This paper is the result of environmental geological survey engineering.

Objective Lianjiang Dam is located in Huishui County of Guizhou Province. To find out the Se distribution features of soil in Lianjiang Dam, 337 surface soil samples, 4 soil mother rock samples and 16 soil profile samples were collected, and the contents of Se, nutrient elements and heavy metal elements such as As、Cd、Cr、Cu、Hg、Ni、Pb、Zn were analyzed and determined.

Methods The contents of Se, nutrient elements and heavy metal elements in the samples from surface soil, soil mother rock and soil profile were compared and the Se distributions features of soil were evaluated based on correlative analysis method.

Results It showed that the soil in this area were acidic with the contents of Se in the soil from 0.19 to 3.65 mg/kg. The contents of nutrient elements such as P, B and SOM in the soil were high. The average Se values of surface soil of different mother rocks in this area appeared the transformation law: Upper Carboniferous limestone > Middle Permian Maokou Formation limestone > Middle Permian Qixia Formation limestone > Upper Cretaceous Maotai Formation sandstone > Middle Triassic Luolou Formation limestone > Middle Triassic Bianyang Formation clastic rocks. The Se contents of soil profile in this area decreased with the depth deepening.

Conclusion The Selenium−rich soil is abundant in this area, mainly of medium and high. The area of selenium−rich soil is about 42.94 km². There is a significant positive correlation between Se and SOM, while a significant negative correlation between Se and K₂O, and pH in soil.