If you've begun salivating, you better just hold up there! Though it sounds delicious, this is actually a method of gardening I'm talking about. I've read about it sometime during my teenage years, and have just now recently rediscovered it. The other week I had gone to pick up a bale of straw and a heap o' half-decomposed horse manure from a kind neighbor offering it for free on craigslist. I was planning to just add it to my compost pile but I noticed this neighbors garden was covered with straw and manure. I asked him about it and he told me about the lasagna method of gardening. He covered his beds with three layers; cardboard first, then straw, then topped it off with the horse manure.
The purpose of the cardboard is to prevent any weeds from poking through, as well as create a dark, damp place for worms to wiggle around in the topsoil. This will help break up any clay-like soil while adding organic matter(worm poo!). A few layers of newspaper can substitute for cardboard as well.
I admit I did not use any cardboard. I kept my garden pretty weed free so I chose to leave that layer out. I covered my beds with a good layer of straw and topped it off with the manure. I plan to leave this to decompose over the winter and dig it under in the spring. One of the main attractions of lasagna gardening is that if one has a lawn and some patience, he could turn a grass-covered plot into new garden beds over a winter without having to dig up any sod! With the initial cardboard layer and the subsequent top layers light will not be able to pass through, snuffing out any plants below. And the new layer of organic materials will provide ample nutrients for the garden-to-be!
Now what I've done is a very simple method. Obviously two layers isn't much of a lasagna! But the general idea is still there and come spring I should have enhanced soil. I will of course report on my experience with this, checking in to see how much decomposition has taken place, and taking note on whether I see a difference in my plants next season.