Soil pH is a basic soil parameter, since many processes in the soil depend on it, such as the growth and development of plants. Therefore, the monitoring of soil pH is very important. In this paper the values of soil pH are obtained by measurement of the samples in three media: H2O, KCl and CaCl2. The sampling was conducted at 18 locations on 11 soil types and 15 lower systematic units. The aim of this work was to establish functional connections between the pH values in all three media.
Repeatability of measurement expressed through the relative standard deviation, ranged from 0.21% to 3.87% in the H2O suspension, from 0.19% to 7.74% in the KCl suspension and from 0.25% to 4.19% in the CaCl2 suspension. Correlation coefficients varied in the classes: strong, very strong and absolute. The correlation coefficients for all measured samples were: r=0.96 for the pH KCl/H2O; r=0.97 for the pH KCl/CaCl2 and r=0.99 for the pH H2O/CaCl2 (absolute correlation). The correlation coefficients determined in the acid soils were: r=0.97 for the pH KCl/CaCl2 and pH H2O/CaCl2; r= 0.91 for the pH KCl/ H2O (absolute correlation). In the neutral soils, the correlation coefficient for the pH KCl/CaCl2 was r=0.69 (strong correlation), correlation coefficient for the pH KCl/H2O was r=0.80 (very strong correlation) and the correlation coefficient for the pH H2O/CaCl2 was r=0.92 (absolute correlation). In the alkaline soils, the correlation coefficient for the pH KCl/CaCl2 and pH KCl/H2O was r=0.66 (strong correlation), and correlation coefficient for the pH H2O/CaCl2 was r=0.88 (very strong correlation).
The existence of alleged functional connections through this work has been proven with very high significance.

soil pH; soil type; Croatia

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia