Chernozemic soils are distinguished based on the presence of thick, black or very dark, rich in humus, well-structural and base-saturated topsoil horizon, and the accumulation of secondary carbonates within soil profile. In Central Europe these soils occur in variable forms, respectively to climate gradients, position in the landscape, moisture regime, land use, and erosion/accumulation intensity. “Typical” chernozems, correlated with Calcic or Haplic Chernozems, are similarly positioned at basic classification level in the national soil classifications in Poland, Slovakia and Hungary, and in WRB. Chernozemic soils at various stages of their transformation are placed in Chernozems, Phaeozems or Kastanozems, supplied with respective qualifiers, e.g. Cambic, Luvic, Salic/Protosalic, Sodic/Protosodic etc. Some primeval Chernozems thinned by erosion may still fulfil criteria of Chernozems, but commonly are shifted to Calcisols. Soils upbuilt (aggraded) with colluvial additions may also retain their original placement in Chernozems, getting supplementary qualifier Colluvic. “Hydromorphic” chernozemic soils, in many CE systems are placed as separate soil type (“czarne ziemie” or “čiernice”) at the same level with “typical” chernozems. Classification of these soils in WRB depends on the presence of chernic horizon, depth of secondary carbonate accumulation and depth of gleyic/stagnic properties, and may vary from Gleyic/Stagnic Chernozems/Phaeozems to Mollic Gleysols/Stagnosols. Although WRB classification differs from national classifications in the concepts and priorities of classification, it provides large opportunity to reflect the spatial variability and various stages of transformation/degradation of chernozemic soils in Central Europe.
Transformational changes after 1989 were primarily caused by major social changes, including those in the economy and agriculture. Slovakia is also affect by globalization processes. The aim of this article is to characterize the changes in agricultural land use and their spatial distribution in relation to the political transformation of society after 1989, using the Dunajská Streda, Levice, Prievidza and Stará Ľubovňa districts as examples. These districts contain all individual agricultural production types in Slovakia. Changes in agricultural land use were analyzed on the basis of the total areas of land use categories for these districts between 1980 and 2010 and for municipal cadastral areas in selected districts between 2000 and 2010. Two basic indicators of changes in land use were selected for this purpose. The first was the percentage increase or decrease in individual land use categories and the second was the dominant processes in land use based on analysis of the main landscape processes. The cumulative surfaces of selected crops and their products were analyzed using a simple continuous diagram depicting the course of harvesting areas between 1980 and 2010. Crop yields were analyzed by linear regression. The tendency for disappearance of agricultural land use was confirmed in the less agriculturally active areas of Slovakia. This decrease in agricultural land use was at the expense of an increase in urban areas and in the processes of greening, forestation and water body construction.