- Long-term stability. If something happens to change your urine-recycling contributions to the forest garden, nitrogen fixers will still keep the nitrogen flowing if you've designed them well. Crack-down by the neighborhood association on renegade pee-ers-in-the-night, exodus of your housemates on whom you depended for their piss, or selling your property to mainstream squeamish folks could all leave your forest garden without the nitrogen inputs it needs for optimal performance.
- Ongoing slow release of non-messy fertilizer. For patches where you're growing salad greens you want to harvest frequently, n-fixers provide a much cleaner nitrogen source than splashing your piss around.
- Frees up your nitrogen for application elsewhere. Knowing that you have ample nitrogen available at home, you can gleefully fertilize wild patches of vegetation, injecting helpful nutrients to partially compensate for the abuses they suffer from civilization. I find it a lot easier to go pee in the woods and grow a Goumi at home than to plant and tend a goumi in the woods and pee at home.
- Other uses. Many nitrogen fixers have other uses which warrant their inclusion in your food forest regardless of their nitrogen contributions. Off the top of my head, I can think of nitrogen-fixers which also provide or act as ground covers, fast growing cover crops, tea, human food, wildlife food, chicken forage, bee nectaries, foot-tolerant steppables, and dynamic accumulation of phosphorous and other nutrients.
- Learning about particular plants through direct experience now. When we move to a rural area and start growing quarter acre food forests per person, we won't be able to fertilize the whole area from which our food comes. I feel glad that we're currently growing Elaeagnus, pea shrubs, black locusts, and various herbaceous nitrogen fixers which I expect to use in our larger systems in the future. If you ever design or give input for project for squeamish neighbors or friends, or for public demonstration gardens where the public "ick" factor precludes urinal input, then having experience with n-fixers will allow you to do a better job of integrating them into a system which actually needs them.
Wednesday, December 12, 2007
Why we love the N-fixers anyway
So in most urban lot forest gardens, you probably don't need nitrogen-fixing plants for their nitrogren input if you're recycling your urine. I'll throw out some reasons to keep them around anyway: