Hi Permies forums,

This is my first post and I have some questions that have been on my mind for several months. I recently asked the basic form of the question to a permaculture teacher in my area and he wasn't even aware that the N-fixing tree isn't actually what does the act of fixing nitrogen. I've read that specific N-fixing trees need specific mycorrhizal fungi to associate with and if those fungi aren't there then the tree won't have any nitrogen fixation capability, will grow at have it's normal rate, and sometimes won't survive My basic question are: how specific are the different types of nitrogen fixing bacteria to their hosts? As an example, let's say I were to plant a honey mesquite tree in an area of Arizona dominated by velvet mesquite tree. Would the honey mesquite be able to form an association with the existing mycorrhizal fungi or for maximum nitrogen fixation and growth, would I need a starter from place where that specific variety grows or a specific inoculant. As another example if I wanted to plant an edible acacia tree from Australia in Arizona would I need a starter of the mycorrhizal fungi from that place. Does anyone have any sources for starters for different legume trees. As my current understanding goes, myrcorrhizal diversity is very good for soil, so I'd like to have as much diversity as possible in my N-fixing trees and their mycorrhizal associates. Any advice on this topic would be greatly appreciated by me. Thank so much!

They need to have a kind of bacteria that works with nodules on the roots to make nitrogen available from the air.

Mycorrhizal fungi are amazing, but they're different than that.
John S
PDX OR

Thank you for pointing out that distinction. It shows how much research I still have to do to gain a thorough understanding of this topic. I still do, however, have the same basic question even if the words "mycorrhizal fungi" have to be swapped for "N-fixing bacteria" in my original post.