Figure 3.

Effect of soil contamination with cadmium (Cd²⁺) and cobalt (Co²⁺) on the colony diversity index (EP) of (a) organotrophic bacteria (Org), (b) actinomycetes (Act) and (c) fungi (Fun). C0—uncontaminated soil, Cd—cadmium ion, Co—cobalt ion. C0—uncontaminated soil, Cd—cadmium ion, Co—cobalt ion. C—control, M—molecular sieve, H—halloysite, S—sepiolite, E—expanded clay, B—biochar, Z—zeolite. Homogeneous groups denoted with letters (a–f) were calculated separately for each pair of independent variables.