While I agree with your general point, outside of course grain growing regions, there were too many things going in the '30s to ascribe the rural depopulation you note to just this.
Biggest example would be the federal government suppressing food production and trying to keep prices high, at the same time the same Department of Agriculture estimated 1/4 of the population was malnourished. As was confirmed by the WWII draft, and I've read that was one of the inputs into the Truman school lunch law.
As an extreme example, see Wickard v. Filburn where in 1942 the Supreme Court ruled the Federal government could prevent you from growing wheat on your own property for your own consumption.
Get back to the price supports, a big problem was an inability for all farmers/farms to make a living on what they could produce. Specialization meant it was much harder to try to provide for yourself everything you needed, and people responded to these incentives and opportunities in more urban areas, real ones at least once WWII production got started and the draft drained the manpower pool.
And of course a large part of this was increased mechanization, which pretty much never stopped replacing farm labor with machines. My parents are from farms and the Silent Generation, so they experienced the tail end of this. And they made very sure to "get off the farm", the work is brutal, a lot more so back then.
Grain-growing regions have grain, not food. Short term survival in oft-fantasized SHTF scenarios depends on easily accessible calories. A grain elevator full of maize is not accessible calories. Less so a cow. So while you're in the country trying to break in to a grain bin so you can chew on some raw millet, I'll be cowering (and crying) in my suburban basement waiting for the National Guard to set up a food distribution center close enough for me to fight my way to it with two mags of 9mm and a sharp stick.
See how absurd these discussions get?
BTW, I have family in a small Kansas town a with couple thousand people, four dipshit cops, roughly equal amounts of meth and ammo, and one giant grain elevator. If SHTF I bet you my mano&metate that they show up at my house in the city within days or weeks.
Although as Nuclear War Survival Skills (NWSS) points out, bundling three metal pipes together works a lot better.
Boil with water and you have edible gruel. Maybe not enough fat to keep children thriving (NWSS said that about wheat, at least), but that can wait a bit.
If you had bothered to read my previous post, you'd know that I won't have my mano or metate because I will have lost them both to YOU in a frivolous bet.
I'll look into those bundled pipes. You figure out how to fend off the co-op members when we try to break into their granary. They don't care much for city folk down there.
Biggest example would be the federal government suppressing food production and trying to keep prices high, at the same time the same Department of Agriculture estimated 1/4 of the population was malnourished. As was confirmed by the WWII draft, and I've read that was one of the inputs into the Truman school lunch law.
As an extreme example, see Wickard v. Filburn where in 1942 the Supreme Court ruled the Federal government could prevent you from growing wheat on your own property for your own consumption.
Get back to the price supports, a big problem was an inability for all farmers/farms to make a living on what they could produce. Specialization meant it was much harder to try to provide for yourself everything you needed, and people responded to these incentives and opportunities in more urban areas, real ones at least once WWII production got started and the draft drained the manpower pool.
And of course a large part of this was increased mechanization, which pretty much never stopped replacing farm labor with machines. My parents are from farms and the Silent Generation, so they experienced the tail end of this. And they made very sure to "get off the farm", the work is brutal, a lot more so back then.