Zinc (Zn) plays a special role in soil ecology and fertility because it can support the growth of soil organisms or inhibit their growth depending on its concentrations. In this work, the effects of different concentrations of Zn on soil microbial communities and activities were analyzed by loading five different doses of Zn (160-6000 mu g g(-1)) into a wheat surface soil. The microbial metabolic process revealed a significant bimodal pattern at high concentrations of Zn (>1920 mu g g(-1)). This phenomenon suggested that soil microorganisms were very sensitive to zincous poisoning. A variety of soil quality properties were also measured and assessed. The results showed slower bacterial growth in soil cultures polluted with high levels of Zn. In addition, two kinds of fungi were identified by morphology and glomalin-related soil protein content in the Zn-contaminated soil. The growth of the first kind was inhibited with increase in Zn concentration. By contrast, the second kind could survive and continue to grow with increasing doses of Zn at 160-1920 mu g g(-1) and its growth began to decline with further increase in Zn concentration. Finally, the fungus could not survive at very high (6000 mu g g(-1)) Zn concentration. In this work, we conclude that soil microbial communities and activities can adapt to Zn pollution to a certain extent. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.