Methods for studying replaceable bases in calcareous soils
1929
Burgess, P.S.
The need of methods for the accurate determination of replaceable bases in calcareous soils is pointed out, and some of the faults of the earlier procedures, when applied to soils containing CaCO3, are discussed. The method which is proposed for the quantitative determination of replaceable bases in calcareous soils employs alcoholic salt solutions as the displacing agents. We prefer 0.1 N BaCl2 in 68% ethyl alcohol. Percolation, rather than shaking with subsequent filtration, is advocated where large numbers of determinations are to be made. The alcohol is evaporated, the residue is taken up in water and made up to volume, the excess Ba is precipitated as the chromate where Ca and Mg are to be determined or as the sulfate where Na and K are sought. Subsequently, the bases are separated by appropriate methods. Where "alkali salts" are present, these are removed by leaching with pure water before the soils are treated with the replacing solutions.
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