The world needs topsoil to grow 95% of its food – but it's rapidly disappearing | Hacker News Reader

The world needs topsoil to grow 95% of its food – but it's rapidly disappearing

theguardian.com

61 pointsmettamage32 comments

I just talked to someone who is pretty knowledgeable about issues regarding:

Global warming

Too few trees reuptaking water

Top soil being depleted

He said that top soil being depleted is arguably the worst problem of the three. So I simply looked up the first recent article about it and submitted it.

I have never heard of this issue and I suspect many of you haven’t either.

Disclaimer: the person I talked to has a startup that replants trees in very innovative ways (by using robotics and by employing techniques so that plants can uptake water way deeper from the ground than normally). I am not affiliated with him, I simply met him at a dinner party.

Hey thanks for posting this, can you link that persons startup as well? It sounds interesting.

One starup he has is called the Land Life Company, I made a submission out of it since I think it's really cool [1].

The other one is called Sensoterra [2].

[1] https://news.ycombinator.com/item?id=20421771 -- "Our mission is to reforest the world's 2 billion hectares of degraded land" (apologies if you just want the link immediately)

[2] https://www.sensoterra.com/ -- "Wireless soil moisture sensors: make better irrigation decisions for increased yield, with smart soil moisture measurements"

This isn't really new. Top soil in cut down rain forests barely lasts two years of harvest.

I'm certainly no expert, but topsoil depletion scares more than any other environmental problem - it can take a few centuries to replace an inch. Even in the absence of climate change we'd be heading for trouble but increasing temperatures are only going to increase the rate of depletion.

I am no expert either, but you can make compost pretty easily in far less time. Its good for growing plants.

Could composting on a large scale be a solution?

No, compost is just organic material. Good top soil has <10%-20% organics by volume. Also, since the organics in compost will break down over time, they will need to be re-applied. Sand and clay are needed for structure and minerals.

I’d like to recommend the documentary The Biggest Little Farm. Among other things it illustrates the contrast between industrial farming and its soil treatment (optimized for cost and short term profit) and alternatives (rebuilding rich soil which captures water etc.)

It’s incredibly inspiring.

Topsoil loss is a major problem for the environment, but it is worth pointing out that we do not need topsoil to grow food. We have hydroponics and aeroponics and a range of other solutions that do not use land in traditional ways. There is also reason to believe that an increasing fraction of our food will be grown in this way rather than on the land if only because the vast majority of farmable land is already farmed.

Where do you think the plants' nutrients come from in those growing methods? Petrochemical plants also set to run out of resources. You're adorable.

Look at permaculture food forests and how they rebuild topsoil. While we still can.

> Where do you think the plants' nutrients come from in those growing methods?

To answer this question we should look inside ourselves

That's exceptionally snarky... Btw, are you implying that the aquaponic nutrient additives come from topsoil?

Mostly? We mine minerals and refine them with:

Petrochemical sources.

Which, you might also worry about running out of, in about as short order as topsoil.

There was another commenter here with more expertise on actually growing things this way - they suggested that leafy greens were the only thing we could grow efficiently with this method. Which does have a certain air of "truthiness" to it.

Sorry I misinterpreted your post. I'd like to mention again that your "you're adorable" is very patronizing and disrespectful.

Only crops that are mostly water (lettuce, tomatoes) can be economically grown hydroponically. We need topsoil to grow cereals (corn, wheat etc).

Given that cereals tend to not be too good for us ... maybe we should limit them anyways?

Perhaps but we also use cereals and row crops to feed livestock (corn), make vegetarian protein (soybeans, canola, wheat) and make our clothes (cotton). None of these can be grown hydroponically.

Hemp gives you all those things and grows extremely well hydroponically.

More importantly, hemp grows well in poor soils.

It's not the water content per se I think, most herbs thrive in this medium as well. Most probably the crops' price and growing speed are the deciding factors.

Oh, and check this anecdote out: https://www.thenational.ae/uae/from-paddy-fields-to-uae-dese...

Once topsoil is depleted, the economics change drastically.

Point is, we won’t starve. But we will need to expend more resources gathering food.

> 'If we continue to degrade the soil at the rate we are now, the world could run out of topsoil in about 60 years, according to Maria-Helena Semedo of the UN’s Food and Agriculture Organization.'

I don't personally find these type of 'we only have x years to save y!!!!' statements have much impact on me any longer because firstly there seems to be a new one every week, and secondly humanity would act to prevent whatever cataclysm is prophesied (as it is, in fits and starts, with climate change).

And on this one in particular, and as I always say when it comes to ecological catastrophes: what about population control?

As for topsoil - it has happened before.

Whether we're talking about multi-continental with the bronze age collapse, or we're talking corporate with the US Dust Bowl, people always ask - why didnt anybody do something?

You're assuming people knew there was something to do. You're assuming the people with those means were not instead racing to extract the most profit, just like an oil company.

One local-scale solution is really quite simple, but doesn't lend itself to industrialized single-crop agriculture. Look for "permaculture food forests" in you favorite search engine. Maybe see the results on youtube.

By planting pines with deep taproots, and cutting them off at 6' tall once a year and leaving the yearly growth to rot, you feed the topsoil from above. With the nitrogen-and-phosphorous fixing symbiosis at those same pines' roots, you feed the topsoil from below.

This process takes decades, instead of centuries, because it is deliberate. You can get a head start - now - for you and yours.

[flagged]

That's not what I'm saying at all! I'm firstly criticising the use of a particular rhetorical device that I think has become ineffective, and secondly pointing out the inconsistency when those that would advocate all kinds of draconian interventions in our daily lives yet refuse hysterically any contemplation whatsoever of controlling our numbers as a species.

While reducing population is necessary and helpful, humans’ ability to consume is infinite, especially as it is a good proxy for power and hence a mating signal. An attitude change in our want to consume is also necessary.

Could you please stop posting in the flamewar style to HN? and also not use the threads here for ideological battle? These things degrade communication between people and are generally not what this site is for.

https://news.ycombinator.com/newsguidelines.html

Yeah, this is the tradeoff of HN -- Just about anybody can get a wild headline to the frontpage.

Sometimes this is great, because that wild headline is an important truth that is ahead of what we normally take seriously. But 90%+ of the time it's non-replicable crap you'll never see again (e.g. cancer almost cured for the 3,125th time!)

Why would it not be possible to switch to aquaponics?

I'm assuming the cost would be greater but this article makes it seem like the world would end and there wouldn't be any way of growing nutritious food.

Aquaponics demands a LOT more resources. Petrochemical fertilizers to dissolve in massive amounts of water... This does not sound like a way to sustain a society into perpetuity.

Do you have any links? Because as far as I can see we can easily grow larvae from biomass (including food scraps) and we can feed larvae to fish. I guess throw some genetic engineering in there and it should work. What am I missing?

"I guess throw some genetic engineering in there and it should work."

If you are a programmer, you should have felt a pang of sympathy for the biologist who is in the background screaming "that's not how it works".

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