If you describe land as arable, it means that something can grow there. If you're looking to raise crops, you better find yourself a patch of arable land.
Arable has its Latin roots in the word arare, which means "to plow." Arable soil is ground that can be plowed and cultivated. Chances are — if you are using the word arable, then either the word land or the word soil is following it; however, you might also see the phrase "arable crops" — meaning those crops that are able to be grown on arable land.