In the comments thread on a recent post, the subject of "permaculture" came up. I have a couple of permaculture books listed in the right margin, and the commenter was interested in the relative merits of each. As I told him, the "Designers Manual" is much more detailed than the average person needs; the "Introduction to Permaculture" is a good practical overview of key principles. I noted that the prices for both books on Amazon are really high. In the days since, Mrs Yeoman Farmer pointed out to me that the "Seeds of Change" site has the Designers Manual for much less than Amazon is currently listing it for --- and they also have a number of other relatively affordable permaculture books. I can't personally vouch for those, but they look good.
Our one big criticism of Bill Mollison's books is that he is Australian --- and his diagrams therefore assume that northern exposures give the most sunlight for plants (exactly the opposite of the case in North America). He addresses this issue in the text, but many of the diagrams still seem oddly "upside down" and we sometimes struggle to understand them. It's like trying to work on an American car using a Haynes Manual from England; all the information is there, but you have to keep remembering to turn it around.
Some other good permaculture sites include the Permaculture Institute and the International Institute for Ecological Agriculture. The latter is home to "Farmer Dave" Blume; he's a fascinating and extremely knowledgeable character, and we had the opportunity to attend one of his full-day permaculture workshops in Illinois a few years ago.
One way to think of permaculture is as "permanent agriculture." Or, as the Wikipedia definition puts it: "an approach to designing human settlements and perennial agricultural systems that mimic the relationships found in the natural ecologies."
We have chosen to incorporate some aspects of this approach in our own farm, but we have never been able to set up our entire property following permaculture guidelines. In practical terms, for us, permaculture has meant:
1) Cultivating as many perennial fruiting trees, brambles, and vines as possible. These not only provide fruit for the humans, but lots of "windfalls" and extras that can feed livestock. In the fall, when apples and pears are coming down like crazy, we toss the extras over the pasture fence --- and watch the sheep come running at full speed. A few mature mulberry trees out in the chicken yard will provide lots and lots of supplementary feed (not to mention entertainment, as the hens scramble to grab ripe berries every time the wind picks up and rustles the branches). But, as MYF cautions, keep the mulberry trees far from your garden --- they will spread and become a real nuisance.
2) Integrating livestock with plants as a system. Our movable poultry pens, serving as tractors, are a prime example. Pens of waterfowl are perfect for clearing new garden beds in the sod. Then make your garden twice as large as you need, and run chickens or turkeys in pens on the unused beds. The birds mow the weeds, get green stuff and bug protein in their diet, reduce the bug population in the garden, and leave fertilizer behind. The next year, those beds get planted --- and the poultry pens can move on the beds that had been previously cultivated. We also ran pens up and down the aisles of our vineyard in Illinois; in addition to providing fertilizer and weed control, they also did a number on the Japanese beetles. Next year, we will be introducing bees to our farm; they will provide an important service as pollinators, and will also provide honey.
3) Utilizing large PVC tanks to catch rainwater, and then releasing that water for livestock or the vineyard.
A very important theme of permaculture is that, whenever possible, the outputs from one component of the farm should serve as inputs for another component. Mollison's book is outstanding in giving ideas for constructing these sorts of systems. (Just remember that North means South and South means North!)
Bottom line: The key to permaculture is to work with your property, taking advantage of its natural characteristics, and fostering connections within it, rather than declaring war on it.