Bluelab Soil pH Meter - Manual (Page 8)

English
8
5.0 Measuring the pH value
Once the Bluelab Soil pH Meter has been set up and calibrated, using it to measure a pH value
involves using the Bluelab Soil pH Probe, the green dibber/auger, a soil/media sample and
button functions. NOTE: The soil pH probe tip must not have dried out. If it has dried, soak the soil
pH probe in tap water for one hour prior to taking a measurement.
Remove the top 5 cm / 2 in. from the surface of the sample area.
Insert the dibber/auger into the sample to a depth of about 20 cm / 8 in. and remove.
If the soil/media is dry, moisten with a small amount of distilled water.
Remove the storage cap and insert the soil pH probe to the same depth ensuring the
probe end makes proper contact with the soil.
Turn the soil pH meter on.
Wait for the reading displayed on the soil pH meter to stablize to a constant value. This
can take up to four minutes. Record the reading.
Remove the soil pH probe from the soil/media and wash the soil pH probe tip under fresh
running water (not distilled) to remove any remaining soil residue.
Repeat the procedure in different locations and take the average of the measured data as
the pH level is representative of the sample area.
If the soil pH meter turns off while taking a measurement, simply press the power button
to turn the soil pH meter back on and continue with your measurement.
Store the soil pH probe between measurements. See section 10.0.
6.0 Measuring soil solution pH value
The greatest source of error in soil analysis comes during sample collection. An effort should be
made to ensure each sample properly represents the area being sampled.
• The readings taken with this method could be higher than those taken by other methods
• Consistency of the method used is important to be able to compare sets of results
• The accuracy of this method cannot be guaranteed because of the variables involved
• The results should be viewed as ‘indicative’ rather than ‘absolute’
Collection of sample
Sample in a zig-zag pattern across the required area.
Remove 15 mm / 5/8 in. of top soil before sampling at a depth of 150 mm / 6 in.
Mix all collected samples together thoroughly.
Allow to dry in the air or in an oven at 40 °C / 104 °F.
Weigh out 20 g / 0.7 oz of the collected soil into a 150 ml / 5 fl oz plastic sample jar.
Sample preparation
Add 100 ml / 3 fl oz of distilled or deionised water, screw lid on tightly.
Shake continuously for 5 minutes. Leave overnight and shake again the next morning.
Allow to settle for 15 minutes after shaking and strain sample into clean measuring cup.
Take pH readings as follows:
Remove the storage cap and insert the soil pH probe tip into the soil solution sample.
Turn the soil pH meter on.
Wait for the reading displayed on the soil pH meter to stablize to a constant value. This
can take up to four minutes. Record the reading.
Remove the soil pH probe from the soil solution and wash the soil pH probe tip under
fresh running water (not distilled) to remove any possible soil residue.
If the soil pH meter turns off while taking a measurement, simply press the power button
to turn the soil pH meter back on and continue with your measurement.
Store soil pH probe between measurements
See section 10.0.
1
2
3
4
1
1 1
1
1
5
2
2
2
6
7
8
9
10
3
3
3
4
4
5
5