Chemical Nutrients

[thaipan2000]

hello is't enyone know the numbers on the chemical nutrients bags ex 15-15-15,46-0-0.

[krauti]

hi taipan,

the three numbers mean in the order: Nitrogen/Phospate/Potassium. 46-0-0 is Urea, a fully nitrogenic fertilizer. check the web for further explanation.

best for you

krauti

[Scoop1]

Hi taipan, the number represents the amount of the particular nutrient in the mix,as a percentage, for example, Calcium Nitrate = 18.8% Calcium and 15.5 Nitrogen, what are you using it for , to fertilize what?

15-15 15 = 15% Nitrogen 15% Phosphorous 15% Potassium = NPK 15-15-15

Cheers

Scoop1

[WatersEdge]

It should be clarified a bit to say that the NPK numbers on the bag are

Weight Percent with

N

P205

K2O as the compounds weighed.

It gets a little confusion at first,

since those formulas don't exist in real life

They are just a method of describing what has developed over time in the fertilizer industry.

From there we have many actual chemical formulations,

which all are converted to the standard terminology.

For instance:

Urea 46-0-0 is chemical formula (NH2)2CO, which to manufacture is

Two Ammonia NH3 with One CO2, then a Water H20 is thrown out.

2NH3 + CO2 => (NH2)2CO + H2O

Nitrogen has atomic weight 14

Hydrogen 1

Carbon 12

Oxygen 16

So adding those constituents together to reach the Molecular weight of Urea

Two N @ 14 => 28

Four H 1 => 4

One C 12 => 12

One O 16 => 16

=============================

Molecular Weight 60

The Percentage then of N is 28/60 => 0.4666 => 46.7%

By identifying the chemical compounds mixed into any fertilizer formula,

you can derive the NPK number from it.

A couple of years ago there was a strong thread on fertilizers here on the Farm Forum.

There is an Excel fertilizer calculator that I put up at that time

which demonstrates these calculations and

enables cost comparisons of various fertilizer formulas.

Please note that in the case of Phosphorous P and Potassium K,

there is a big difference between the

P2O5 Phosphate weight and the P Elemental weight and the

K2O Potash K Elemental

In some calculations Elemental weight is used,

so you need to determine if the writer means Compound or Elemental weight.

It's meant to be confusing so that Fertilizer Salesman can hold something over you.

But it's not actually all that bad after you get into it.

Nothing like a good spreadsheet calculator to make it all clear.

[andycrosby]

<deleted> I BET YOUR GLAD YOU ASKED