were used on the basis of 135 sampling sites of Amo-horizon (0-20 cm), which roughly conforms with the soil mapping units. Principally the bedrock underlying the soil cover, i.e. their lithology, exerts the dominant control over the areal disposition of the soil cover. If a suitable multivariate statistical analysis of discrimination is to be applied to these a priori defined units the result will necessarily be the same. The composition of parent material will be a prime source in development of essentially two dissimilar kind of Istrian soils: 1) mature soils developed over carbonate bedrock, which include diagnostic epipedons of polygenetic nature such as, for example, various subunits of terra rossa, and; 2) immature soils developed on soft, flysch bedrock, typically rendzinas and vertisols. Using in this manner obtained geochemical baseline ranges, an attempt is made to partition soil metal concentrations into natural and anthropogenic fractions. Also the models from both soil groups improve the comparability of element contents through correction of variable background concentrations.