Tuesday, April 8, 2008
Stuck in the brown stuff, or, Can you garden well without animal manures in a northern climate?
This came up the other day. It's a sub-set of the question "Why would we want a farm at Unity College." As is the sheep post below.
Lots of Unity students are vegetarian because they worry about the way animals are treated in the factory farm system. And if you ever went to a CAFO or similar, you'd be disgusted too, and would begin to worry. Unless you were a completely thoughtless individual. I hate to see animals confined in crowded, squalid quarters.
But the most stable human ecological adaptive strategy since hunting and gathering is the mixed farm system, in which manures and rotations are used to maintain fertility. There are hundreds of regional versions, but the one I practice at home with my wife Aimee (who is vegetarian) uses winter shelter (a barn) to concentrate manures and bedding for processing (composting) and delivery to the garden. Animals need winter shelter in Maine anyway, especially for raising young. This is very effective, and we even get two different kinds, sheep manure and chicken manure, which have different nitrogen levels and are good for different uses, (although so far we haven't gotten to the point of separating them into different compost heaps, but I'm going to be working a lot with compost this summer.
It's possible to use vegetable material alone to build compost, but you must bring some new material into the cycle. You can't just add the waste material from your garden to a pile and expect to maintain fertility (another application of the Laws of Thermodynamics). If you import a lot of outside food to your kitchen, and waste a lot to your compost heap, and cycle your own manure (your poop!) into the garden, you might just make out on the basis of the outside food. But otherwise, even using your own waste as manure, you will see a steady decline in your system fertility, and have to import some material from some other source, likely industrial, with associated climate emissions. Most nitrogenous industrial fertilizer is made using natural gas as the primary input to provide energy to take nitrogen from the air. You can also do this with a cover crop or green manure, which too will import nitrogen from the atmosphere. But animals provide real manure, the fertility of which is imported from self-maintaining mixed pastures and forage crops. To be successful, the pastures and hayfields have to have nitrogen-fixing plants too.
I remember the Amish fields in western Maryland. The native soil was reddish-brown, but the Amish farmer's fields were coal-black from years of manuring.
This is the best argument for mixed farming systems in Maine and in fact anywhere where cold weather is a factor (and thus concentrated manure from winter housing). In my home country of Great Britain, this system has been sustainable and sustained for 2-3,000 years at least. Here in Maine, it has lasted so far for 210-250 years (at the most). In practice, you don't need to mix systems on the same farm. I know lots of people who farm or garden organically, but get their manure and other inputs from off the farm.
My wife, the vegetarian, imposes one condition on our system. I must be the one to slaughter the animals, and I must do it at home. No transportation of terrified creatures allowed.
Generally, by the time the time comes around for the pigs, fat lambs, or whatever, she is ready for me to do the deed.