Didn't know where to post this, cover crop seemed the closest. Apparently in old growth forests nearer the arctic there are mosses that hang in the trees that fix nitrogen (or maybe they host microbes that do the actual fixing--sort of like when I try to fix dinner for my mom). I just heard about this from a permie in Alabama, and what I googled may or may not be what he was talking about but it's discussing "n-fixing mosses". I don't know if these are the ones that hang in the older trees.
I'll google some more, but I thought this was amazing and wanted to share right away!
Community Building 2.0: ask me about drL, the rotational-mob-grazing format for human interactions.
How would this be put to use, do you imagine? Are there rock-surface-growing nitrogen-fixing mosses, or do they exclusively hang in trees; is it only one species or group?
I found this study in a brief search. Their findings are all in the precis at the beginning. They are studying it from the perspective of mosses as methanotrophs (they derive their nutrition primarily from atmospheric methane), but their findings related to nitrogen fixation are relevant.
They found that nitrogen fixation decreases in the presence of added nitrogen, presumably from nitrogen pollution in the rain. They also found a higher rate of nitrogen fixation in mosses with a higher carbon to nitrogen ratio, and that the green parts fixed more than the brown.
They also found greater nitrogen fixation rates in locations of lower nitrogen deposition, to the north. They found, by the way, that overall, methanotrophy in forest mosses remains low.
Here are the highlights:
► N2 fixation in forest mosses was studied using acetylene reduction and 15N2 methods. ► The methods gave corresponding results with the conversion factor of 3.3. ► Moss-associated N2 fixation was higher in the northern samples with low N deposition. ► Methanotrophic activity associated with forest mosses was low.
Fascinating, in any case. I hadn't even thought about that part of it, although I had been thinking about how natural mineral stuccos could be used in conjunction with mineral-appropriate moss and lichen species as retrofitted outer building envelopes in appropriate environments.
After reading an article about an air filtration system set up in China, I think it was, that looked like a stone monolith growing moss, that apparently cleaned the air of particulates and carbon dioxide as well as a small forest of trees could, I was thinking that if you could do that, but with the outer building envelopes of whole buildings, and sell it as an environmental retrofit that decreases solar gain, UV damage to the building shell, water damage, and lends an interesting, organic aesthetic, we would end up cleaning a lot of air and sequestering a lot of carbon.
As to the tree-hanging nitrogen, though, what would you envision? Would the moss need to be harvested to be used as a nitrogen-rich mulch, or would there be some engineered symbiosis? Would we perhaps encourage growth of this stuff, in an arboriculture, perhaps, and harvest the die-off, or some living parts?
I assume you're aware of this thread about the discovery of nitrogen-fixing corn? That was a mindf%ck for me.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein