Can't stress enough that you'll be adding amendments to your clay for years upon years and it will just eat them up like they never were. I've done cover crops, green manure, mulch, char, age manure, hay, minimal tilling, etc. for the past 20+ years here and the clay is just has hard as a rock after a rain settles it after tilling or turning, even if heavily mulched afterward. But...there is light at the end of the tunnel...finally...
The Back to Eden method turned on a light and I'm happy to see that it's working....I'll never have to till or turn in amendments again. The key to clay soil, I'm finding, is not to turn things into it, but to build on top of it and let the worms turn the compost into it. I've had wood chips on my clay since last May and I'm just in awe, after all these years, to see actual changes in the soil and a new layer of dark, rich top soil starting on top of the clay.
That's happening in my orchard also, with dark green grass growing around the edges of the wood chips and leaves I've deposited under the trees....before, we could never grow grass, just moss. Now the orchard is full of clover and grass where before none existed...and that's just from the nutrient runoff around these piles of chips and leaves.
Around the garden the grass is much more dark and lush, as it's receiving the nutrient flush from the composting chips as well. The 6 in. layer of wood chips and leaves keeps the soil underneath loose and moist, I have a full megaton of worms now that I've never seen in this soil...huge, fat and many of them...and the thick cover on the soil suppresses weed growth.
I didn't have to wait until the clay soil was dry enough to till in this year, so I got early crops out early as they are supposed to be done. I've even got spuds up already, having planted them~not in the clay, but on top of it~in the late fall, then covered them over with chips, leaves, grass clippings, chips, leaves, etc.
This method was the answer to all my problems with the clay soil, the hard work each year to get that soil loose enough to plant into, then keeping it loose enough for root growth and moisture absorption, etc. Now it's as easy as pulling back the chips and planting on top of the now crumbly clay, raking a light layer of the fine, black particles of the compost over the seed, waiting for it to emerge and get tall enough to put the chips back around it to keep the moisture in and continue composting around the seedling. Each year that will get easier and easier as the topsoil deepens and the chip layer thins. Eventually I'll add more chips to keep my soil covering but that topsoil layer will be only getting thicker and thicker, just lying there on top of the nasty ol' clay.