pH和有机质对三种不同土壤镁吸附特性的影响

Effects of pH and Organic Matter on Adsorption of Magnesium in Soil

选取黄壤、紫色土和石灰性土3种土壤为研究对象,采用一次平衡吸附法,研究了pH、有机质对镁吸附的影响.结果表明,不同pH和有机质条件下,土壤对镁的最大吸附量有较大差异,黄壤和紫色土受pH影响较明显,在pH3.5~7.5这个范围,黄壤对镁的最大吸附量变化在1 336.25g^2 054.77 mg/kg,紫色土在1 417.04~2 025.38 mg/kg,石灰性土变化不大.去有机质后,黄壤、紫色土和石灰性土对镁的吸附能力下降,最大吸附量分别减少363.31,148.72,120.00 mg/kg.Langmuir方程能很好的拟合土壤对镁的吸附过程.

The effects of pH and organic matter on adsorption of magnesium in yellow soil, purple soil and calcareous soil were studied in a batch adsorption experiment. Considerable differences were observed among the three soils in their maximum Mg adsorption under different pH and organic matter conditions. The adsorption of magnesium was mainly related to the changes in pH in yellow soil and purple soil. In the pH range of 3.5-7.5, the maximum magnesium adsorption varied from 1 336.25 to 2 054.77 mgkg^-1 in the yellow soil and from 1 417.04 to 2 025.38 mg .kg^-1 in the purple soil, while little change was detected in the calcareous soil. The ability of Mg adsorption decreased after the removal of organic matter in the above three soils and the maximum Mg adsorption decreased by 363.31 mg.kg^-1, 148.72 mg .kg^- 1 and 120.00 mg .kg^-1 , respectively. Magnesium adsorption in soils was well fitted with the Langmuir equa- tion.