Titration of Acid Soils

Seven acid soils containing varied cation exchange materials were studied by means of conductometric and potentiometric titrations with Ba(OH) 2 , NaOH, Na 2 B 4 O 7 , and NaOAc, and extractions with KCl, NH 4 OAc (pH 4.8), and BaCl 2 ‐triethanolamine (pH 8.3). Generally consistent results were obtained when the aluminate reaction was considered for titrations with strong bases. The extent of the aluminate reaction for exchangeable interlayer Al 3+ apparently depends on the exchange of Al 3+ by the base. Thus, the low values in conductometric titrations with NaOH compared to Ba(OH) 2 are explained on the basis of the poorer exchange of Al 3+ by Na + . Titrations with NaOAc indicate that only a cat clay soil contained strong acid type exchangeable H + , although four of the other soils contained about 20 meq/100g of Al 3+ exchangeable by KCl.