EVALUATION OF ORGANIC AMENDMENTS EFFECTS ON SOIL MICROORGANISMS AND ENZYMATIC ACTIVITIES OF DEGRADED CHERNOZEM

Microbiological and enzymatic properties of the long term stored municipal sewage sludge from 11 cities of the Republic of Moldova were investigated in connection with the problem of its utilization. The microbial biomass content in the sewage sludge fluctuated from 0.32 to 6.72 mg C g-1 waste, ratio between microbial and organic carbon content ? from 0.70% to 5.09%, coli-titer index from >0.1 to 0.0001 respectively. As a result of keeping wastes and mineralization processes intensification, organic carbon, microbial biomass and enzymatic activity reduced. Microbiological and biochemical parameters depended on storage duration of wastes and organic matter content. The correlation coefficient between organic carbon content and microbial biomass constituted 0.74, catalase activity ? 0.68. Using of the municipal sewage sludge as a fertilizer for reducing of the soil degradation is possible only after the preliminary composting in the combination with sugar industry waste materials (sugar lime) and manure. As a result of composting wastes sanitary indicators were improved. Organic amendments ramped up microbiological and enzymatic properties of degraded chernozem. Wastes amended soil showed a significant increase in the microbial biomass, enzyme activities and the humus content in 12 years after the application of composts.