MECHANICAL COMPOSITION OF THE SOILS FORMED ON LIMESTONES AND DOLOMITES IN THE REPUBLIC OF MACEDONIA

Abstract

The paper presents results from the research of the influence of the parent material on the mechanical compo-sition of calcomelanosols, calcocambisols and terra rossa. The contents of the fine soil separates in the calcomelano-sols vary depending on the subtype. The physical sand fraction (coarse sand + fine sand) in the Amo horizon amounts 44.81% in the organomineral calcomelanosols, 40.13% in the organogenic and brownised calcomelanosols 36.52%. In the (B)rz horizon in the brownised calcomelanosols it amounts 32.64%. The content of clay + silt or physical clay in the Amo horizon amounts 55.19% in the organomineral calcomelanosols, 59.87% in the organogenic and the high-est content is in the brownised calcomelanosols 63.48%. The average value of this fraction in the horizon (B)rz in the brownised calcomelanosols amounts 67.36%. In the calcocambisols the average content of the fraction physical sand in the Amo horizon amounts 33.43%, and in the cambic horizon (B)rz 22.50%. In the terra rossa the fraction physical clay is represented with a greater percentage related to the physical sand fraction. In the Amo horizon, in the physical clay fraction, the clay fraction is predominant, average 43.08%, and 52.13% in the cambic horizon, and 24.90% in the Amo horizon and 19.37% in the (B)rz horizon for the silt fraction. From a research soils 36% of the soils are formed on massive limestone, 13% are formed on dolomitic limestone and bituminous marbles, 16% on plate (flat) limestone, 10% on dolomitic marbles and 12% on laminated (plate) dolomite and calcite.