Also, to the point of being marginal ground, soil tests are needed to determine soil health, maybe do some diy percolating tests, ect; but there a hundreds of reasons this quarter section wasn't in production. It could have been tobacco crop, 40 years ago, and the market tanked; it could have been in a 25 year conservation easement, maybe kids moved off farm, they didn't have man power to run the whole 300 acres. It's also possible that it Is marginal, or better stated, marginal for a specific crop. Sandy soils on a wheat or corn operation might be seen as marginal but might make excellent peanut ground. Agriculture is a massively diverse term, and it could be anything from pine plantation, to cattle, vineyard, corn, hops, ect. Sure, there is some land that can't produce much of anything, but probably 95% of land, that recieves enough water can produce something. Heck, there are guys is Louisiana raising Elk for meat production, as well as for game farms. About 10 years ago, here in Fla, you saw more cotton fields then 25 years ago; 5 year old pines being plowed down for blueberries, ect. Trends, markets, and commodities change over time to meet local, national, and international demands.
Edit: that shifting in demand/commodities, ect also applies to solar farms, Argo tourism, corn mazes, farm to door meat, ect. If a land owner stays to stuck in "granddaddy planted beans and corn, so thats all we will ever do", that land owner will probably be the last generation of his line farming it. Same with, great granddaddy never cleared that woods, so it can't be worth it, it will stay woods forever.