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fertilizer anaylsis

Discussion in 'Fertilizer Application' started by bug-guy, Jun 7, 2014.

  1. bug-guy

    bug-guy LawnSite Senior Member
    Posts: 972

    a bag of 24-2-11 means there is 24+2+11 = 37 lbs of N,P,K in 100lbs the rest of the weight is minors and then a filler. so a 50 lb bag will get you 12k at 1 lb of N per 1000 ft sq.
    my question is a bag of 21-0-0 weighing 50 lbs where is the filler if it's all soluble product.
  2. bug-guy

    bug-guy LawnSite Senior Member
    Posts: 972

    is the rest sulfur??
  3. WenzelOSLLC

    WenzelOSLLC LawnSite Senior Member
    Posts: 709

    Not 100% positive but I think its usually an inert carrier (talking about granular). Meaning the 'filler' has no value what so ever if you were to analyze it. No NPK value, no MINORS, nothing that can be used by plants.

    Not the best example but think of koolaid. You can't easily drink/eat the powder. You add the 'nutrients' to the water (no nutritional/flavor value) so it can be 'applied' to your mouth.
  4. ShaneW

    ShaneW LawnSite Member
    Posts: 63

    21-0-0 is 100% ammonium sulfate. There is no filler. Nitrogen makes up 21% of the ammonium sulfate compound (NH4 + SO2).

    Ever wonder why you can't have a bag of 33-33-33?
  5. bug-guy

    bug-guy LawnSite Senior Member
    Posts: 972

    how do you explain the weight of the bag if 21 lbs of N in 100 lbs
  6. Trees Too

    Trees Too LawnSite Silver Member
    Posts: 2,511

    Check out this link. You may find the info helpful...

  7. ShaneW

    ShaneW LawnSite Member
    Posts: 63

    The analysis is 21-0-0 because 21% of the weight of the bag is nitrogen. However, we aren't dealing with pure nitrogen, we're dealing with ammonium sulfate. Nitrogen only makes up 21% of the compound (NH4+So2-). The rest is hydrogen, oxygen and sulfur.

    Another example: a bag of straight urea would be 46-0-0, even though the bag is 100% urea. Urea is the nitrogen source, but urea isn't 100% nitrogen. Otherwise, the analysis would be 100-0-0. Urea is CONH2. Only 46% of the compound is nitrogen. The rest is made up of carbon, oxygen and hydrogen.
  8. bug-guy

    bug-guy LawnSite Senior Member
    Posts: 972

    that makes more sense but to clarify 21-0-0 is 21 % N per 100 lbs all analysis is base off 100 lbs

    so a 50 # bag is 10.5% which is 10.5 k for 1# of n per k or 21 K for 1/2 lb per k as usually used in a liq app
  9. ShaneW

    ShaneW LawnSite Member
    Posts: 63


    21% of 50 pounds is 10.5 pounds, not 10.5%.

    21-0-0 is 21% N per 100 lbs, 150 lbs, 1 lb or a million pounds. I'm not sure you understand the concept of percentages. Sorry.

    Here's another way of looking at it. Maybe this will make more sense.

    Suppose you had a fertilizer that was 20% nitrogen, in a 10-pound bag. That would mean 2 lbs of N in the bag (20% of 10, or 0.2 x 10). What if the same fertilizer was in a 50-pound bag? Would that mean you now have 100% N? Of course not. It's still 20% N regardless of the total weight.
  10. bug-guy

    bug-guy LawnSite Senior Member
    Posts: 972

    sorry meant # instead of %

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