Effects of Nitrogen and Phosphorus Fertilizers on Physical and Chemical Characteristics and Enzyme Activity of Soil and Tobacco Growth under Film Mulch

The synergic effect of nitrogen and phosphorus fertilizers on physical and chemical characteristics of tobacco planting soil, enzyme activity and tobacco growth under film mulch were studied with field experiments.The results showed that by film mulching, soil temperature, neutral phosphatase activity and the amount of nitrogen and phosphorus absorbed by tobacco plant were increased, the shoot growth and development of tobacco were promoted significantly.However, the ratio of root and shoot and the Eh and pH of soil were decreased, weak soil nitration might be resulted and the absorbing rate of tobacco plant to NO₃^--N was decreased.The urease activity in the soil was declined with the increase of urea and phosphorus fertilizer and by film mulching as well.