With good Iowa or Illinois farmland you can expect 200 bushels of corn per acre or 60 bushels of soybeans. This land by the way will cost you approximately $7,183 per acre.
If you're interested in this topic you might consider attending the precision ag conference, the next one will be in 2018
http://www.precisionagvision.com/
Or your vegan community could move to downtown Detroit. Cheap fixer upper houses going for $1,000 with plenty of inexpensive land nearby. City brings the water right to you and with drip irrigation you can water your crop inexpensively. Lots of restaurants that want your produce and the largest farmers market in the country. http://www.easternmarket.com/
Lots of inexpensive, though untrained, help for minimum wage. Wide lightly travelled city streets and they just rewired the entire city with LED streetlights. Five million people live in the greater Detroit metropolitan area. You will have be proactive on crime, lots of web cams would be a wise investment. It wouldn't hurt to be armed, in fact the police chief recommends it! But without risks there wouldn't be the immense opportunities.