Effects and mechanism of different ridge heights and cover practices on yield and quality of burley tobacco and effects of several integrative cultivation practices on soil nitrification and denitrification and on root development,nicotine concentration,and tobacco yield were studied.Results showed that 10cm ridge and film-covering can enhance intensity of nitrification during rosette stage,while reduce intensity of denitrification before rosette stage and after fast growing period,which were useful for promoting nitrogen supply during early stage and reducing denitrificational loss of soil nitrogen.Film-covering was more beneficial for root development compared with non-film-covering.Among the four treatments of ridge height,10cm ridge was more propitious to the generation of adventitious roots and ramification of superior roots,which formed more harmonious distribution of root in soil.Nicotine concentration in leaf increased with increased ridge height,and film-covering.Compared with non-film-covering,film-covering resulted in higher leaf yield,production value,leaf price,and the percent of good quality leaf.Among the four ridge heights under film-covering,10cm ridge resulted the best leaf yield and production value.As far as nicotine concentration and leaf yield are concerned,10cm ridge and film-covering is the optimum integrated cultivation model for higher leaf yield and quality.

[Objective] The aim was to perfect the breeding technique of tobacco and improve the seedling quality.[Method] With the seedlings of E'yan No.1 as the materials,different artificial light were taken for supplemental lighting treatment,and the effects of supplemental lighting on growth of tobacco seedlings were studied.[Result] The spectral range that tobacco leaf absorbed and used on visible light was wide.The absorption intensity of tobacco leaf on different wave band light in order was blue lightgreen light red light purple light.At 14 d of supplemental lighting,the common fluorescent lamp treatment could significantly increased the chlorophyll a content of tobacco seedling and common fluorescent lamp,bio-effect lamp and green fluorescent lamp treatments could significantly increased chlorophyll b content of tobacco seedling.At 21 d of supplemental lighting,blue fluorescent lamp and red fluorescent lamp treatments could significantly increased chlorophyll a content of tobacco seedling and incandescent lamp,energy saving lamp treatments could significantly increased chlorophyll b and chlorophyll a+b contents of tobacco seedling.All lamps all could promote dry matter accumulation of tobacco stem and the treatment effects of incandescent lamp,energy saving lamp and bio-effect lamp were the best.[Conclusion] Incandescent lamp was the first choice in technology of supplemental lighting breeding of tobacco.