Effects of Rational Application of Magnesium Fertilizers on Growth, Yield and Quality of Flue-cured Tobacco

A field experiment was conducted to investigate the effects of magnesia, limestone and calcium-magnesium-phosphate combination fertilizers on tobacco growth, yield and quality on soils with poor magnesium content in Nanping area so that magnesium fertilizer could be rationally applied. The results showed that magnesia had the best effect in increasing magnesium contents of tobacco leaves, and was superior to limestone and calcium-magnesium-phosphate combination fertilizer. Application of magnesium fertilizers could increase leaf magnesium content remarkably, improve appearance quality, especially to maturity of upper leaves. In chemical composition of the tobacco leaves, magnesium was very significantly and negatively correlated with nicotine content, and very significantly and positively correlated with ratios of reducing sugar to nicotine. In smoking quality, magnesium in tobacco leaves was a beneficial factor, and significantly and positively correlated with combustibility and ash color. In conclusion, magnesia is a required fertilizer for soils with magnesium deficiency in Nanping.