Toma Shishkov, and Maria Jokova
Institute of Soil Science, Agrotechnology and Plant Protection “Nikola Poushkarov”, 1331 Sofia, Bulgaria
Shishkov, T., & Jokova, M. (2018). Characteristics of soils from the plateau of Kamen briag and the fault-block terrace of the reserve “Yailata”. Bulgarian Journal of Agricultural Science, 24(4), 581–585
Soil characteristics are result of the soil development stages and depend on the intensity and duration of weathering and soil forming processes. Investigations on local environment constituents are associated with studies on the representative soil units and on the morphological, physical, chemical and mineralogical properties of soil varieties. The paper deals with a study of the distribution along profile depth of the free (nonsilicate) forms of elements of Fe and Mn in the most representative soil units along the Northern Black Sea Coast in the region of the plateau of Kamen briag and the fault-block terrace of the reserve “Yailata” with the aim to present the intricacy of soil evolution. The paper presents results of the differences observed in specific patterns of the the content of total Fe2O3 and Al2O3, as well as in the pyrophosphate extractable free Fe and Mn forms (bound with organic matter) in Leached Chernozem (Karasoluk) and the content of the dithionite extractable free Mn and especially by the content of oxalate extractable Fe in the Fericalcareous soil. As a result, this reflects the soil colour 10YR Hues of the Leached Chernozem (Karasoluk) and 2.5YR Hues of the Fericalcareous soil. There is no correlation of the red soil color and total content of Fe2O3 neither in the soil mass nor in the clay. Obviously the red color is determined not from the total content of Fe2O3, but from its free forms Feo (oxalate), determined by the method of Tamm, and Fed (dithionite), determined by the method of Mehra-Jackson. It is established that the content of Fed is lower than that of Feo. There is a difference from the most soil of Bulgaria, in which Fed > Fee, mainly due to the features of temperature-moisture regimes and presence of carbonates.