Effects of Application Rate of Nitrogen, Phosphorus and Potassium in Loess Soil on Yield and Quality of Yunyan 87 and Its Recommended Formula

By studying the fertilizer effects of different nitrogen, phosphorus and potassium fertilizer application rates on flue-cured tobacco under the condition of medium-fertility loess soil, to provide scientific basis for rational fertilization in this soil type tobacco area. Using Yunyan 87 as the test material, the “3414” field experiment design was used to analyze the agronomic characters, chemical components and economic indicators of flue-cured tobacco, and the NPK fertilizer rate was fitted by the fertilizer effect function equation. The agronomic characters and chemical components of different treatments are quite different. Comprehensively analyzing the growth and development of flue-cured tobacco and the performance at maturity, as well as the analysis of improving the yield and economic benefits of flue-cured tobacco in the later period, the effect of treatment T5 is the best. The established equation model can predict that the maximum fertilizer rates of N, P and K are 12.83 kg/666.67m 2 , 35 kg/666.67m 2 and 34.04 kg/666.67m 2 , respectively. From the perspective of comprehensively improving the economic benefits of flue-cured tobacco, the optimal fertilization rate is 12.5 kg/666.67m 2 of urea, 18 kg/666.67m 2 of superphosphate, and 33.2 kg/666.67m 2 of potassium sulfate.