Electrode method for the determination of soil electrical conductivity (2)

Six, analysis and testing

(1) Instrument calibration

Knowing the conductivity cell constant of the electrode, adjust the instrument according to the instruction manual of the conductivity meter, and calibrate the instrument with a potassium chloride standard solution whose conductivity is similar to that of the sample extract

(2) Determination

Rinse the electrode several times with water, and then rinse the electrode with the extraction solution to be tested

Seven, calculation and presentation of results

Obtain the conductivity value of the extract directly from the reading on the instrument, and the unit is expressed in mS/m

8.

(1) A laboratory blank should be measured for each batch of samples, and the blank conductivity value should not exceed 1mS/m

(2) Before each batch of samples is measured (or every month), the instrument needs to be calibrated with potassium chloride standard solution.

(3) One parallel sample should be made for every 10 samples or every batch (less than 10 samples/batch)

Table 9-2 Repeatability of conductivity value

Nine, matters needing attention

(1) The potassium chloride standard solution should be transferred to a sealed polyethylene bottle for storage.

(2) When there are small bubbles on the electrode surface, tap the vibrating container to remove them to avoid measurement errors

(3) When extracting samples, avoid violent shaking

(4) After the sample is extracted, it should be determined in time

Related Links: Electrode Method for Measuring Soil Conductivity (1)