Just got my copy of Organic Gardening in the mail--the one with the beets on the cover--and there's an interesting article about carbon. When I think of soil, I'm always thinking about what to add to it--manure, bone meal, microbes, alfalfa pellets, worm castings--it's all about what cool thing I can put in my soil to perk it up.
But the article's author, Erika Jensen, takes a step back and points out that plants live on carbon (and so do we, as carbon-based life forms.) They breathe it in as a gas, they convert it to leaves and branches and bark, and when they die, critters break them down and convert them back into carbon, which other plants can breathe. That's the carbon cycle.
When you add organic matter--manure, compost, shredded leaves, grass clippings--to your soil, what you're really doing is putting carbon back into the earth. She even points out that if the earth stores more carbon, that keeps it out of the atmosphere, where it can contribute (in a small way) to global warming.
Got me thinking. Check it out.
P.S. Oh yeah, I have an article about organic grapes in that issue. Check that out, too.