Convert Sodium Meq/100g to Sodium ppm


What is Sodium meq/100g and Sodium ppm?

  • Sodium meq/100g means how many milliequivalents (meq) of sodium are present in 100 grams of soil.
  • Sodium ppm means how many parts of sodium there are per million parts of soil. It’s like saying how many milligrams of sodium are in each kilogram of soil (because 1 ppm = 1 mg/kg).

Why convert Sodium meq/100g to ppm?

Farmers often get soil test results in meq/100g, but sometimes they need to know the amount in ppm to understand sodium levels better or compare with fertilizer recommendations.

How to convert Sodium meq/100g to ppm?

  1. Know the atomic weight of sodium (Na):
    Sodium has an atomic weight of 23 grams per mole.

  2. Understand what 1 meq means:

    • 1 equivalent (eq) is the amount of an element that reacts with 1 mole of hydrogen ions (H⁺).
    • Sodium ion (Na⁺) has a charge of +1, so 1 mole of Na = 1 equivalent.
    • 1 milliequivalent (meq) = 1/1000 equivalent.

  3. Calculate sodium weight in mg for 1 meq:

    • Atomic weight of Na = 23 g/mol.
    • 1 eq Na = 23 g = 23,000 mg.
    • Therefore, 1 meq Na = 23,000 mg / 1000 = 23 mg.

  4. Convert meq/100g soil to mg/kg soil (ppm):
    Since 100 g soil is 0.1 kg, multiply by 10 to get per kg basis:

    Sodium ppm=Sodium meq/100g×23×10=Sodium meq/100g×230

Final formula:

Sodium (ppm)=Sodium (meq/100g)×230

Example:

If your soil test shows Sodium = 2 meq/100g:

2 meq/100g×230=460 ppm

This means your soil has 460 ppm sodium.

You can find more agriculture conversion calculators here.