Convert Calcium ppm to Calcium Meq/100g


What is Calcium ppm and Calcium Meq/100g?

  • Calcium ppm means “parts per million” — it tells you how much calcium is in one million parts of soil or water. For example, 100 ppm means 100 parts of calcium in a million parts of soil.

  • Calcium Meq/100g means “milliequivalents per 100 grams.” It measures the amount of calcium in soil based on its chemical charge and weight, which is important for understanding soil fertility and nutrient availability.

Why convert Calcium ppm to Meq/100g?

  • Farmers often test soil for calcium in ppm, but soil chemistry and plant nutrition use Meq/100g to decide how much lime or fertilizer to apply.
  • Meq/100g helps understand the nutrient’s effect on soil pH and nutrient balance.

How to convert Calcium from ppm to Meq/100g?

  1. Know the formula:

Calcium Meq/100g=Calcium ppmEquivalent weight of Calcium×10

  1. Equivalent weight of Calcium:
  • Atomic weight of Calcium (Ca) = 40 g/mol
  • Calcium ion charge = +2
  • Equivalent weight = Atomic weight / Charge = 40 / 2 = 20
  1. Apply the formula:

Calcium Meq/100g=Calcium ppm/20×10=Calcium ppm/200

Example:

If your soil test shows 400 ppm Calcium:

Calcium Meq/100g=400/200=2 Meq/100g

Summary:

Step Action Formula
1 Find Calcium ppm from test Given
2 Divide ppm by 200 Meq/100g = ppm ÷ 200
3 Get Calcium Meq/100g value Use for soil nutrient plans

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