TEST METHOD: pH of soils
Revised: 3 June 2002
OVERVIEW
pH is an important indicator of soil conditions.
TASK SAFETY REQUIREMENTS
Safety boots are mandatory. Use appropriate PPE.
| SPECIFIC JOB STEPS | HAZARDS WITHIN THIS STEP | HAZARD CONTROL |
| This method uses the 1:5 soil/water extract, as considerable Australian data exists for this method. | ||
| Weigh 20 g of air-dried soil and place in a stirring jar. Add 100 mL of deionised water. Shake, stir or roll for one hour, then leave for 20-30 mins to settle. | A mechanical stirring device is not available. | Shake vigorously for 2 mins every 15 mins for two hours. |
| Decant the supernatant and test the pH as follows: | ||
| Calibrate the meter following the directions in the pH meter manufacturer's manual. | Out of date calibration solution. | Date calibration solution containers when opened and replace after the specified time (see label for details). |
| Insert the pH probe and temperature probe (if separate) into the water sample and stir gently. | ||
| Wait until the reading stabilises and record reading in the laboratory daybook. Report as: pH (1:5 soil water) on an air-dry basis. |