Units!?!

[Alfybe]

Hello to everyone
Novice question.
I read here and there that we quantify the different substances in units
I guess it's a relative measure, but if it's ... about what?

Thank you for enlightening my lantern

Alfybe

[sen-no-sen]

Hello and welcome to the forum.
Could you at least develop your question?
You talk about substance, what are you referring to? To the elements (in the sense of the periodic table of Mendeleyev), to the various resources (, Wood, oil, gas, coal), to energy?

[sicetaitsimple]

Rather nitrogen units, P, K, no?

[Forhorse]

So that the units I never understood anything. Yet I worked in agriculture, on fertilizer spreaders and more, but it was not my part at all. The units are a peasant thing, for me (and the machine) they translated in Kg / ha according to the fertilizer.

[Alfybe]

Ah, that's what I thought, it's not for me that it's not obvious.

For me quantification implies a prior definition. Kg, meter, volume are unambiguously defined.
In the kitchen, if you make a cake 4 quarters, the unit is relative, if you sell 100 € (because it's a big cake) it's quantitative.
When we speak agriculture we speak of unit of nitrogen (to take only this one) but what is the definition of unity? is it quantitative or relative?

But maybe I'm not clear?

Thank you

[sicetaitsimple]

But maybe I'm not clear?

Not really!
Okay, are we talking about "units" in agriculture? Yes No?
Then give an example of a writing that you did not understand by explaining why, it may be easier.

[Forhorse]

Yes, we are talking about fertilizer units in agriculture.
Like a farmer will tell you "in this field I put 15 units of nitrogen" but the question is what this "unit" corresponds to.
The answer must probably be on the net with the right keywords.

[Alfybe]

Let's stay positive friends (if I may allow myself),
If I ask the question, it is because I have searched, that I am still looking for ... and that I have not (yet) found

It would seem that the term unit is used to designate the% of specific matter contained in a total quantity of material brought
This is consistent as long as we stay below 100 otherwise it is not the correct definition, or the assertion is false.
It seems to me to have already read / heard figures> 100 so doubt!

[Ahmed]

Since a unit of nutrient element is equal to 1 kg of this element, the unit of fertilizing material therefore relates to the useful fraction of the type of fertilizer and thus makes it possible to calculate with a simple rule of three the total quantity of raw product. which must be spread, whatever the various formulations.
For example, complete fertilizer 12-12-17 contains 12% N (nitrogen), 12 P (phosphorus) and 17% K (potash), other different formulations are possible, but thanks to the it is possible to know how much to spread and what type of formulation to choose ...

[Alfybe]

Thank you Ahmed, you confirm what I formulated in the previous post.

However, I have already read 240 units (I will look for the source) which makes this explanation a little 'lame'
because it can only be understood by values ​​<100 (100 being then pure matter)