Methods of pH determination in calcareous soils: use of electrolytes and suspension effect
A. Al-Busaidi A B , P. Cookson B and T. Yamamoto AA Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori 680-0001, Japan.
B Department of Soil and Water Sciences, College of Agricultural and Marine Science, Sultan Qaboos University (SQU), PO Box 34 Al-Khod 123, Oman.
Australian Journal of Soil Research 43(4) 541-545 https://doi.org/10.1071/SR04102
Submitted: 29 June 2004 Accepted: 1 March 2005 Published: 30 June 2005
Abstract
Determination of pH assists in understanding many reactions that occur in soil. However, measured values of soil pH can be affected by the procedure used for determination and by a range of soil properties. In this study, pH was measured in different electrolytes [distilled water (pHw), 0.01 m CaCl2 (pHca), 1 m KCl (pHk), and 0.01 m BaCl2 (pHba)] with different soil : solution ratios (i.e. 1 : 1, 1 : 2.5, 1 : 5), the main objective being to study the influence of different electrolytes on the suspension effect of pH in calcareous soils.
Soil pH measured in water showed significant differences between different dilution ratios and was highly influenced by the ‘suspension effect’. Other electrolytes (CaCl2, KCl, BaCl2) were little affected by the suspension effect, giving approximately stable values when pH was measured with and without stirring. High soil salinity appeared to suppress any suspension effect in a manner similar to electrolytes when added to non-saline soils.
Additional keyword: calcium carbonate, salinity, dilution.
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