Oh boy! If you have heavy clay soil--welcome to the club! I've been ammending mine with lots of organic material: I started this spring with about 1" each of manure and peat moss tilled in the top 10-12". Then this fall I added another 1" of compost and 2" of grass clippings and tilled in again. I do not plan on adding more material than this. I'm going to try "tilless" gardening and topdress with compost and mulch only from now on. That should make gardening much more enjoyable and a lot less work for me!
Of course, I am only gardening in 200 sq ft or so, so I still have less work than you do! I hear that a nitrogen-fixing green manure (like beans of some sort) will encourage bacteria to reinhabit the soil.
Good luck with your learning process! There are a lot of great people on here that answer questions all the time!