Abstract: The soil fertility characteristics of different preceding crops in the Cangling base of Youyang county were studied. The results showed that①Tobacco soil with corn as the previous crop88.24% of the soil pH were suitable for the growth of tobacco plants, 11.76% of the soil samples were located in the suitable range about soil alkali hydrolyzable nitrogen, 29.41% of the soil available phosphorus was located in the suitable range of tobacco growth, and 58.82% of the soil sample available potassium content was lower than 150 mg/kg, and the average content of organic matter was on average of 14.97 g/kg, and the soil samples with chloride content ranging from 10 to 30 mg/kg account for 58.82% of the total. ②Tobacco soil with vegetables as the previous cropThe soil pH was suitable for the growth of tobacco plants. The content of alkali hydrolysable nitrogen was not suitable for the growth of tobacco plants. The content of available phosphorus in 33.33% soils was located in the suitable range. The content of available potassium in soil less than 150 mg/kg accounted for 50%, the average value of soil organic matter content is 16.91 g/kg, and the content of chlorine ion of 66.67% soil samples located in the soil was in the suitable range of the growth of the tobacco plant. ③The soil with tobacco as the previous crop20.78% soil pH was not suitable for the growth of tobacco plants, only 5.2% soil alkali hydrolyzable nitrogen was within the suitable range, 62.34% of the soil available phosphorus content was not suitable for the growth of tobacco plants. 53.25% of the soil available potassium content was suitable for the growth range of tobacco plants, the average organic matter average is 15.53 g/kg, soil samples with chloride ion content of 10~30 mg/kg accounted for 68.83%. ④Some corresponding countermeasures were put forward according to the soil nutrient content.

Key words: flue-cured tobacco, soil, fertility characteristics, previous crop