Microbial Population and Enzymatic Activities in Soil Contaminated with Heavy Metals as Influenced by Arbuscular Mycorrhizal Fungi (AMF) Species

Abstract

Heavy metal contamination in soil poses a significant threat to soil microbial diversity and enzymatic functioning, which are critical for ecosystem sustainability. This study examined how different Arbuscular Mycorrhizal Fungi (AMF) species influence microbial populations and enzyme activities in soils contaminated with heavy metals (cadmium and lead). A greenhouse pot experiment was set up in a Completely Randomized Design (CRD) with treatments including two AMF species (Glomus mosseae and Rhizophagus irregularis), two heavy metals (Cd and Pb) at two concentration levels, and a control. Results indicated that AMF inoculation significantly increased total bacteria count, fungi count, and actinomycete populations in contaminated soils compared to uninoculated controls. Enzyme activities including urease, phosphatase and dehydrogenase were markedly higher in AMF-treated soils. Rhizophagus irregularis generally performed better than Glomus mosseae in maintaining microbial populations and enzyme activities under heavy metal stress. The findings suggest that AMF inoculation is a viable bioremediation strategy for restoring soil biological activity in heavy metal-contaminated agricultural soils.