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Potassium and Rubidium Adsorption and Diffusion in Soil
Author(s) -
Baligar V. C.,
Barber S. A.
Publication year - 1978
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1978.03615995004200020008x
Subject(s) - rubidium , soil water , adsorption , chemistry , potassium , selectivity , cation exchange capacity , diffusion , ion exchange , alkali metal , inorganic chemistry , soil ph , environmental chemistry , soil science , ion , catalysis , geology , organic chemistry , physics , thermodynamics
Uptake of cations by plant roots growing in soil is believed to be influenced by the relative adsorption strengths of cations by soil exchange sites. The adsorption of K and Rb by four soils was investigated to determine the differences in adsorption of K and Rb which may occur and how they are affected by soil properties with the view of using this information to evaluate the uptake mechanisms for K and Rb by plant roots growing in soil. Rubidium was adsorbed preferentially to K by all four soils. Selectivity coefficient k Rb/K , indicating the size of the effect ranged from 1.9 to 4.4. Adding K decreased k Rb/K , increased the amount of nonexchangeable Rb, and decreased exchangeable Rb. There was a negative correlation ( r 2 = 0.78) between exchangeable K in the soil and k Rb/K . The level of K in the soil had a greater effect on k Rb/K than varying types of exchange sites present due to differences in clay and amounts of organic matter in the four soils investigated. The size of the selectivity coefficient indicated that the difference between K/Rb ratios in the solution and exchange phases of these soils used and differences between soils made them suitable for use in plant uptake studies of the mechanisms of K and Rb uptake.