Determination of soil specific surface area by water vapor adsorption: I Drying of soil samples

Authors

• Raina Niskanen Department of Agricultural Chemistry, University of Helsinki, SF-00710 Helsinki, Finland
• Väinö Mäntylahti Viljavuuspalvelu Oy (Soil Analysis Service Ltd.), Vellikellontie 4, SF-00410 Helsinki, Finland

DOI: https://doi.org/10.23986/afsci.72248

Abstract

Drying of three mineral soil samples (clay content 4—58 %, organic carbon content 1—5 %) equilibrated at 75.5 % relative humidity was studied. The soils were dried in an oven at +50°C, +70°C and + 105°C for 4 and 8 hours and in a desiccator over pure concentrated H2SO4 and P2O5. Drying over desiccants for 8 hours removed less water than drying at + 50°C. Drying over desiccants for 3—7 days was as efficient as drying at +70°C, for 14—24 days as efficient as 4 hours of drying at + 105°C. Eight hours of drying at + 105°C seemed to be too drastic, because it caused a greater weight loss in the clay sample of 5 % organic carbon content than did prolonged desiccant-drying. Drying at + 70°Cremoved as much water from fine sand which contained 4 % clay as prolonged desiccant-drying.