Abstract
The paper considers the impact of ground sulphur (S 0 ) used as a chemical ameliorant for alkali-saline soils, as well as of sulphur with mineral and organic fertilizers, on species diversity and abundance of soil phototrophic microorganisms – algae and cyanobacteria. The research was carried out in laboratory conditions through the example of alkali soil. The alkali type is automorphic, its subtype is brown semiarid. Application of ground sulphur, as well as sulphur with mineral and organic fertilizer additives to alkali-saline soil caused considerable change in its chemical and physical-chemical properties: рН decrease, and increase in conductivity and phosphorus, potassium, magnesium, and calcium content in soil extract. Soluble carbonates and hydrocarbonates content decreased. Changes in soil properties and chemical composition effected species composition and abundance of soil algocyanoflora. 16 species, including Cyanobacteria – 10, Bacillariophyta – 4, Chlorophyta – 2, were found in the control soil. 25 species of soil microphototrophs, such as Cyanobacteria – 14, Chlorophyta – 4, Bacillariophyta – 7, were found in the soil of experiment variants. Algocyanoflora species composition of control and experiment variants remains mostly the same (64%). Application of mineral and organic additives caused growth of algocyanoflora species diversity in soil. Sulphur application contributed to microphototrophs cells increasing in number. The highest species diversity of microphototrophs found in the variant with sulfur and a complex of mineral and organic fertilizers.