@jawollbrink - a couple years ago, I spent many hours investigating farmland as an investment. It seemed like such a solid approach, since it's so 'hand-off' for the land owner, and they can just lease the land out to a farmer, who bears all the risk.
The problem I found was that it's very, VERY hard to find good deals on farmland (i.e. - an investment that has positive cash flow). It's a completely different ballgame than buying small, residential lots for 10% - 30% of market value. Unlike a residential lot that serves very little use and requires annual property taxes with no cash flow, a good piece of farmland is actually making money for the owner and requiring virtually no effort from them, so what reason would they have to sell it for such a huge discount?
I think what your grandfather did in the 80s is really the most sensible way to make it work... by purchasing the land when the market is depressed. Right now, this isn't really a thing. Most of the property owners I talked to had inherited their land from their parents and grandparents, and it had been farmed by their family for generations. Back when it was originally purchased (generations ago) it was a different world, and many of the people who own it now are actually working the ground every year.
Of course, I'm sure there are exceptions. There is probably the occasional one-in-a-million deal on farmland, but they're very hard to find.
I was also surprised to learn that the market values of farmland do not move in tandem with the market values of housing, they're like two completely separate things. If anything, it's more affected by the value of commodities, so it really is like a whole new type of real estate you have to learn and understand (and obviously, people who are actually working in the agricultural industry understand it the best).
I did actually put together a few comprehensive blog posts from what I had learned, you might find these helpful:
After realizing how big the barriers to entry actually are in the farmland niche, I saw the value in what AcreTrader had to offer, simply because they allow people to get in with less money and risk, and they do all the research and due diligence for you. Obviously, any crowdfunding platform is only as good as the people administrating it, but if you've really got the itch to get into that side of real estate, it could be a less-committal way to see more of how it works. You can a bit more of how it works in this interview I did with them...
Al
...or alternatively, you can wait until the next time farmland values take a dip.