They don't, because they don't actually know when easter was, so they declared it to be the last sunday of march.
That they were upset and willing to do anything to lower the tax, them trying to tax the colonists like they hadn't before was like "preaching to the dead" as they put it because they weren't going to do what they said
"Fertile," as in fertile soil or fertile land, means that the soil and land is rich in nutrients for plants, and therefore is good for farming crops.
