Abstract: In order to find out the effects of soil fluorine on ecological environment and crop safety in the sorghum cultivation base of Renhuai City, Guizhou Province, the content and the occurrence form of soil fluorine and its influencing factors of Maoba Town were investigated and studied. The results showed that the total fluorine content in sorghum base soil ranged from 668.60 to 2 596.80 mg/kg, with an average of 1 483.25 mg/kg, which was 3.10 times and 1.85 times of the national soil background value and the average value of the soil in endemic areas. The spatial distribution of fluorine in the soil of the study area was uneven, and the fluorine content was in the order of Anliang Village> Yangliu Village> Houba Village> Xiongfeng Village. The soil fluorine contents of various forms varied greatly, and the distribution law was as follows： residual state> water soluble state > organic bound state > exchangeable state > Fe-Mn oxidation state. The residual fluorine content was the highest, accounting for more than 99% of total fluorine content, while the sum of the other four forms was less than 1%, with their respective proportions ranging from 0.10% to 0.30%. The content and proportion of available fluorine in water soluble and exchangeable states were relatively low, which had limited influence on the surrounding water environment and crop safety. The physicochemical properties of soil, such as pH, organic matter, cation exchange capacity and clay particles had a certain influence on the occurrence form of soil fluorine, thus changing the availability and migration of soil fluorine, which might endanger the ecological environment safety, food safety and human health.

Key words: sorghum base, soil, fluorine, occurrence form, distribution characteristics, Renhuai City