Introduced from where? That’s my whole question. Apparently you don’t know but phosphorus is a finite resource which will run out in the next 100-300 years. It’s just as fossil as fossil fuel. Any solution that uses mined phosphorus is not sustainable.

I missed that azolla could fix nitrogen, knew that about duckweed but azolla is not my strength to be honest. However the question still remains, where would you get the potassium and phosphorus required to grow the azolla? All 3 of your examples involve continually harvesting azolla and not getting the nutrients back in. You could add chemical fertilizer to grow azolla into organic fertilizer but that would be kinda dumb wouldn’t it? Not to say that hasn’t been done multiple times before, looking at you alfalfa fertilizer pellets.

In a way wood is a great way to produce biochar because nearly all the nutrients in the tree are in the leaves and the branches. When harvesting wood we only take the trunk. This means we can grow wood generation after generation and we don’t have to use fertilizer. The same is not true for something like azolla. A good setup to make it cyclical would be to put the azolla right next to the animal farm whose animals are fed the azolla. And use the manure to grow azolla. However then I wonder if the hygienic quality is acceptable.

You can feed the azolla waste water from a fish farm for sure. But then what do you feed the fish? The nutrients always have to come from somewhere and they have to end up somewhere. If you’re simply dumping azolla in a mine somewhere as carbon storage that then turns into a huge waste of nitrogen, phosphorus and potassium. It’s a very nutrient dense plant.

What would you use the azolla for? Animal feed? Which source of nutrients would you feed it with? Intensive harvesting of azolla would quickly deplete the nutrients in the water.

You are right about the risk of heavy metal contamination so wont comment on that. But if we are speaking about an animal that crapped on top of the clay pile then that should not be an issue. Soil in general but especially clay has an absolutely enormous surface area that adsorbs both bacteria and viruses. That’s why ground water is usually safe to drink but surface water is not. A large amount of faeces leaking into the soil water from above would potentially contaminate the water with nitrate which could be a slight cancer risk if consumed in large quantities but there should be no risk of getting infected if you are digging deep unexposed clay, even if an animal crapped on top of the pile. As long as there is no heavy metal contamination eating deep clay is probably safer than eating a wild picked berry.

All the ones you listed are either:

Not native to soil but may be on soil if faeces got on there Or Not dangerous in soil but will become dangerous if food gets into contact with it before fermenting Or Only dangerous getting into your blood, but not your mouth.

As long as there is no literal poop on the soil you can eat it raw. These people mentioned in the article were digging deep clay which would carry absolutely no risk of faeces contamination.

After cooking with high heat there should be no germs left. As stated in the article there are no health risks involved except if you eat such a large amount it blocks your intestines. Also even if you didn’t cook it the germs that live in soil are not the same germs that make you sick, those you get from your fellow humans.

I don’t know the reasoning of that fox news analyst. But it is true that the declining birth rates are to a large extent due to less teens and early 20s women having kids. The amount of late 30s and 40s women having kids has actually increased in the same period. Kinda ironic how the young single moms conservative media have been shaming and demonizing for decades were actually the ones keeping the birth rate up. And now that they are far fewer suddenly that’s a problem as well.