Cluster analysis revealed high similarity of bacterial populations located in the sand fractions of all treatments; only the
community structure of the treatment that received SS was not represented in that cluster (Fig. 2). The cluster that comprised sand microbial communities also included the bacteria found in the silt fraction of the treatment without nitrogen application.The second cluster comprised bacterial communities inhabiting the silt and clay fractions. Bacterial communities of
the SS treatment were quite distinct compared to other treatments and showed high similarities in the silt and clay fractions.