Influence of sewage sludge on the chosen soil properties and microbiological parameters of urban grass mixtures rhizosphere

The aim of this study was to analyse the influence of municipal sewage sludge on selected microbiological parameters in the rhizosphere of lawn grass mixtures. Four experiments on the lawns along the main roads of Bialystok were founded. The factors in the experiment were three doses of sewage sludge (0 – control; 7.5 and 15 kg·m-2) and two grass mixtures (Eko and Roadside). The studied parameters were monitored twice during 2011 vegetation season by determining the total number of soil microorganisms, the total number of Gram-negative bacteria, the number of bacteria of Pseudomonas fluorescens species, the number of amylolytic and proteolytic bacteria. Sewage sludge amended to soil resulted in a change of physical-chemical properties of soil. The sewage sludge application to soil influenced significantly the number of proteolytic and Gram-negative bacteria.