Effects of coated controlled-release fertilizers on potassium content in tobacco leaves

Nutrient release experiments of controlled-release fertilizers(CRFs)and field experiments of tobacco were conduct- ed to study nutrient release features of CRFs and effects on potassium content in tobacco leaves.Results showed that nutrient release of CRFs could meet the nutrient requirements of flue-cured tobacco and markedly increase soil available potassium and potassium content in leaves.Compared to that with general treatment,potassium content in tobacco leaves with CRFs treatment under three fertilization levels increased by 1.88 %,1.62%,and 1.68% respectively at maturing stage.The highest growth of potassium content in upper leaves were 1.01%,1.07%,and 1.15%,and in middle leaves were 0.8%,0.85%,and 1.02%,respectively.Application of CRFs not only increased potassium content in leaves but also saved 1/3 to 2/3 of all the fertilizers.