Hey Willem, you Dutch too???
Yes this is the Depo (starting government) penalty anything producing more than 2 on any one tile gets a -1 penaly!
So the Irrigated grass = 2+1-1 = 2, no bug....
The wheat tho is a bonus food (+2) so...
Grass (2) + Wheat (2) + Irrigations (+1) - Penalty (1) = 4 food
Since it gets the penalty right away anyway (2+2-1 = 3) the irrigating does help
General rule: Mine grass, Irrigate "brown"
EXCEPT: Bonus grasslands like the wheats, Irrigate them!
Together with the Agriculture trait, BANG.
OK Here goes.... STOP building the settler!
-Irrigate the Wheat (Just SW of Amsterdam). Then road it.
-Mine and road all the tiles directly around amsterdam.
-Build a Granary
-Chop the forest while building the Granary
-Build nothing but Settlers
This is known as a Settler factory and works because you get 5 extra food. You can grow 2 population and produce the settler in 4 turns. You have all but won this game!
Greetz from Amsterdam