Comment by westurner | Hacker News Reader

Comment by westurner | Hacker News Reader

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Plants absorb nitrogen and CO2 from the air and store it in their roots; plants fertilize soil.

If you only grow plants with externally-sourced nutrients, that is neither sustainable nor permaculture.

Though it may be more efficient to grow without soil; soil depletion isn't prevented by production processes that do not generate topsoil.

JADAM is a system developed by a chemicals engineer given what is observed to work in JNF/KNF. https://news.ycombinator.com/item?id=38527264

Where do soil amendments come from, and what would deplete those stocks (with consideration for soil depletion)?

(Also, there are extremely efficient ammonia/nitrogen fertilizer generators, but still then the algae due to runoff problem. FWIU we should we asks ng farmers to Please produce granulated fertilizer instead of liquid.)

The new biofuel subsidies require no-till farming practices; which other countries are further along at implementing (in or to prevent or reverse soil depletion).

Tilling turns topsoil to dirt due to loss of moisture, oxidation, and solar radiation.

The vast majority of plants do not absorb nitrogen from the air. Legumes are the well-known exception.

It isn't legumes that absorb nitrogen from air. It is bacteria that lives on their roots.

That is true but legumes actively foster those bacteria on their roots and without the legumes most of that bacteria dies. Its a symbiotic relationship.

That, and most of the other nutrients which was needed to grow the vegies ( like phosphates and potassium) are flushed into the toilet. There will be no long term permaculture without cycling those back at some point. Otherwise, organic or not, this will remains an wasteful open loop.

I think that's why it's good to rotate beans or plant clover cover crop.

Three Sisters: Corn, Beans, Squash: https://en.wikipedia.org/wiki/Three_Sisters_(agriculture)

Companion planting: https://en.wikipedia.org/wiki/Companion_planting

Nitrogen fixation: https://en.wikipedia.org/wiki/Nitrogen_fixation

From https://news.ycombinator.com/item?id=43764441 :

> "Discovery of nitrogen-fixing corn variety could reduce need for added fertilizer" (2018) https://news.ycombinator.com/item?id=17721741

Most plants do not absorb atmospheric nitrogen, but need external nitride fertilizer to grow! That causes serious ground water polution!

> The new biofuel subsidies require no-till farming practices

This actually depletes soil of nitrogen!

Why do you believe that no-till farming practices deplete soil of nitrogen more than tilling?

A plausible hypothesis: tilling destroys the bacteria that get nitrogen to plant roots.

Isn't runoff erision the primary preventable source of nitrogen depletion?

FWIU residue mulch initially absorbs atmospheric nitrogen instead of the soil absorbing it, but that residue and its additional nitrogen eventually decays into the soil.

I have heard that it takes something like five years to successfully completely transform acreage with no-till; and then it's relatively soft and easily plantable and not impacted, so it absorbs and holds water.

No-till farmers are not lacking soil samples.

What would be a good test of total change in soil nitrogen content (and runoff) given no-till and legacy farming practices?

With pressure-injection seeders and laser weeders, how many fewer chemicals are necessary for pro farming?

tilling with anything more than human power should be banned!

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