Units!?!

[izentrop]

Hello,
Gougueule is your friend https://www.afidol.org/forum/viewtopic.php?t=206

[Ahmed]

I have already read 240 units

I think you mix your feet in absolute values ​​and percentages ...
It simply means 240 kg / ha, so if you have, for example, nitrogen fertilizer 20% (so 20 kg of active ingredient for 100 kg total material), you must bring 1200 kg per hectare of this formulation ...

[Did67]

A little further clarification: if for nitrogen, a unit of nitrogen is indeed 1 kg of nitrogen (understood as pure, or "the chemical element nitrogen"), for P and K it gets worse!

Due to chemical methods of analysis still in its infancy when it was formulated, for P (Phosphorus) we count in P₂O₅ : a "unit of P" is therefore the quantity of P - chemical element phosphorus - contained in 1 kg of P₂O₅

And for K (potassium), we count in K₂O: one unit of K is "as much K - chemical element potassium - as there is in 1 kg of K₂O ".

And so in fact, in a fertilizer or an amendment there cannot be more than 100% of such an element - and often much less - because it is not the pure element that we are handling, but a very impure, containing other elements - for example in potassium chloride there is also chloride, which weighs but is useless! Or fillers (ammonium nitrate or ammonium nitrate is "packed" with inert powders).

On a field, you can, however, bring as many units as you want, provided you put the corresponding amount of fertilizer. It's a simple rule of three!

- A technical sheet tells you to bring 240 units of N / ha (so a quantity per surface); in short, the farmer will tell you that he puts 240 nitrogen units - between them, they understand each other ...
- you use an ammonitrate which contains 33,5% (it is obligatorily marked on the sachet)
- you just need to bring 240 / 0,335 = 716 kg of fertilizer (which therefore contains 33,5% of N, therefore 240 units) per ha of crop

It is rigorous: the% in the fertilizer does not exceed 100%, but the quantity per hectare corresponds to the needs of the plant, ie 240 units per ha of culture.

And if you cultivate 7 ha, logically, the quantity is multiplied by 7: a little more than 5 000 kg, or 5 t.

[Alfybe]

Thank you all, I knew that I would find a consistent answer here.
The use of quantification in several modes is confusing especially if they are mixed in the same purpose.
I am an electronics technician and in the field, the confusion between kW and kW / h is frequent, I suppose that it is the same principle.
Thank you to all

@did67
I sent you info about a conference (s) in Belgium in October and I'm afraid you've 'zapped' the message because I do not see any reaction.
For my comfort, do you want to follow up fairly quickly (positive or negative) because I have time constraints for the reservation of premises.
Thank you

[Did67]

Oh it's you !!!

I look at this with my wife and confirm you this weekend ...

PS: You will notice that not everyone appreciates our "coherent answers"!

[Alfybe]

Goods.

PS: You will notice that not everyone appreciates our "coherent answers"!

Yes, it is besides all the interest of your book which combines rigor and ecology.

See you soon ;-).

[Grelinette]

Just as an aside, always on the subject of units difficult to understand and to convert, in the agricultural environment one also speaks of CFU for feeding equines, and UFC means: "Horse forage unit". It is the unit of caloric intake given for a specific basic diet given in barley equivalent (a cer "ale.

So for horses (and probably also for other herbivores), we calculate the energy intake in CFUs but not in calories, even if there is a correspondence with calories.

Concretely, it is so difficult to convert because the equine diet, because it can be very varied (cereals, granulated feed, etc.) that often acts empirically!

Moreover, to make a link with the basic subject, for the food there is also the parameter of% of assimilation, namely the% of the part of energy contained in the food which will be assimilated 35 to 70% for forages, and 70 to 90% for concentrated feeds, not to mention equids themselves, which must have different assimilative capacities.

... and probably this notion of% assimilation must also be found with the different types of soil that receive the amounts of fertilizer!

[sicetaitsimple]

Thank you all, I knew that I would find a consistent answer here.

I'm coming after the battle, but I just wanted to flag a page from another forum that I had noticed one day and that seemed to me to be a good introduction about fertilizers (nutrients) and that addresses these issues of units:
https://www.aujardin.org/viewtopic.php?t=117805&start=

I send it to you, but I am not the editor, so I will not discuss it.

[Forhorse]

I am an electronics engineer and in the field, the confusion between kW and kW / h is frequent,

Ah it's ugly for an electronics engineer to write kW / h while it does not exist ... the real unit for the coup it's kWh

[Alfybe]

Thank you all, I knew that I would find a consistent answer here.

I'm coming after the battle, but I just wanted to flag a page from another forum that I had noticed one day and that seemed to me to be a good introduction about fertilizers (nutrients) and that addresses these issues of units:
https://www.aujardin.org/viewtopic.php?t=117805&start=

I send it to you, but I am not the editor, so I will not discuss it.

Thank you, I note it carefully