Wood ash is full of minerals, lots of P and K but no N, it has zero nitrate. So if azolla grows in water above wood ash, it has to fix nitrogen from the air, there is nowhere else it can get it! The Iran war has stopped 30% of the world's nitrate production so we have to fall back on the natural world to fill the gap and it simply cannot. I read somewhere that Azolla can fix nitrogen twice as fast as any other higher plant, so it has that going for it! On 28 April, i put 50 grams of wood ash into an aquarium (surface area 1127 sq centimeter, along with 25.9 liters of water and 30 grams of azolla. I also conducted the experiment in a larger aquarium. In that one I added 100g wood ash, 51 liters of water and 111g of azolla, its surface area was 2250 sq cm. The big aquarium was in a more sheltered area. I didn't even know if the azolla could grow with that much wood ash, (it makes the water pretty alkaline). There were a few things swimming when I added the water but by 2 days after, I didn't see any animal life in either aquarium. Probably killed by the alkalinity or maybe toxic stuff in the ash. About 2 weeks later I weighed the azolla. In the little aquarium it had more than doubled in weight (2.93 times on may 14th), but was still not covering the surface. In the big one it covered the surface but had only increased from 111 to 254 grams, 2.28 times the amount I started with. So I harvested some and filled both aquariums with Azolla again, (almost covering the surface in both of them.) Anyway, next stage is to harvest some every week (1/7 of the surface area, I guess) and get it to a steady state of growth. I plan to expand the experiment to several shallow containers too. Small scale farmers across Africa and Asia grow azolla, but their ponds are often fertilized with chicken manure, or pig or cow manure, which contain nitrates so this means their azolla is probably not fixing so much nitrogen, because the plant gets it from the water if it can. (it takes less energy to suck it up than to make it!) Anyway, my experiment shows that Azolla can survive with that much ash in the water. Maybe in the future other people will grow azolla in Ash ponds? I think it is a good way of converting the ash into a full spectrum fertilizer! And if you don't want to spread the azolla as a mulch, you can always feed it to your animals or fish as part of a varied diet. I think I will harvest some azolla, solar cook it, and then mix it up with pure sand in a pot, then grow some plants (not legumes) in the mixture. I will probably mulch it with azolla too too. So whatever grows in the pot, its only source of nitrogen is the decomposing azolla in the pot. Here is a brief video about the Azolla experiment. Please don't be shy and leave a comment. The haters are usually not shy, and they freak out at new (to them) ideas, so help balance them out.
Thanks Brian
