TEST METHOD: pH of soils
Revised: 3 June 2002
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|Calibrate the meter following the directions in the pH meter manufacturer's manual.||Out of date calibration solution.||Date calibration solution containers when opened and replace after the specified time (see label for details).|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.|
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