Soils over Calcareous Rocks in Golo Burdo Mountain

The paper deals with calcareous soils in Golo Bardo Mountain in western Bulgaria. Until now no significant studies have been made for the soils of Golo Bardo Mountain. Our goal was to give assess data for their soil features, characteristics, main diagnostic indicators and properties in order to define the soil formation processes, as well as their complete morphological description. Eight soil profiles were studied in different parts of the mountain. Due to the carbonate soil-forming rocks, the leaching processes in these soils are extremely weak and it is usually difficult to distinguish the individual genetic horizons. In relation to the soil-forming carbonate rocks in the area, we distinguish two main soil units. The studied soils are Leptosols or Phaeozems with good fine-granular structure, dark humus horizon (mollic) and shallow soil profile Ak-ACk-CRk, lying on hard or weathered carbonate rock. In the studied mountain area with different elevation, the surface mollic horizon is usually shallower and very often eroded with fragments from calcareous rock. The soils are well stocked with organic matter. The amount of organic carbon in the surface A horizon varied from 7.4 % to 2.8%. The calcium dominates in exchange capacity of the soil over all other cations. There is no exchange acidity in these soils, except small amounts in the soil surface and in litter. The content of carbonates is an important soil-forming feature of these soils.