Effects Of Water And Nitrogen Coupling In Micro-jet Conditions On The Output Value, Qualit And Nitrogen Use Efficiency Of Flue-cured Tobacco

Abstract：A field experiment with the means of the two factors and five levelsquadratic orthogonal rotation combination design was performed to study effects ofwater and nitrogen coupling in micro-jet conditions on the output value, accumulationamount of dry matter, nitrogen utilization efficiency, physical properties, neutralaroma components and inherent quality of flue-cured tobacco. The results of thisstudy showed that:1Effects of water and nitrogen coupling in micro-jet conditions on the outputvalue of flue-cured tobaccoThe single factor analysis showed that: the output value increased first and thendecreased with the increased of nitrogen and irrigation application. Theinteraction-effect analysis showed that: the synergistic role was produced betweenwater and nitrogen on the output value of flue-cured tobacco under the conditions ofthe less than+1level of nitrogen amount and the less than0level of irrigation amount;while the antagonism was produced between water and nitrogen on the output valueof flue-cured tobacco under the conditions of the more than+1level of nitrogenamount and the more than0level of irrigation amount; comprehensively consideredthe coefficients of one degree term, quadratic term and interaction item based on theregression equation, effects of nitrogen, water and interaction of water and nitrogenwere different on the output value of flue-cured tobacco, in the order of nitrogenfertilizer> irrigation> interaction of water and nitrogen fertilizer. The extreme valueof regression equation was40233.97yuan·hm^-2under the conditions of132.57kg·hm^-2purity nitrogen and262.26m³·hm^-2irrigation.2Effects of water and nitrogen coupling in micro-jet conditions on accumulationamount of dry matter and nitrogen utilization efficiency of flue-cured tobaccoThe accumulation amount of dry matter increased with the increased of nitrogenapplication, while did not change significantly with the increased of irrigation. Thenitrogen utilization efficiency increased first and then decreased with the increased of nitrogen application, while increased totally with the increased of irrigation; themaximum value of nitrogen utilization efficiency was63.63%under the treatmentcombination conditions of^-1 level of nitrogen application and+1level of irrigation;the minimum value of nitrogen utilization efficiency was49.24%under the treatmentcombination conditions of+1.414level of nitrogen application and0level ofirrigation.3Effects of water and nitrogen coupling in micro-jet conditions on chemicalquality of flue-cured tobaccoWith the increased of nitrogen application, total nitrogen, nicotine, pigments andpetroleum ether extract increased; total sugar, reducing sugar, total sugar/totalnitrogen, total nitrogen/nicotine reduced, these indexes were different significantly.The indexes of nicotine, Cl, carotenoid of middle leaves, total sugar, reducing sugar ofupper leaves and total nitrogen, K, chlorophyll a, and total sugar/total nitrogen weredifferent significantly for irrigation, while the remaining indexes were not differentsignificantly.A regression equation of water and nitrogen on fuzzy comprehensive evaluationscore was established, the results showed that: the regression equation was an openingdown parabola, indicated that the total score of the comprehensive evaluationdecreased under the conditions of too much or too little nitrogen and irrigationapplication. comprehensively considered the coefficients of one degree term andquadratic term based on the regression equation, effects of nitrogen and water weredifferent on the total scores of fuzzy comprehensive evaluation, in the order ofnitrogen fertilizer> irrigation. The extreme value of regression equation was7.3543under the conditions of78.69kg·hm^-2purity nitrogen and383.07m³·hm^-2irrigation.4Effects of water and nitrogen coupling in micro-jet conditions on neutralaroma components of flue-cured tobaccoComprehensively considered the coefficients of one degree term and quadraticterm based on the regression equation of neutral aroma components, effects ofnitrogen and water were different on neutral aroma components, in the order ofnitrogen fertilizer> irrigation. In addition to decreased the part of neutral aromacomponents content which classified to cembranoid with increased of nitrogenapplication, while other neutral aroma components contents significantly increasedwith the increased nitrogen and irrigation application by the coefficients of one degreeterm of the regression equation. the part of neutral aroma components content which was classified to phenylalanine of middle leaves and the part of neutral aromacomponents content which classified to membranous of upper leaves increased withthe increased of nitrogen application. the part of neutral aroma components contentwhich classified to membranous of middle leaves increased with the increased ofirrigation application, while the other neutral aroma components of tobacco leavesreduced under the conditions of more or less nitrogen and irrigation application.