Adsorption of atrazine and phosphate as affected by soil depth in allophanic and non-allophanic soils

作者：Magesan GN^*; Bolan NS; Lee R

来源：New Zealand Journal of Agricultural Research, 2003, 46(2): 155-163.

• adsorption
• atrazine
• Freundlich equation
• Langmuir equation
• phosphate

Quantification of soil processes, such as adsorption, is needed for predicting the fate of agricultural chemicals in soils. Adsorption is affected by soil properties, which vary with depth. We conducted a laboratory study to determine the influence of soil depth on the adsorption of an organic solute (atrazine) in both allophanic and non-allophanic soils, and an inorganic solute (phosphate) in two non-allophanic soils. Adsorption isotherms of atrazine and phosphate were determined using C-14-labelled atrazine and KH2PO4, respectively, in batch equilibrium. The adsorption isotherms for atrazine were almost linear, and adequately described by the Freundlich equation. For phosphate the adsorption isotherms exhibited substantially more curvature and were best described by the Langmuir equation for one of the soils. Generally, adsorption of both solutes decreased with depth. While atrazine adsorption appeared related to such factors as percentage clay content, total C, cation exchange capacity (CEC), and surface area, no similar relationships appeared apparent for phosphate adsorption.

• 出版日期2003-6