ABSTRACT

Soil pH is one of the most important and frequently measured chemical indicators for assessing the quality of a soil for plant growth and microbial activity. The pH is determined using different suspension media, soil-to-solution ratios, and soil moisture conditions; therefore, conversion equations are presented in this chapter 94among methods for pristine and cultivated organic soil materials in this chapter. The 0.01 M CaCl2 suspension was found to be the most reliable pH determination method against variations in moisture content and initial dewatering conditions of peat and moorsh materials. Compared with field-moist pristine peat materials, the air- or oven-drying procedure decreased pH values by 0.37 in water, 0.08 in 0.01 M CaCl2, and 0.08 in 1 M KCl. The Shoemaker-McLean-Pratt buffer pH value was sensitive to the moorsh-forming process. Whereas peat oven-drying (105°C) increased buffer pH by 0.22–0.25 pH unit, moorsh oven-drying decreased buffer pH by 0.12 pH unit compared with field-moist conditions. Change in buffer pH upon drying should be further investigated to quantify the intensity of the moorsh-forming process in organic soils after drainage and reclamation.