In a laboratory incubation study, the effect of select heavy metals
on methane (CH4) oxidation in two rice soils was investigated under
two moisture regimes. Heavy metals differed in their effect on CH4
oxidation in both soils under the two water regimes. Cr significantly
inhibited CH4 oxidation in the alluvial soil at 60% moisture holding
capacity, while Cu stimulated the process. On the contrary, Zn
inhibited CH4 oxidation in both alluvial and laterite soils only under
flooded conditions. Application of rice straw alleviated the
inhibitory effect of heavy metals on CH4 oxidation and CO2
production. Inhibition of CH4 oxidation in the alluvial soil was
related to the methanotrophic bacterial population in Cr- and Znamended
alluvial soil