Anyways their is a couple ways one can incorporate organic matter into your garden soil. You can either spread a bunch on top and mechanically mix it in using a cultivator. Or you can used the traditional and newly rediscovered method of using cover crops to add O.M. both above and below ground. Cover crops can either be planted as part of a rotation and done once every couple of years or you can squeeze them in between the main garden crops. This will usually mean a spring planted cover crop that is killed and incorporated into the soil prior to the main veggies going in. Or what I consider to be the easier method of the fall cover crop and let it go till the frost kills it.
Some of you may live where frost is not a concern and would worry about the cover crop becoming a weed. If that is the case you may have to try to kill it mechanically or chemically(not a fan).
So to circle back around to my main point I have planted a cover crop of Peas and Oats. The combination of peas and oats is a strong one as it suppresses weeds, fixes nitrogen from the atmosphere, and shoots roots deep into the soil loosing up the clay and adding organic matter all through the soil profile of my garden.
The goal with the cover crop is to have a loose, weed free garden bed ready for planting next spring.