Grandfathers didn't know any more than than anyone else. Most of them farmed all the soil health away and didn't realize what they were doing. The native soils were turned over with a plow, had plenty of nutrients for good crops for years and years. The Turkey Red wheat they brought from Europe, raises 30 bu crops for years without anything added, until they wore the soil out, reducing the original humous content from about 8% to below 2% in many cases.
I went no-til in 1996, tried the cover crop approach some years later. I attended enough seminars to convince me it was a method that we needed to adopt. But, that old saying, " Farming looks mighty easy when your plow is a pencil and you're a thousand miles from the corn field. " is and always has been valid. Try it in real life, it doesn't follow the rules ya learned in class. And that speaker's comments on growing good crops on only 2" is the biggest line of shit I've ever heard. Almost every no-tiller in the area here planted a crop right behind the wheat combine here in June. It is so hot and dry, nothing emerged. NOTHING. Even on land that has been no-tilled for 30 years. The cotton planted on open ground, not following wheat, is the only thing that is green at present, it's flowering now - - - - - - - mostly at 6" tall. It's so damn dry and hot, even the tough cotton plant as struggling.
This guy reminds me of investment counselors, they have all the answers of how to make you rich, but they are not rich themsleves, they are work-a-day people, selling a product to gullible people. If what this guy says is true, and was that easy, everyone would be doing it and quitting what they are doing. Farmers aren't stupid, they will transition if something proves to be successful. What this speaker isn't saying is the labor involved in maintaining what he is doing. Many farmers are single man operations, many with their sons along with them. It hard to find farm labor these days, no one wants to work. Less than 2% of this country are farmers, not many want to put in the work anymore, and it's dwindling every year. If this method works so well, people would be flocking to it. That was the big shift in agrarian lifestyles at the turn of the century. When a small fraction of citizenry decided to raise food for the other 95% + of the country, the 95% let them. The 95% got lazy, and that trait won't change.
The speaker's potato crop was impressive, I've grown potatoes in hay bales too, it's not rocket science. But, he used some land somewhere to produce the compost he applied, and more intensive labor to produce it. And all that seed he plants for cover crops is produced by someone else, I'll lay odds. And it ain't cheap, BTDT.
Once again, if it was so damn easy, and so successful, the world would be flocking to it. He runs a very intensive livestock operation on his land, plus the pigs and chickens. What are they gonna do in the near future when we decouple from the use of consuming animals, if the greenies have their way. Oops. I'm just glad I'm retired and all I have to worry about is myself for a while.