Ion Diffusion in Soils As Related to Physical and Chemical Properties
1985
Skogley, E. O. | Schaff, B. E.
Ion diffusion to plant roots is known to be a major factor influencing availability of certain nutrients in the soil. Diffusion of K⁺, Ca²⁺, and Mg²⁺ from soil to a H-saturated ion exchange resin sink was measured for 20 agricultural surface soils (18 from Montana and two from Iowa) to investigate the relationship between diffusion and selected chemical and physical soil properties. The soils were moistened to a tension of 0.1 mPa and packed into cylinders to a bulk density of 1.25 Mg m⁻³. Cylinders were placed in temperature-controlled chambers at 5 or 30°C and ion diffusion into an ionexchange resin sink was measured after 96 h. Diffusion of K⁺, Ca²⁺, and Mg²⁺ was significantly different between soils and at the two temperatures, and there was a significant soil times temperature interaction. Regression of 41 independent soil physical and chemical characteristics against amount of K⁺, Ca²⁺, and Mg²⁺ in the resin revealed several soil chemical and physical properties that were significantly related to ion diffusion. Values for NH₄OAC extractable ions were not as highly correlated to diffusion of these ions as were several other factors.
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