Enter the osmotic pressure of salt produced by the fertilizer  and the osmotic pressure of salt produced by NaNO3 into the Salt Index Calculator. The calculator will evaluate the Salt Index. 

Salt Index Formula

The following two example problems outline the steps and information needed to calculate the Salt Index.

SI = OPF / NaNO3

Variables:

  • SI is the Salt Index ( )
  • OPF is the osmotic pressure of the salt solution produced by the fertilizer  
  • NaNO3 is the osmotic pressure of salt produced by NaNO3 

How to Calculate Salt Index?

The following steps outline how to calculate the Salt Index.


  1. First, determine the osmotic pressure of salt solution produced by the fertilizer . 
  2. Next, determine the osmotic pressure of salt produced by NaNO3. 
  3. Next, gather the formula from above = SI = OPF / NaNO3.
  4. Finally, calculate the Salt Index.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

osmotic pressure of salt solution produced by the fertilizer  = 4

osmotic pressure of salt produced by NaNO3 = 3

SI = OPF / NaNO3 = ?