Measurement & Experimental Science
pH/EC Calibration & Measurement Quality
pH and EC values are only useful when the meter, calibration, sampling method, temperature context, and sample handling are trustworthy.
Key concepts
- Calibration checks instrument response against known standards
- pH electrodes require appropriate storage and maintenance
- EC reflects ionic conductivity, not the identity of individual nutrients
- Different sampling methods can produce different root-zone values
What to measure or observe
- Calibrate at a documented frequency
- Use fresh standards and clean containers
- Record sampling method and temperature context
- Rinse probes appropriately between samples
Common mistakes
- Treating an uncalibrated meter as precise
- Storing a pH electrode dry
- Comparing runoff, slurry, and direct-media readings as if they are identical methods
- Using EC to infer exact nutrient composition
Visuals this lesson still needs
- Calibration workflow
- pH electrode care diagram
- Sampling-method comparison
- EC interpretation graphic