MICROBIOLOGICAL PROPERTIES OF REKULTISOL UNDER DIFFERENT CULTURES AT STANARI COAL MINE

Sažetak

UDK 631.427.1(497.6)

This paper studied the number of physiological and systematic groups of microorganisms in rekultisol under the different cultures at Stanari Coal Mine, and in variants of rekultisol where mineral fertilization and calcification were applied and in variants of rekultisol where only mineral fertilization was applied. The trial was set in the field conditions at the location of the internal part of overburden deposition site, near open pit Raskovac which is the part of Stanari coal mine. Mineral fertilizers were used as starter fertilizer and supplementary nutrition in the amount of 100-140 kg/ha of N and 40-60 kg/ha P2O5 and K2O and calcification was completed by adding 4 t/ha CaCO3. Microbiological analysis of the rekultisol determined the total number of bacteria, Azotobacter sp., ammonifiers, oligonitrophyls, actinomycetes and fungi. The aim of the research is to determine microbiological properties of rekultisol under small grains, potatoes, and grass-clover mixture at “Stanari” coal mine as well as to determine the effect of mineral fertilizers and calcification on the number of microorganisms in the rekultisol under different cultures. The total number of bacteria, oligonitrophyls, sporogenic ammonifiers, Azotobacter sp. and actinomycetes was higher in rekultisol under all of the tested cultures in the variant fertilizers + CaCO3 comparing to the variant without CaCO3, while the number of ammonifiers and fungi in rekultisol under all of the tested cultures was higher in the variant without CaCO3 in relation to the variant mineral fertilizers + CaCO3. In rekultisol under grass-clover mixture, higher total number of bacteria, oligonitrophyls and fungi was recorded in both tested variants, in relation to their number in rekultisol under potatoes and small grains. The number of actinomycetes was higher in rekultisol under potato in both variants, in relation to the number of actinomycetes in rekultisol under small grains and grass clover mixture. In rekultisol under small grains in variant mineral fertilizers + CaCO3 number of ammonifiers was the lowest (182 x 10⁴g^-1 absolutely dry soil), while the highest number of ammonifiers was recorded in rekultisol under grass-clover mixture in the variant without CaCO3 (1778 x 10⁴g^-1 absolutely dry soil). Azotobacter sp. count was lowest in rekultisol under grass clover variant without CaCO3 (68 x 10²g^-1 absolutely dry soil), while the highest Azotobacter sp. count was recorded in rekultisol under small grains in the variant with fertilizers + CaCO3 (123 x 10²g^-1 absolutely dry soil).