Eric Hanson wrote:Todd,
So from what you are saying, it sounds like it really comes down to N after all. This is the reason I am trying my comfrey cover crop idea in the first place. I am hoping to charge up the soil with nitrogen for eventual release. Perhaps the comfrey will crowd out the clover, but by that point, the clover will have done its job and by dying it should give up a last batch of N for the comfrey to feed upon. You say use urine. I am totally OK with this and I have already give my comfrey plants a good helping of diluted urine and plan to continue. This plus the clover in addition to any soil-borne nitrogen already in place will hopefully provide plenty of nitrogen for comfrey plants.
Comfrey doesn't make a good "cover crop" for larger areas, but does for under trees and along paths. Your better off with a fast growing annual, such as Kodiak spinach, to start with, then progressively expand your other perennials. Just chop the spinach before it goes to seed and you'll have a great mulch starter.
With regards to the nitrogen issue, but a cheap bag of beans or peas and scatter them about, let them grow, then chop and drop them. Your Comfrey isn't a nitrogen fixer, but it doesn't strip it out like a lot of other plants. Most of it's resources are pulled from well below the depth of other plants. So, once the Comfrey takes hold and gets it's roots down deep, you'll find that chopping and dropping it will help with nitrogen depletion.
Another nitrogen fix is to run wood chips through a 1/4" screen, mix that 2 to 1 with aged manure and spread a few inches around your plants for a fast breakdown and release of nitrogen. Then just take the remaining wood chips and spread in thick layers to keep the process going.
You can also add a little chicken manure for a quick nitrogen fix.
Within a few months you'll have a few inches of beautiful, healthy, active soil.
Hope this helps.