A Critical Study of the BaCl2-Triethanolamine and the Ammonium Acetate Methods for Determining the Exchangeable Hydrogen Content of Soils1
- Michael Peech,
- R. L. Cowan and
- J. H. Baker2
A critical study of Mehlich's BaCl2-triethanolamine method for determining the exchangeable hydrogen in soils has led to a modification of the method which not only is simpler and more reproducible but gives results that are in better agreement with those obtained by the residual carbonate method. The buffer and the replacing solution of the original method have been replaced by a single extracting solution which consists of 0.5N BaCl2 and 0.055N triethanolamine neutralized to pH 8.0 with HCl.
The results obtained by the proposed method were also compared with those given by substracting the sum of the exchangeable metal ions from the amount of adsorbed ammonium as determined by the ammonium acetate (NH4OAc) method. The low results obtained by the NH4OAc method could not be attributed to fixation of the ammonium ion but were found to be due to loss of some ammoniated organic constituent upon washing the soil with 95% ethyl alcohol. Substitution of isopropyl alcohol for ethyl alcohol in washing out the excess of NH4OAc gave results for exchangeable hydrogen that were in excellent agreement with those obtained by the proposed BaCl2-triethanolamine and the residual carbonate methods.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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