Observation on Laboratory pH Measurement in Soil by Water, Calcium Chloride and Potassium Chloride Solution for Soils under Laboratory Study

Abstract

The experiment was conducted from April to September, 2021 at Chole District, Eastern Arsi Zone, to generate baseline information on soil pH measurements under routine laboratory analyses. The study evaluated soil pH in different electrolyte solutions and soil-to-solution ratios to establish relationships using statistical regression. A total of 55 surface soil samples (0–20 cm) collected from cultivated agricultural lands were analyzed. The relationships among pH measured in water (pH_H2O), 0.01 M CaCl₂ (pH_CaCl2), and 1 M KCl (pH_KCl) solutions were investigated following standard laboratory procedures. Soil pH is one of the most commonly measured soil properties and serves as an important indicator of soil quality, fertilizer recommendations, liming requirements, and biogeochemical processes in terrestrial ecosystems. The results showed that pH values measured in salt solutions were lower than those measured in water, with variations depending on the electrolyte solution used. The average pH CaCl₂ value was lower than pH H₂O by 0.85 ± 0.09 pH units, while pH KCl was lower than pH H₂O by 1.27±0.10 pH units. Linear regression analysis indicated strong relationships between pH_H2O and pH measured in electrolyte solutions. The correlation coefficients obtained were r=0.6355 for CaCl₂ and r=0.6239 for KCl solutions. The findings confirm that both CaCl₂ and KCl solutions are useful for soil pH determination and can provide reliable information for soil management and agricultural practices.