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262 points gnabgib | 1 comments | | HN request time: 0.213s | source
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ralusek ◴[] No.43744184[source]
I'm a gardening and landscaping enjoyer, but I am constantly confused about the bordering magical thinking surrounding dirt, among other aspects of growing things.

If you look at hydroponics/aeroponics, plants basically need water, light, and fertilizer (N (nitrogen) P (phosphorous) K (potassium), and a few trace minerals). It can be the most synthetic process you've ever seen, and the plants will grow amazingly well.

The other elements regarding soil health, etc, would be much better framed in another way, rather than as directly necessary for plant health. The benefits of maintaining a nice living soil is that it makes the environment self-sustaining. You could just dump synthetic fertilizer on the plant, with some soil additives to help retain the right amount of drainage/retention, and it would do completely fine. But without constant optimal inputs, the plants would die.

If you cultivate a nice soil, such that the plants own/surrounding detritus can be broken down effectively, such that the nutrients in the natural processes can be broken down and made available to the plant, and the otherwise nonoptimal soil texture characteristics could be brought to some positive characteristics by those same processes, then you can theoretically arrive at a point that requires very few additional inputs.

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greenie_beans ◴[] No.43744301[source]
sure, we can make them grow well in a lab. but a natural system is so much simpler and elegant
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westurner ◴[] No.43744417[source]
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.

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throeijfjfj ◴[] No.43745053[source]
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!

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1. westurner ◴[] No.43752265[source]
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?