
No electric fencing??? That's too bad. You said your dirt doesn't allow for buried wire. Does that mean it's hard? If that's the deal then you don't have much to fear with digging. You can apron some wire on top too, no need to dig.
I once had raccoons decide to start a latrine in my vegetable garden. I got them to stop by using chili pepper. I got a big container of crushed red pepper at Costco, the kind you put on pizza. I sprinkled it around the area where they were getting in and they stopped. It doesn't affect birds at all but mammals don't like it. I know nothing about quail, but I wouldn't know why they would be different in that respect.
How habituated to humans are your coyotes? You could also take some clothes you've worn and stuff them with straw or leaves, make a sort of scare crow thing, put it in a lawn chair out by your tractor. Might work for a while, but you'd need to move it around often I would think.
Sorry I keep cluttering up your thread, I've been dodging pests from deer to raccoons to coyotes and hawks and it's a subject I'm always thinking about. Good luck and let us know what you come up with!
Cathy