Is crop rotation actually necessary?

Is crop rotation necessary? I don't see any adverse effects from not rotating crops. I started this game on Easy. Is this feature not added into the game, or is it only necessary on harder settings?


As of 7/3/2014 according to the banished wiki:

http://banished-wiki.com/wiki/Farming

"Farming can be considered a sustainable method of obtaining food for your citizens, though farming for many seasons in one place will ruin the soil.[1] Though, the developer has confirmed that soil degradation has not been implemented."

In other words, no, at the moment it is not necessary