Study On Water Consumption Characters And Water-saving Irrigation Of Flue-cured Tobacco

At Hubei tobacco academic agricultural institute and Yunnan tobacco academic agricultural institute from 2004 to 2005, the artificial water controlling experiments were conducted to study the changes of physiological characteristics and water consumption characters in flue-cured tobacco under water-saving irrigation and the technologies of regulation deficit irrigation and root-divided alternative irrigation in flue-cured tobacco by K326. The main results were as follows:1 Effects of drought stress on seeding growth and resistance physiology of early-maturing flue-crued tobacco. The results showed that the photosynthesis and growth were obviously reduced by drought stress. Compared to contrast treatment, chlorophyll a content of drought treatment decreased in the periods of drought treatment, chlorophyll b and total chlorophyll contents increased at the beginning of drought treatment, then decreased with decreased with increasing drought stress, but the ratio of chlorophyll a/b is the opposite trend. With the time of drought prolonged, leaf water relative content descended rapidly, its leaf water retention capability descended slowly, the contents of soluble sugar and soluble protein increased obviously.2 The plant height and leaf area were increased obviously with the increasing of soil relative water content at various growing stages. The dry matter content and distribution were complicatedly affected by soil water, which had a little effect on the number of leaves. The NR activity was decreased with the decreasing of soil relative water content. The root activities of different treatments manifested W2 (55 % -65 %) >W1 (45%-55%) >W3 (65%-75%) at root spreading stage, W2 (75%-85%) >W3 (85%-95%) >W1 (65%-75%) at vigorous growing stage , W2 (75%-85 %) >W1 (65%-75%) >W3 (85%-95%) at maturing stage. Suitable soil moisture indexs for tobacco have been advanced, which were 58.8% at root spreading stage, 80.1% at vigorous growing stage, 78.3% at maturing stage based on relationship between leaves chlorophyll content and soil water.3 In the whole growing period of tobacco plant, the change of evapotranspiration had a single-peak curve. With the adding of soil water content, the evapotranspiration...