Effect Of Cd On Soil Microbial Diversity In Purple Soil And Alluvium Soil

The effects of Cadmium on soil microbial amount and biomass,soil microbial activities(soil respiration,sucrase,urease,dehydrogenase,neutral phosphatase,alkaline phosphatase,acid phosphatase) and microbial population structure were studied by pot experiment.In order to more fully understand Cadmium effects on soil microbial and to provide certain scientific theoretical foundation of r contamination control.Both of Cd contamination and soil type has a significaht effect on amount of soil microbial(bacteria,fungi,actinomycetes),soil respiration and amounts and activities of urease and three type of phosphatases;additionally,there is an interaction between Cd and soil type which also have a significant effect on those character.No significant effect on activities of sucrase and dehydrogenase and interaction between Cd and soil type was obtained.Cd contamination and planting density showed that an significant effect on amount of soil bacteria and activities of sucrase,neutral phosphatase,alkaline phosphatase,acid phosphatase;additionally,there is an interaction between Cd and planting density which also have a significant effect on those character.Cd contamination and planting density also have an significant influence of amount of soil fungi,activities of urease,interaction was not obtained.Planting density has no significant influence to amount of actinomycetes, soil respiration and activities of dehydrogenase.Cd treatment stimulated the growth and increased the diversity of bacteria in purple soil.In alluvium soil system,the change of bacteria community structure was smaller than that in purple soil system.Planting density was an important factor to affect bacteria community in soil when the density was betweenâ… andâ…¡.While when the density was betweenâ…¡andâ…¢,Cd could be the important element to affect bacteria community structure.Different microorganisms have an obviously different response to Cd pollution in soil. In purple soil,fungus had a negative relationship with Cd content,which can reflect Cd pollution level sensitively.In alluvium,a significant positive association was found between Cmic/Corg and Cd content under densityâ… level;while under densityâ…¢level, there was significant negative correlation between Saccharase activity and Cd content,but significant positive relationship was found between Cmic/Corg and Cd.In this system also found that dehydrogenase/Corg was also positively correlated with logarithm of Cd content.