I plan to use a 12" dia auger to drill holes into the red clay, and put a chunk of wood on the bottom of the hole and let the composted wood chips mix in the hole also with the loosened clay. It takes a LOT of the organic material to break up the clay bonds I think. Huegelkulture = 'termite tek' I think.My efforts to loosen up clay with compost have been dire. It seems that to fix up 1Kg of clay, needs perhaps 1Kg of compost. However, clay must have 3 times the SG and I would like to see the top 6" come good. So, maybe, I need 18" of compost. Which is unrealistic to walk a mile with.
I have filled 10L holes with 50/50 mix, and a couple of seasons later the clay has taken in. Somehow liquefied over the winters. Run through the compost, and dropped in the hole a long way. Which is where the 3:1 ratio idea is coming from. Years on, having turned these holes again, adding more compost, I really need to reevaluate that ratio again. As it's really not happening. Though the ground is changing colour, it is still clay.