I think there are two types that dump on their own ground.
The first is one of the prior owners of my 40 acres. He just took a bulldozer and pushed stuff around until it was buried. The problem was he didn't bury a lot of it below the frost line so more comes to the surface each year. So far, I've found an old log chain, old fan belts, a couple of old tires, an old alternator, miscellaneous equipment brackets, beer cans, bottles, barbed wire, a couple of T-posts, an 6 inch metal pipe, a bunch of old plastic pipe, a pallet, old vehicle lights, an old box spring (just the springs, the material is long gone), some old broken tile and a metal 3x3x3 box open on one side. Most of it I've been able to pick up and take home to the trash bin. Some of it is only part exposed and won't pull out. (That box spring is a pain. Mostly buried and in a location I can't back the tractor to and drag out. I know where he moved and his current place isn't much better. He's just a slob who doesn't care what he dumps anywhere.
The other type is like the guy who has the 11 acres to my west. To most people it looks like a bad junk yard. From talking to him, it is obvious he grew up dirt poor and in an abusive household. He worked for the gas company and would come across stuff people would give him if he just took it away. Some of it is pure junk. The worst is an old mobile home that is collapsing. One side of it is completely down and the roof is mostly caved in. Some of it is pretty interesting. He has some old cars that would be really cool in the right hands, several 1930's Chevy's, an old Suburban, he had an old Karman Ghia but that left recently. I'm told he has some really nice stuff stored in the metal barn he had built. There is an old tractor that would be cool if it was restored. Some of the cars are just junk, a 1977 Camaro, an old Pinto, etc. He has some old light poles from the early 1900's. Those are pretty cool and could be a very neat item in the right setting. Basically, this stuff is all treasure to him. He is very protective of it. But he has screwed up the title to the ground. He titled it in the name of a corporation that has never existed in this state. He will own that ground till he dies. The attorney's fee to fix that title will be quite expensive I expect and probably take several years, may even lead to fight if somebody tries to say it is a corporation from another state. But this is him trying to cling things he could never have as a child. Lucky for me it is mostly out of sight.