ASTM D2976-71(2004)

1.1 This test method covers the electrometric measurement of the pH of peat materials. It is a means of expressing the degree of acidity or alkalinity of peat material suspended in water and 0.01 M calcium chloride solution.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

pH measurements are made in water and in calcium chloride solution because the pH readings in water can be modified by salts, such as fertilizer material, whereas the observed pH in calcium chloride solution is virtually independent of the initial amount of salts present in the soil. pH values obtained in calcium chloride solution usually run about a 0.5 to 0.8 pH unit lower than measurements in water due to release of more hydrogen ions by cation exchange.