Study on reducing proportion of potassium nitrate in top-dressing on flue-cured tobacco

In this paper, flue-cured tobacco cultivar (Nicotiana tabacum Yun 87) was selected to explore whether ammonium phosphor nitrate (APN) alone or associated with potassium sulfate(K2SO4) could help reduce the proportion of potassium nitrate(KNO3) in top-dressing on flue-cured tobacco (FCT). A field experiment was conducted in randomized block design containing three replicates in seven treatments. Results showed, it was the most optimum treatment for improving the economical properties of FCT to apply 148.5kg/ha KNO3 together with 19.5kg/ha APK at traditional top-dressing time and following 75kg/ha K2SO4 after lower leaves harvest. In the meantime, this treatment was also the most optimum way to improve the chemical properties of FCT. Moreover, it enhanced 6.8% of plant height value of FCT over control group and its plant height was higher than that of other treatments. In a word, decreasing the amount of KNO3 and adding APN plus K2SO4 into top-dressing can be more favorable for the physical growth, quality and yield index of FCT than only KNO3 on FCT and this new fertilizing scheme could both increase income and decrease investment of FCT-growers.