Anyone have new ideas for an old, intractable problem?
It's okay if you don't. I don't really think there is a workable answer at this point, but I thought I'd throw it out there, since spring is springing.
The background:
I have 6 acres of dirt, rocks, and weeds. There are others, but the worst of the weeds are cheat grass, mustard weed, and the horrific perennial pepper weed, which spreads on runners underground and crops up wherever anything is watered. Like my little orchard.
When I say rocks, I mean ROCK. This is a volcanic area. I have more rock than soil. They sprout out of the ground everywhere through a very thin layer of soil; new rocks seem to "grow" out of the ground every year. Even with a small back hoe or an auger, I can't get more than about 18 inches down without hitting rock too solid to break through.
That means that weed control is a disaster. I can't hand weed 6 acres. Mowers break on the rocks. I can't afford bigger equipment, to buy or rent. At this point, with a pay cut every year for the last 5, I'm barely able to make the mortgage. Weedeaters...again, 6 acres. Both of mine are currently broken, with no funds to replace or repair. Besides, weedeating in the rocks is hazardous and painful.
I have some supposedly organic stuff: "Burn Out." Industrial strength vinegar concoction. I've never used it, because it requires a certain temperature, and by the time it gets that warm here the weeds are already waist high. I have refused to use Monsanto products and other non-organic herbicides; I have animals.
I've tried sheep. They ignore the weeds and eat the bushes and trees.
The place is greening up. Right now, everything is about 1/4 of an inch tall. All 6 acres worth.
Suggestions that don't involve $$$ I don't have for tractors, etc.?
One year a local suggested burning; he came out, tried to burn off the weeds in a pasture, and set the local blm on fire on the other side of my fence. And left me to stay up all night with 200 ft long hoses, trying to put the fire out before the fire department found out and charged me. It was burning underground around the deep litter underneath a few trees.
= new reply since forum marked as read
My fruit trees are dwarves; she ignores the pepper weed and strips the trees, so I don't let her in anymore. She likes roses, lilacs, and various other deliberately planted things, as well. She will eat a little cheat, but not much. She ignores the mustard and pepperweed. 
yes, they eat weeds! They have incredibly strong snout muscles and will root up many smaller rocks and will loosen the soil around larger ones... I used to use pigs specifically to clear land.... must have good elecric fence though, to keep them in... but they are real sweethearts 
I used to sleep with my sows during farrowing time, so I could protect the tiny babies from their big floppy mums
