Interaction between Nitrogen Application Rate and Planting Density on Agronomic and Economic Characters of Flue-cured Tobacco

A field experiment was conducted to determine the optimum nitrogen (N) application rate and planting density for better growth, higher yield and economic benefit of flue-cured tobacco and to provide scientific basis for production with high yield and quality using Qinyan 96 cultivar in this study. The split-plot experiment design with three regimes of planting density (A) and N rate (B) was applied to study the interaction between nitrogen and density on agronomic characters at round top stage, yield and economic characters of flue-cured tobacco. The results showed that optimal N rate and planting density could improve growth and development, enhance yield and economic benefit of flue-cured tobacco. Regardless of planting density, the best responses recorded under the high and medium N rate. Under the low/high N rate, the best responses recorded under the medium and high planting density while medium N rate under low and medium planting densities. The interaction between N rate and planting density was significant and the responses from the former were greater than those from the latter. System cluster analysis indicated that nine treatments combinations were classified into five ranks, of which best treatment combinations were A2B2 and A2B3, followed by A1B2 and A3B2. On the consideration of comprehensive analysis, the appropriate planting density and nitrogen rate of Qinyan 96 are 16 698 plant/hm² and N 180 kg/hm² respectively. Conclusively, to modify N rate and planting density could increase the use efficiency of fertilizer and enhance the yield and quality of flue-cured tobacco based on the interaction between them.