In order to investigate the coupling effects of nitrogen fertilizer rate and planting density on economic traits and chemical quality of flue -cured tobacco in Liuyang tobacco area,a field experiment with 3 nitrogen application rates,150 kg/hm2 (A1),180 kg/hm2 (A2)and 210 kg/hm2 (A3),and 3 planting densities,15 000 plant/hm2 (B1),16 500 plant/hm2 (B1)and 18 000 plant/hm2 (B1),were carried out.The results showed that (1)the yield and output value showed the increase -decrease trend with the increment of nitrogen application rate and planting density in this study,and the cou-pling effect of A2B...