Why did the struggle for rich farmland affect the colonists in Virginia?

Because with out land men could not vote, without land they had to either work for wealthy farmers or move to inland to find land.
The struggle for rich farmland affected the colonists in Virginia because if you didn't own a piece of land, you lost the right to vote. Also, without the land, they were unable to plant your own crops, and you would be forced to move on to a wealthy landowner's farm and work for them.