Effects of different management of double-decked awning on growth and development in tobacco seedling with float system

The effects of different management of double-decked awning on the growth and development in tobacco seedling with float system were researched. The results showed that double-decked awning with covered membrane inhibited the development of stem and the accumulation of phosphorus in the leaves, raised surface temperature of the tray to the best level, and reduced the light intensity on surface of the tray; double-decked awning with uncovered membrane improved the quality of seedling more significantly and reduced temperature at daytime to keep the change of environmental temperature smoothly, it was the suggested management in application.