Question about fertilizer

[Phobos]

I don't understand the amount of fertilizer.
If a field with potatoes has an average soil fertility of 60%, do I only need 1x 40 fertilizer for 3 months to reach 100%? And at the next harvest again 1x 40 fertilizer?
Is there any way to calculate that?
I want to know roughly how much fertilizer I need to produce to fertilize all my fields.

How do you do that with the fertilizer?

[vokulnin]

From my limited knowledge, you can see how much fertility a crop use per minute when you select it (for exemple, in my save, a potato consume 10.5% of fertility per minute). A fertilizer (fertiliser 1 and 2) give you 2% of fertility per unit, so I think you will need slightly more than 5 unit per minute for that.

But then you also have the fertility natural regen that depend of your current level of fertiliy to take in account, and that I don't have much details about how it work. Also, if you don't rotate your crop, the game tell you it will consume extra fertility, but without giving any details.

So I hope it will at least help you to get a rought estimate of the needed fertiliser.

[SpeedDaemon]

It's a bit complicated... there are some equations on the Farming page of the wiki that can help figure it out if you need to plan ahead.

Keep in mind that farms regenerate fertility all the time (even while a crop is growing), proportionate to how far below 100% the fertility is. So, the fertility equilibrium is when it gets low enough that regeneration matches the current crop's usage.

When you set the fertility target, there will be a "fertility needed" listed on the interface. It should take that amount per month of organic fertilizer, or half that amount of fert I or II.

[Phobos]

Thanks for your tips. I took a closer look and observed the displays in the window and I think I now understand the missing % for soil moisture with the fertilizer