What is Potassium Meq/L and Potassium ppm?
- Potassium Meq/L (milliequivalents per liter): This measures the concentration of potassium ions in water or soil solution based on their chemical activity.
- Potassium ppm (parts per million): This is the amount of potassium in milligrams per liter (mg/L), often easier to understand because it represents the actual weight of potassium.
Why convert Meq/L to ppm?
Sometimes, test results or recommendations give potassium in Meq/L, but you might want the amount in ppm to compare with fertilizer labels or soil requirements.
How to convert Potassium from Meq/L to ppm?
To convert potassium from Meq/L to ppm, use the following formula:
Potassium (ppm)=Potassium (Meq/L)×Equivalent weight of Potassium (mg/Meq)
What is the equivalent weight of Potassium?
- Potassium (K) atomic weight = 39 g/mol
- Charge of potassium ion (K⁺) = 1 (since it has one positive charge)
- Equivalent weight = atomic weight ÷ charge = 39 mg/Meq
Step-by-step example:
If you have 2 Meq/L of potassium, then:
Potassium (ppm)=2×39=78 ppm
This means 2 Meq/L of potassium is equal to 78 ppm.
Summary table
| Potassium (Meq/L) | Potassium (ppm) |
|---|---|
| 1 | 39 |
| 2 | 78 |
| 3 | 117 |
| 4 | 156 |
You can find more agriculture conversion calculators here.