Urea is the most popular N fertilizer used in China.Field experiments were conducted to investigate the effects of nitrogen application on the quantity of microorganisms,activity of enzymes and yield of Chuzhou Chrysanthemum morifolium Ramat.Results showed that urea application had significant effects on the quantity of microorganisms and activity of enzymes.Change of soil bacterium,fungus,actinomycete and soil enzyme activity of protease,catalase,urease showed a single-peaked curve,respectively with the in...