LAUSR

Abstract Soil is a non-renewable environment in which, depending on the prevailing O2 conditions, two opposite processes – methanogenesis and methanotrophy - may take place. The rates of the processes may result in soil acting as a sink or a source of methane (CH4). Due to agricultural practices, heavy metals may accumulate affecting soil microbial processes. We tested the effect of cadmium (Cd) contamination on CH4 emission and uptake in three mineral soils (Eutric Cambisol, Haplic Podzol, Mollic Gleysol). Additionally, in the methanotrophy study, different soil moisture levels (pF 0; 2.2; 3.2) were studied. Based on the European annual and maximum limits, soils were polluted with cadmium in four doses (per dry soil mass): 0.048 mg Cd kg−1 (and its five-fold higher value) and 3.00 mg Cd kg−1 (and its five-fold higher value). The results showed that all tested soils produced and consumed CH4. Methane production rates were not significantly changed by the presence of the cadmium (except annual five-fold Cd dose in Podzol). In methanotrophy study, soil moisture was stronger regulator of CH4 oxidation (p