CONTENT OF HUMUS AND SOIL pH OF THE SOILS FORMED UPON LIMESTONES AND DOLOMITES

Abstract

The soils formed on limestones and dolomites have been examined in different locations on the territory of the Republic of Macedonia. The filed researches have been performed in the course of 2010, 2011 and 2012, during which 52 basic pedological profiles were excavated, of which 34 were Rendzic Leptosol, 13 were Chromic Leptic Luvisol on hard limestones and 5 were profiles of Rhodic Leptic Luvisol on hard limestones. These soils are characterized with a profile type O-A-R; A-R; A-(B)rz-R. Seventy eight soil samples were taken for laboratory analyses. The field researches carried out in accordance with the accepted methodology in our country.The pH (reaction) of the soil solution was electrometrically determined with a glass electrode in water suspension and in suspension of 1M KCl. The humus content was determined on the basis of the carbon organic C according the Tyurin method, modified by Simakov. Rendzic Leptosols are characterized with the highest content of humus in relation to the other soils formed on limestone and dolomite. The subtype organogenic Rendzic Leptosols has highest mean value (19.47 %). The content of humus in the Amo horizon amounts to 8.50 % on average, and in the cambic horizon (B)rz 5.18 %. In the Rhodic Leptic Luvisol on hard limestones, the average content of humus in the Amo horizon amounts to 5.33 %, and in the cambic horizon B(rz) it amounts to 2.13 %. pH in H2O in the subtype organogenic Rendzic Leptosols is an average of 6.99, average value of (6.93) belong to the organomineral Rendzic Leptosols. In the Amo horizon with the cambic Rendzic Leptosols pH in H2O is 6.12 and in the cambic horizon (B)rz, pH is 6.68. In Chromic Leptic Luvisols on hard limestones there is decarbonization and weak acidification, due to which the soil solution is weak acidified and in the Amo horizon and (B)rz the average value of pH in H2O is 6.63. In the Rhodic Leptic Luvisol on hard limestones the average pH in H2O in the humus-accumulative Amo horizon is 6.94 and in the cambic horizon (B)rz pH in H2O is 6.72