Soil Available Silicon Content in Flue-cured Tobacco in Zhunyi

In order to identify the distribution of soil available silicon in Zhunyi tobacco area, 87 soil samples of plow layers from Zhunyi county and Renhui county were analyzed. The results indicated that soil available silicon content ranged from 30.24 to 444.89 mg/kg, with an average of 169.75 mg/kg, and the variation coefficients was 73.27%. If using 100 mg/kg as the deficient critical point of soil silicon, 20.69% of the soils were silicon deficient. Soil available silicon content was found that yellow soil > calcareous soil > rice soil, and in term of soil parent material, shale > limestone > dolomite > marl > dolomite limestone >Quaternary clay > yellow sandstone. There was no significant relationship between the soil available silicon content and the organic content or the altitude of sampling points, but there were significantly positive correlations between the soil available silicon content and the soil pH.