One of the things on my list to research is biochar. I'm far from being finished researching, but I was so excited about this one video I found that I couldn't wait to share it. This link will give you some general information about biochar, AKA Terra Preta which was evidently made by prehistoric peoples in the Amazon basin. Biochar has some remarkable properties, not the least of which is that the soil fertility it produces lasts for centuries, if not millennia.
I am always interested in the do-it-yourself version of something, so I also looked for making biochar, which brings me to the video that I couldn't wait to show you. Take a look at Making Biochar
and I'll tell you ahead of time: I was really impressed with what happened to the smoke when he put the stack on. He also gives a lot of good information about biochar as well. After watching this though, I realized that the charcoal that I'm pulling out of my woodstove with the wood ashes is basically made the same way, because our stove burns off the wood gases. I'll have to sift them out of the ashes first though, because the ashes can be applied directly to the soil, but the charcoal cannot or it will compete with the plants for nutrients. You have to innoculate the charcoal first by mixing it into your compost (and some fish emulsion wouldn't hurt either) to get the good microbes to take up residence in the charcoal, and then you can add it to the soil. It's supposed to be immediately bioavailable to the plants at that point as well.
But don't take it from me- do some research of your own on biochar- it's kind of a fascinating dig.