To Örebro University

Microbial community patterns and their potential substrate utilization were examined to test for sustainability in metal polluted soil. The acid mine drainage (AMD) influenced test field was characterized for total soil respiration and the functional diversity of the soil bacterial communities using BIOLOG EcoPlate assays. Inoculation with the mycorrhizal fungus Rhizophagus irregularis and two streptomycetes led to an altered metabolic diversity and soil vitality, with cell numbers increased by one to three orders of magnitude. The change in metabolic activity was stable even after one winter with severe frost periods. The inoculation thus resulted in enhanced microbial activities. This vitalization resulted in enhanced formation of soil organic matter which, in turn, can sustain higher microbial cell numbers. We therefore conclude that inoculation with indigenous bacteria and a versatile mycorrhizal fungus results in improved vitality suitable for plant growth at heavy metal polluted soils. This holds a huge potential for the remediation of the legacies of mining activities and allows for land-use strategies on metal contaminated sites the world-over.