土壤粒级和酸度对硒吸附固定的影响

用砖红壤样品和亚硒酸钠进行实验，结果表明，土壤粒级和酸度对硒的吸附固定有明显影响，土样粒径越小和酸度增加，对硒的固定作用加强。〉１ｍｍ粒级对硒几乎没有固定能力，〈１．０ｍｍ粒级固定作用显著增大。当ｐＨ２￣３时，粘土矿物（经电镜和Ｘ射线监定绝大多数为高岭石）固定硒的量最大，当ｐＨ〉３时，固定硒的量随ＰＨ值的增加而逐步降低，至ｐＨ６￣８时，固定能力变化不明显。

Effects of Soil Separate and Soil Acidity on Selenium Absorption and Fixation

The effects of soil separate and soil acidity on Se absorption and fixation were studied. The results show that the smaller the soil particle and the higher the acidity is, the stronger ability the Se absorption and fixation has. When the pH value ranges from 2 to 3, the amount fixed Se of clay mineralreachesthe highest; when the pH value ranges from 3 to 8, the amount decrease gradually.