Fig. 6

Heat map and cluster analyses describing the differences in relative abundances for antibiotic-resistance genes (ARGs) in the sewage sludge and soil samples. Similarity was estimated according to the Bray–Curtis index (BC). The colour scale was set to describe lower to higher values for each group of ARGs. Unfertilized soil samples (S1, S2), fertilized soil samples (S1SL, S2SL) and sewage sludge (SL).