Just wanted to say thanks for linking to our blog (http://sustainable-farming.blogspot.com) here. This is really cool!

Of course, Mother Earth News has been a source of inspiration and knowledge for me for the past many years. Thanks to the team for running a great publication!

If you have neighbors or a an implement dealer that can rent you a tractor when you need it, perhaps one or two times a year, then draft horses or mules could be a good fit for many small farms. My Amish neghbors use standard bred horses for pulling buggies because they are faster than draft horses or mules. They use thier draft horses to pull wagons, spread manure, plow, disc, drill seed, cut hay, rake hay and bale hay.
When they want to brush hog an area due too heavy weeds or reclaming an overgrown farm that they just bought they call me and my tractor. They also use its front loader and post hole digger. There are somethings the horse and horse drawn implements just will not do. Modern hydrolic implements are really amazing thus exspensive.
For me it was- Do I know how to operate and maintain a tractor? Can I maintain a tractor (change oil, air filters, tires, grease it)? Can I take care of a horse (feed, trim feet/shoe it, worm, give it vaccinations)? Do I know how to farm with horses?
The bottom line I did not know how to drive a team ,hook up a wagon or farm implement. I have since learned and would proably switch to a team of horses if my neighbors had not asked me not to. I was thinking of selling my tractor and purchasing an older team of mares. I figured if I did not work them hard that they would last another 8 to 10 years and give me at least 8 colts during that time.
Of course I would be the one renting when I needed a front end loader, post hole digger or brush hog. Clearing snow from a drive way to be able to get cars in and out is one very important function of my tractor.
I have not yet had to use it to generate electrical power. I have a PTO generator that I am very happy not to have to use. The folks in the St Josph were without power for weeks two years ago, Springfield last winter and most of southeastern Missouri this winter.
The tractor verses horses question is more complicated than what it first appears.