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Water is one of the two ecological factors in the growth of tobacco and tobacco yield and quality formation , is also the primary means of effective regulation of tobacco production and quality . Tobacco has a strong drought resistance , water deficit exceeds a certain limit , the reactions are very sensitive to drought . Soil moisture stress , the physiological characteristics of the tobacco changes in stomatal conductance smaller stomata partially Close , thereby affecting the water vapor and CO 2 exchange , photosynthetic rate and transpiration rate decreased . To weaken due to transpiration , canopy temperature , making the the tobacco water stress index CWSI increased concentration of the cell sap . The the Lysimeter pot experiment results show that in the flue-cured tobacco at different growth stages can be appropriately regulated deficit irrigation , and not be a huge impact on the yield and quality of flue-cured tobacco . Tobacco root spreading , vigorous maturity of the lower limit of the optimum moisture control 60-80-70 ( percent) for the field capacity . Root spreading period is a critical period of the Tobacco Root Growth , moderately regulated deficit irrigation can promote tobacco rooted depth ; prosperous long-term tobacco yield formation period , moderately regulated deficit irrigation can control, so as to avoid tobacco growing \Therefore, regardless of the formation of the yield and quality of tobacco , or from the point of view of saving water , should the tobacco appropriately regulated deficit irrigation .
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