Convert Potassium ppm to Potassium Meq/100g


What is Potassium ppm and Potassium Meq/100g?

  • Potassium ppm (mg/kg) means the amount of potassium in milligrams per kilogram of soil. It’s like saying “how many milligrams of potassium are there in one kilogram of soil.”
  • Potassium Meq/100g means the amount of potassium in milliequivalents per 100 grams of soil. This unit helps understand how much potassium is available for plants chemically.

Why convert ppm to Meq/100g?

  • ppm tells you the weight amount, but Meq/100g tells you the chemical activity or nutrient availability in the soil.
  • Farmers and soil experts use Meq/100g to decide fertilizer needs.

How to convert Potassium ppm to Potassium Meq/100g?

Step 1: Understand the units

  • 1 ppm = 1 mg/kg of soil
  • Since 1 kg = 1000 g, ppm can be converted to mg/100 g by dividing by 10:

Potassium (mg/100g)=Potassium (ppm)/10

Step 2: Calculate milliequivalents (Meq)

  • The formula for converting mg to Meq is:

Meq=mg/atomic weight/valence

  • For Potassium (K), atomic weight = 39 mg/mmol, valence = 1
    Therefore,

Meq=mg/39

Step 3: Combine both steps

Potassium (Meq/100g)=Potassium (ppm)/10/39=Potassium (ppm)/390

Final formula:

Potassium (Meq/100g)=Potassium (ppm)/390

Example:

If your soil test shows 195 ppm Potassium,

Potassium (Meq/100g)=195/390=0.5 Meq/100g

You can find more agriculture conversion calculators here.