Effect of combined application of N, P and K fertilizers on chemical composition of flue-cured tobacco in south Shaanxi Province

【Objective】The study was to evaluate the chemical composition of flue-cured tobacco comprehensively,and to get the best N,P and K fertilization program.【Method】The field N,P and K fertilization experiment was designed with the method of three-factor five-level two orthogonal revolving combination.The 16 different fertilizations on chemical composition of flue-cured tobacco in south Shaanxi tobacco growing area were analyzed by factor analysis.Four principal components with accumulative contribution were obtained.And also the score equation of different fertilizations on chemical composition of flue-cured tobacco was obtained.Chemical composition of flue-cured tobacco score was used as a new indicator to conduct hierarchical cluster analysis.【Result】The 13 terms of chemical composition of flue-cured tobacco all give good explanation in the evaluation of different fertilizations.The chemical composition of flue-cured comprehensive tobacco scores equation was obtained by the factor analysis.And using the comprehensive scores as the new index,the hierarchical cluster analysis was carried out.The 16 different fertilizations were divided into 6 ranks,of which best fertilization was the No.8.【Conclusion】When the fertilizer rates were N at 107.84 kg/hm2,P at 146.75 kg/hm2,K at 212.63 kg/hm2,the chemical composition of flue-cured tobacco was the best in this experiment.