Fertility raising if potatoes grown without water

Issue description

If potato farm runs out of water, then potatoes are still maturing, although yield is falling. However and surprisingly, this is raising farm fertility!
It seems that game treat the land as if potatoes are not growing on it.

Expected behavior

Since plants can mature even without water (this was a controversial decision), this should also consume fertility.

Reproduction steps

1. Load attached save and open properties of the farm in center of view
2. Note: There is a drought counter on
3. Note: There is a duration counter showing that potatoes are maturing (and yield is falling)
4. Run that game and observe, that Soil Fertility is slowly going up, while it should go down
5. After the rain, Soil Fertility will go down, correctly

Game version

v0.4.12c

Attachments

fertility_up.save

Files not imported: fertility_up.save

Was able to reproduce. Maybe a dev can chime in here but I'm assuming that the fertility is raising because the plants are no longer growing.