Evidence and mineralogical and physico-chemical properties of chernozem and chernozem-like soils in Croatia

The aim was to determine possible local differences between the parent materials of recent leoss-derived soils in eastern Croatia (Dalj, Zmajevac). Furthermore, it highlights the existence of chernozem and chernozem-like soils in Croatia and describes their basic physical, chemical and mineral properties. For this purpose, two soil profiles (P-3 and P-6) south of the Dalj settlement and one soil profile (P-10) near the Zmajevac settlement were excavated. The investigation included a detailed pedological analysis, a modal analysis of the heavy and light mineral fraction and a mineralogical analysis of bulk samples (the < 2 mm fraction) and the fraction < 2 μm. By comparing the obtained results with the criteria of the Croatian Soil Classification and the World Reference Base for Soil Resources, the soil profiles P-3 and P-6 can be defined as Chernozem on Loess or Hortic Calcic chernozem (Epiloamic, Endosiltic, Aric, Humic). The systematic unit for profile P-10 was defined as Rendzina according to the Croatian Soil Classification or Calcic Chernozem (Siltic) according to the WRB. Based on the results of the pedological analysis of the soil profile horizons, a gradual degradation of the chernozem was observed as a result of anthropogenic influence, but also due to recent climate change. The degradation is particularly evident in the form of a reduction in organic matter and the relocation of carbonates from the surface to deeper zones. Due to the increasing degree of weathering caused by recent climate changes, some differences in the mineralogical composition of the studied soils were also observed. The progressive degradation of the chernozem due to the effects of recent weathering processes is indicated mainly by the presence of goethite in the fraction < 2 μm as a weathering product of iron minerals (magnetite, pyroxenes…). Although the parent material of all three profiles is loess sediments, the reason why the soil material of profile P-10 has not developed a chernic horizon is the constant contribution of aeolian material and a short period of exposure to pedogenetic processes.