| The flue-cured tobacco plays an important role in economy of China. Tobacco production is frequently limited by regional and seasonal drought stress in Guizhou province. In order to avoiding the effects of drought stress in tobacco production, field experiment with mulched drip irrigation and its demonstration were carried out between2010and2011in Guizhou province. Therefore, soil water movement and tobacco yield&quality with drip irrigation under plastic film were analyzed in this experiment. Main results are as follows:(1) Continuous observation on dynamical migration of soil wetting front and soil water distribution was conducted with TDR measurement techniques after Oh and24h with drip irrigation under plastic film, respectively. The results showed that movement speed of soil wetting front had a gradual reduction as irrigation time was extended. The overall distribution of soil-water contour was approximately oval, and coincided with the general characteristics of soil water distribution. Due to evaporation, in soil sub-surface soil water content was9.2percent lower than the initial moisture content after24h when irrigating; in addition to the re-distribution of soil water content, shape and extent of the soil moist had also been larger change; irrigation water reached70cm at sub-surface, however, wet soil body in the horizontal direction of migration was not obvious.(2) With random block design, convention production without drip irrigation which nitrogen rate was75kg/hm2as the control, and nitrogen rate45,60and75kg/hm2and drip1,2and3hours as the treatments were used in field experiment of flue-cured tobacco, respectively. The results indicated that effects of nitrogen application levels and irrigation frequency on flue-cured tobacco were significant differences. In the case of the same nitrogen rate, drip irrigation with3h had better overall performance, especially to agronomic characters, tobacco yield and production value; with the same irrigation time, agronomic characters, tobacco yield and production value were significantly enhanced with nitrogen application levels between60kg/hm2and75kg/hm2.When drip irrigation time3h, yield, production value and average price of flue-cured tobacco were15375kg/hm2and1584kg/hm2.22662.75yuan/hm2(RMB) and23205.60yuan/hm2and14.74yuan/kg and14.65yuan/667m2, respectively.(3) Drip irrigation and conventional watering increased biomass of flue-cured tobacco, plant height and stem girth were better than convention production in flue-cured tobacco. Dry matter accumulation were224.2g and165.8g per plant with drip irrigation and conventional watering, which were increased more109.2%and55.8%compared with the control, respectively; production quality was also superior to the control. Compared with the control, yield and quality of flue-cured tobacco were better with drip irrigation and conventional irrigation.(4) The results showed that compared with conventional control, growth, maximum leaf length, maximum leaf width and stem girth of tobacco plant were improved with drip irrigation under plastic film. Tobacco production and value with drip irrigation were2128.5kg/hm2and30,939.6yuan/hm2, and enhanced by93kg/hm2and4819.2yuan/hm2compared with the control, respectively; average price of tobacco in drip irrigation increased by1.6yuan/kg compared with the control. Harmonious equipotentiality of chemical composition and smoking feeling were improved, and proportion of superior tobacco and upper-middle-tobacco ratio slightly increased. Therefore, income of farmers was increased more than20percent. However, the high cost of initial investment and operation and management for drip irrigation under plastic film was not conducive to the autonomous use of the tobacco growers. |
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