What may form in a large body of water such as a lake or ocean, is a delta
Fertile soil and mild climate!
Substinence farming is farming food that is just enough to live off of. You don't sell substinence crops.
Commercial farming is growing food to sustain you, and having enough left over to sell.
In both, you grow food and you keep some (or all) for yourself.
Maybe size or mass .........
