Plants need at least 42 minerals and soil in every location of the planet has those minerals, mostly in insoluable (non plant available) form. Aerobic bacteries and funghi have enzymes that extract those minerals and they are mostly kept in their bodies.
Amoebas and worms of all sizes eat bacteries and funghi which releases a large amount of minerals in water soluable form in their poop and coincidently the poop is nearby the roots of plants.
Some plants are called "nitrogen fixers" since they have clumbs of bacteries on their roots that convert N2 into plant available forms of nitrogen. Plowed soil is fluffy after plowing and compacted after a few weeks since the plowed soil has no structure.
What can we learn from these facts?
* do everything possible to keep the life in the soil alive: do not use pesticides, funghicides or herbicides since the toxins are not specific and kill all soil life.
* aerate the soil to have enough oxygen (O2) and nitrate (N2) in the soil. Use a broadfork, but only with compacted soil.
* do not plow since that breaks the networks of funghi and ultimately deteriorates the performance of plants.
> do everything possible to keep the life in the soil alive: do not use pesticides, funghicides or herbicides since the toxins are not specific and kill all soil life.
It should be noted that glyphosate has antimicrobial and fungicidal properties.
Also, plants can turn the bedrock into dirt, either directly, or through their mycorrhyzal and rhyzosphere bacteria. Trees are especially useful to extract nutrient from rocks.
That being said, I think that Merril has a point. we're accelerating the extraction process (by dumping our waste products in rivers, rather than peeing/pooping where plants grow), and I have no idea how long we'll get away with these practices.
Human effluvia is full of drugs, and thus unfit for agriculture anyways...
> Human effluvia is full of drugs, and thus unfit for agriculture anyways...
For direct application, yes. But it could feed a pipeline where, say, the 3 generation of those nutrients could be harvested and applied to food crops.
Sewage is heavily treated in most places these days - usually by a biological process. The suitably sterilized solid waste can indeed be used as fertilizer.
I don't see any reasonable argument why they should not be able to remove at least sizeable parts of drug residues. There is metabolism in the human body and the is bacterial metabolism. Organic matter will be broken down at least partly.
Sand in fungally dominated soils show signs of biological erosion similar to you see under lichen. What we can take from this is that soils under perennial woody crops can mine their own minerals, probably until the sun runs out of hydrogen.
But annual crops mostly grow either in prairie or disturbed soil ecosystems. Bacterially dominated soils. So any way you slice it, we need a wider mix of perennial and woody crops. Over a long enough time horizon, all of your fertilizer resembles compost and that compost has to derive its minerals from fungal soils.
* do everything possible to keep the life in the soil alive: do not use pesticides, funghicides or herbicides since the toxins are not specific and kill all soil life.
* aerate the soil to have enough oxygen (O2) and nitrate (N2) in the soil. Use a broadfork, but only with compacted soil.
* do not plow since that breaks the networks of funghi and ultimately deteriorates the performance of plants.
Want to know more? See the video "Restoring Soil Biology, Increasing Yields and Reducing Costs" by Dr Elaine Ingham: https://www.youtube.com/watch?v=pk14Qyulc9E