Ishak, Cek Fauziah and I., Jamilah and Syed Rastan, Syed Omar (1997) An Evaluation of Cation Exchange Capacity Methods for Acid Tropical Soils. Pertanika Journal of Tropical Agricultural Science, 20 (2/3). pp. 113-119. ISSN 0126-6128
The cation exchange capacity (GEC) of soil is an important criteria for assessing soil fertility beside its use in soil classification. Seven methods, namely, (1) BaCl2 - triethanolamine of BaCl2 - TEA (PH 8.2), (2) NH40Ac (PH 7.0) - leaching, (3) NH40Ac (PH 7.0) - shaking, (4) compulsive exchange method of Gillman (1979) (GECcd, (5) modified compulsive exchange method of Gillman (1986) (CEC3, (6) Summation of Ca from method 5 with 1 M NH4 NO3 exchangeable Al (CECtotal and (7) summation of NH40Ac (PH 7.0) exchangeable bases with 1 M KCl exchangeable Al (CECsum) were used to determine and compare the CEC values of five acid tropical soils. All methods gave different CEC values which followed the order BaCl2 - TEA> NH40Ac shaking = NH40Ac leaching> CECsum = CECto tal > CECCE = CECB• Methods with pH conditions close to field situations gave much lower CEC values than the buffered methods. The buffered methods generate charge on the variable-charge colloids, thus resulting in inflated CEC values, while the unbuffered methods do not. There is a high correlation between BaCl2 - TEA and NH40Ac (PH 7. 0) leaching method; CECCE and CECsum; and, CECB and CECtotal Amongst the methods evaluated, the NH40Ac (PH 7.0) leaching is recommended in routine soil analyses for classification purposes while CECsum is recommended for agronomic evaluation.
|Keyword:||CEC, acid tropical soils, variable-charge soils, correlation study|
|Faculty or Institute:||Faculty of Agriculture|
|Publisher:||Universiti Putra Malaysia Press|
|Deposited By:||Nasirah Abu Samah|
|Deposited On:||30 Nov 2009 06:53|
|Last Modified:||27 May 2013 07:09|
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