The Research Of Water And Nitrogen Coupling Effect On The Flue-cured Tobacco

This paper focuses on the following research by means of pot experiments and field tests: the law of water demand in the tobacco growing period; the changing situations of the utilization of nitrogen under the condition of the water and nitrogen coupling effects; the distribution of soil moisture under the water and nitrogen coupling effects, and the influence of the water and nitrogen coupling effects on the yield and quality of the flue-cured tobacco. The purposes of this study are to find a suitable form of the water and nitrogen coupling in the drought breathing zone. So as to provide bases for the fertilizer application in water availability fertilizer, manure water, a scientific and rational way during the process of production, and to insure the yield and quality of the flue-cured tobacco under the suitable moisture.1. The research on the suitable moisture conditions in the different periods a quality flue-cured tobacco productionThe results show that: the suitable soil moisture is 55%～65% in the extended period; 75%～85% in the blooming period; 65%～75% in the optimum maturity.2.The impact which is exerted by the water and nitrogen coupling effects on the distribution, the utilization of water and the water output.the soil moisture storage capacity decreases with the increase of the nitrogen amount the soil moisture storage capacity with the nitrogen application amount of 90kg/hm~2, reaches the maximum of 225mm in the condition of paying water.The water utilization with the fertilizing amount of 90kg/hm~2is the highest on the conditions of paying water ,and reaches 4.26kg/(mm·hm~2), the production rate of water with the fertilizing amount of 90kg/hm~2, reaches the maximum of 28.12 Yuan/( mm·hm~2) in the condition of paying water.3. The impact is exerted by the water and nitrogen coupling effects on the nitrogen utilization After water couples with nitrogen , both the nitrogen utilization and the increase output of nitrogen reach the highest are separately 43.39% and 31.27%.The nitrogen application amount of the flue-cured tobacco reaches 90kg/hm , with the increase of the nitrogen application amount, the increase quantity of the dry flue-cured tobacco appears the declining tendency. In the conditions of paying water absorption amount of nitrogen takes 120kg/hm~2 treatment as the maximum, and reaches 86.4kg/hm~2 , in the conditions of paying water. there is not obvious differed in the total absorption amount of nitrogen between 90kg/hm~2 treatment and 120kg/hm~2, only 2.6kg/hm~2 .on the conditions of 90kg/hm~2 nitrogen utilization the nitrogen utilization and the nitrogen increase output of the flue-cured tobacco without paying water are separately 34.48% and 26.34%, which with paying water separately reaches 43.3%and 31.27%,paying water increases 8.91% and 4.93% than no paying water.4. The choose of the best form of water and nitrogen coupling for the quality flue-cured tobacco production in Guizhou provinceFrom the point of view of agronomic traits the 90kg/hm~2 treatment is the best on the conditions of paying water.The proportion of superior tobacco and the proportion of upper-middle tobacco through the 90kg/hm~2 treatment are much better than ones through other treatments and separately reaches 1648.8yuan/hm~2 and 10.82yuan/kg, 24.6% and 69.2% . the suitable soil moisture can significantly reduce the nicotine content of its upper part and make its quality better, through the 90kg/hm treatment.The RWC of soil in the blooming period is 75-85%, the nitrogen application amount of 90kg/hm~2 is the best form of water and nitrogen coupling for the quality flue-cured tobacco production.