Effects of Different Planting Pattern on Soil Microbial Population and Enzyme Activities in Lead Contaminated Soil

To analyze the remediation effects of different planting patterns on lead contaminated soil, a pot experiment was conducted to study rhizos phere and non-rhizos phere microbial biomass, soil enzymic activity and soil physical and chemical properties of 4 plants(Trifolium repens, Salvia splendens, Callistephus chinensis, Iris tectorum) of single or mixture inoculation. The results showed that the microbial biomass, soil enzymic activity, soil repirati and organic matter indexes always showed the rhizosphere > the non-rhizosphere > the control, mixed planting > monoculture > the control. The pH released that the control > the non-rhizosphere > the rhizosphere, the control > monoculture > mixed planting. The electrical conductivity and redox potential released that the non-rhizosphere > the rhizosphere, monoculture > mixed planting. While the Pb²⁺ content showed that the control > the rhizosphere > the non-rhizosphere, the control > mixed planting > monoculture. Meanwhile, the effects of lead pollution on soil enzymic activity with bacteria were the greatest, followed by fungi and actinomycetes affected the lowest. And the effects of lead pollution on soil physical and chemical properties with bacteria were the greatest, followed by fungi and actinomycetes affected the lowest. These facts showed that single and mixing planting pattern could alleviate the stress caused by Pb pollution, and mixed planting could improve the extent of soil heath and soil microbe diversity better than monoculture, and Trifolium repens intercropped with Iris tectorum was superior to those of other planting patterns.