Re: Can some one translate this for me please. all chemical
Andy,
It depends on who is doing the calculation and what frame of reference is being used. For our purposes, we don't bother to calculate the N due to NO3 (displayed as N-NO3) or the P due to Phosphate (P-PO4). We just use the NO3/PO4 concentrations and call it good.
Sometimes, biologists or chemists want to know the N contribution of NO3 because perhaps there are other sources of N in the sample being measured such as NH4, so they need to know the amount of N being contributed by the NO3 alone versus the N being contributed by the NH4.
This is just a simple calculation since the N is only 23% by weight of NO3. There are 3 Oxygen atoms for every Nitrogen in this ion. So Oxygen is 77% by weight. So if you see a number like 10ppm N-NO3 then 10ppm is only the Nitrogen concentration and is 23% of the total NO3 concentration. To find how much NO3 concentration was responsible for 10ppm of N you would do the following calculation:
10ppmN = 0.23*(NO3) =>
Divide by 0.23 to isolate NO3 => NO3=10ppmN/0.23 =>
NO3=43.5ppm
So it takes 43.5ppm of Nitrate to generate 10ppm of N from that Nitrate.
Instead of doing algebra every time, 1/0.23 (or punch this in on your calculator to get 4.35) becomes the conversion factor to change N-NO3ppm to simple NO3ppm, and conversely, multiply the NO3ppm by 0.23 to figure out how much Nppm there is.
You can do a similar computation with P-PO4 knowing that P is about 33% by weight of the PO4 molecule. So without slogging through the algebra again you can guess that the conversion factor is gonna be 1/0.33 or 3.0 depending on which direction you want to convert.
Again, since we dose the molecules NO3/PO4 and then let the plant figure out the algebra, we really don't care about N-NO3 or P-PO4 - but we can always figure it out if we need to.
Hope this helps.
Cheers,
just didn't know how to express it in words. well done. 
