Effects of Soil Chemical Properties and Altitude on K Content in Flue-cured Tobacco Leaves in Qujing Area

The relationship between potassium content in middle leaves of flue-cured tobacco and soil nutrients with attitude was investigated to identify the relationship of chemical properties between tobacco planting soils and flue-cured tobacco leaves in Qujing, Yunnan Province. The results showed that the mean content of potassium in tobacco leaves in Qujing was 1.51%, ranging from 0.29% to 3.01%. Tobacco potassium content in Qujing was mainly affected by soil available potassium, and increased with the increment of soil available potassium. Furthermore, when the soil available potassium was less than 175.22 mg/kg, tobacco potassium content was greatly affected by soil available magnesium. When ranging from 175.220 to 276.010 mg/kg, water soluble chlorine in soil was the main factor affecting tobacco potassium content. When exceeding 276.010 mg/kg, tobacco potassium content was mainly affected by soil available magnesium. Otherwise, soil organic matter and sampling site altitude also had certain effect, where the altitude cut-points were 1700, 1822 and 2023 m, respectively. Tobacco potassium content decreased with altitude increasing.