FORT WORTH — Gabe Brown is in such demand as a speaker that for every invitation he accepts, he turns down 10 more. At conferences, like the one held here at a Best Western hotel recently, people line up to seek his advice.

“The greatest roadblock to solving a problem is the human mind,” he tells audiences.

Mr. Brown, a balding North Dakota farmer who favors baseball caps and red-striped polo shirts, is not talking about disruptive technology start-ups, political causes, or the latest self-help fad.

He is talking about farming, specifically soil-conservation farming, a movement that promotes leaving fields untilled, “green manures” and other soil-enhancing methods with an almost evangelistic fervor.

Such farming methods, which mimic the biology of virgin land, can revive degenerated earth, minimize erosion, encourage plant growth and increase farmers’ profits, their proponents say. And by using them, Mr. Brown told more than 250 farmers and ranchers who gathered at the hotel for the first Southern Soil Health Conference, he has produced crops that thrive on his 5,000-acre farm outside of Bismarck, N.D., even during droughts or flooding.