Soil pH, Liming, and Liming Materials

Weigh 10 g air-dried <10-mesh-sieved (2-mm) soil into a cup. Pipette 10 mL water into the cup and mix thoroughly for 5 min with a glass rod or mechanical stirrer. Let the soil-water suspension stand for 30 min. Perform pH measurement at 20 to 25 ° C (68 to 77 ° F). Before analysis, stir the soil-water suspension with glass rod or mechanical stirrer. Insert electrodes of calibrated pH meter into the soil-water slurry so that the electrode tips are at the soil-water interface; swirl soil-water suspension slightly. Read pH immediately (after 30 to 60 sec) to the nearest 0.1 unit.