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Cation Exchange Capacity and Exchangeable Aluminum in Natal Oxisols
Author(s) -
Reeve N. G.,
Sumner M. E.
Publication year - 1971
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/sssaj1971.03615995003500010017x
Subject(s) - oxisol , cation exchange capacity , chemistry , soil water , salt (chemistry) , electrolyte , environmental chemistry , soil science , environmental science , electrode
Positive charges in acid soils reduce CEC at low electrolyte concentration probably by double layer interaction. The resultant net ECE (determined by washing soil free of salt with water) is the effective CEC under field conditions and the difference between net CEC and exchangeable bases is accordingly a convenient measure of exchangeable Al. A reaction scheme is proposed which relates the large pool of nonexchangeable Al (extractable with 1 N NH 4 OA c ‐pH4) in these soils to the relatively small amounts of exchangeable Al; this reaction scheme is governed primarily by net CEC and exchangeable bases rather than by pH.