Impact of Imidacloprid Seed Dressing Treatment on Soil Microorganisms and Enzyme Activities in the Maize Rhizosphere

Under the field conditions, effects of imidacloprid seed dressing treatment on soil culturable microorganisms and enzyme activities in maize rhizosphere were studied. The results showed that the microbial populations for bacteria, actinomycetes and fungi in maize rhizosphere after imidacloprid treatments were lower than control. The bacteria and actinomycetes populations showed a trend of decreasing after increasing with the maize growth from the seedling stage to the maturity stage, and the fungi populations decreased with the maize growth. The urease activities of maize rhizosphere soil from different treatments showed a trend of initially increasing after decreasing, then decreasing. The invertase activities of maize rhizosphere soil from different treatments showed a trend of decreasing after increasing, and the peak value occurred at flowering stage. With the imidacloprid application, the invertase activities had been stimulated. The results may provide theoretical basis for rational seed dressing treatment.