中文摘要：

pH和三种竞争性阴离子对紫色土亚硒酸盐吸附一解吸的影响的研究结果表明，随着pH的增大，紫色土对亚硒酸盐的吸附量减少，酸性条件下紫色土对亚硒酸盐吸附量最大。平衡液中加入磷酸氢二钠显著降低了土壤对亚硒酸盐的吸附，硫酸盐对紫色土吸附亚硒酸盐的影响很小，低浓度碳酸氢根离子对紫色土吸附亚硒酸盐具有促进作用，但高浓度的碳酸氢根离子则降低了紫色土吸附亚硒酸盐。磷酸氢根离子和硫酸根离子对亚硒酸盐吸附的影响符合Langmuir和Freundlich拟合方程式，决定系数R^2值均在0．90以上。三种阴离子对亚硒酸盐的解吸影响不同，当有磷酸氢根离子和碳酸氢根离子存在时，亚硒酸盐的解吸率增大，而硫酸根离子的存在却对紫色土亚硒酸盐的解吸影响不大。在紫色土地区农业生产中采用含磷酸盐肥料和碱性碳酸氢铵肥料，这些措施可能增加土壤硒的有效性，进而增加植物硒吸收和积累。认识紫色土固液界面硒的吸附一解吸规律，可为提高紫色土地区硒生物有效性，从而进一步提高农产品中硒含量提供科学依据。

英文摘要：

In agriculture production, the application of compound fertilizers and phosphate fertilizers bring into the soil large volumes of anions, dominated with phosphate, sulfate and carbonate, which in turn affect selenium availability in the soil to crops. The studies in the past on selenium adsorption-desorption used to focus on fitting of selenium adsorption with the isotheral equation fitting and effects of single factors on selenium adsorption, and little has been reported on selenium sorption in purple soil and effects of anions on the sorption. Purple soil is the main type of soil in the Sichuan Basin, where neutral purple soil is the highest in area. The study on effects of soil pH and three competitive anions on absorption and desorption of selenium in the purple soil reveals that with increasing soil solution pH, the soil declined in Se adsorption. Selenite adsorption in purple soils varied in the range between 26% to 82% in neutral purple soils, peaked up to 130.1 tool kg^-1, when soil pH was 3, and bottomed to 26% only when soil pH was 9. This shows that soil pH may directly affect the concentration of selenite in soil solution, and hence plant uptake of selenium. With rising soil pH, purple soils reduced their adsorption of selenite, and maximized the adsorption when they were acidic. Effect of HPO4^2- on selenite adsorption in purple soils was reflected in the finding that selenium adsorption in the soil decreased significantly or by 39.62% when 0.2 mmol L^-1 of HPO4^2- was amended. However, the effect became less significant as more HPO4^2- was added. Addition of HPO4^2- into the equilibrium solution significantly reduced soil absorption of selenium, while addition of SO4^2- did not have much impact on purple soil adsorption of selenium. When 0.3 mmol L^-1 of HCO3^- was amended, soil adsorption of selenite was significantly increased or by 20.37%, but the effect got to be less significant when more HCO3^- was added. When 6.5 mmol L^-1 of HCO3^- was added, the anion displayed slight competition with sel