Effects of interaction of potassium, calcium and magnesium on flue-cured tobacco growth and nutrient absorption

Trial results showed that application of potassium, calcium and magnesium remarkably increased the content and total uptake of potassium, calcium and magnesium in flue-cured tobacco. The interaction existed in potassium, calcium and magnesium, which was not simply antagonistic. Potassium antagonized calcium and magnesium absorption. Calcium antagonized the absorption of magnesium but promoted the absorption of potassium. The research indicated that yield and the ratio of high quality tobacco were increased remarkably on the condition that the ratio of potassium, calcium and magnesium in plant was 1:0. 54:0. 07, which were 2 958 kg·hm~(-2) and 57.97%. It was suggested that optimum application ratio for K~(+), Ca~(2+) and Mg~(2+) was 1.0:1.0-2.0:0.1 -0.15, which was advised as reference index for the balance of potassium, calcium and magnesium in fluecured tobacco.