Earthquake scientists reveal how overplowing weakens soil at experimental farm (washington.edu)

by Brajeshwar 116 comments 212 points
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116 comments

[−] WaitWaitWha 51d ago
Just to be clear, plowing and tilling are not the same thing, and this article implies the researchers might be using it interchangeably. They bundle different soil-disturbance practices together, irrelevant of their uses, and potential compaction impact. Of course, tilling can also just be used as a generic term for all of the soil management in farms, but this is never explained.

It is also unclear if the paper is removing traffic compaction or it is part of their results. when an MF 8700 with 23,800 pounds rolls around it will compact things. A lot. I have a lunch box to prove it.

Would love to see no-till vs shallow till vs deep plowing. For this paper, they should have introduce and have primary conclusion around the technical data gathering as a novel idea, not draw conclusion from the collected data.

The physics and sensing seems rigorous. Understanding of agricultural taxonomy, farming, is coarse at best. 40 hours of total data during rain is a wee bit short. 2cm depth for the fiber is only going to sense near- or surface. Most crops go deeper than that. Single-site experiment on a single type of soil is very narrow.

To me, plowing (like a chisel plow or moldboard) is to break up soil, and 'folds' old crop like corn stalks back in. It is also the first step for never-used land prep for growing stuff. Usually, beginning of season, compacting, or new site. 8 to 20 inches deep. can flip the soil upside down.

Tilling gets the soil ready for seed, aeration, crumble large lumps and fill larger gaps on the surface, or mix fertilizer/compost into soil. 4 to 12 inches deep.

Discing aka harrowing (disc harrow) usually will cut the remaining roots a few inches deep, often done post plowing. good for putting last years leftovers just a few inches under. 4 to 6 inches.

Note that it seems that as the field size gets smaller, the tilling vs harrowing seems to flip? At least how people consider using them.

(edit: I am all over with this one, but I think the gist comes through.)

[−] tecleandor 51d ago
If you check the paper, it doesn't say "plowing" anywhere. Just tilling. And these are the parameters:

> Tillage had been applied at three depths commonly used in farming—no tillage, 10 cm, and 25 cm—while compaction had been imposed using two tire pressure levels—70 kPa for both front and rear tires, and 120 kPa for front and 150 kPa for rear tires.

[−] universa1 51d ago
What one has to keep in mind as well, that even though tractors are really heavy they spread that weight across a large area (using low tire pressures and having massive tires to begin with). So, iirc, the per area impact is even lower then a human. It impacts a lot larger area, though!

Plowing vs tilling is also very much about soil erosion and depends very much of the location you are in.

[−] bluGill 51d ago
Compaction is sublinear with weight, make the tractor heavier so it combacts more makes a small difference where the tires are - but you can now pull something bigger (assuming horsepower) and that means less of the field is touched by tires and in turn less compaction. compaction is worse where the tires touch but they touch less.

the above is also why tires are better than tracks in many cases. The tire has more compaction, but when you turn it touches less land and so overall is better than a track.

of course every soil is different. For details of you particular land you need an expert who knows your soil.

[−] bell-cot 51d ago
This is why I try to look at the HN comments first. Then, maybe look at the article.
[−] swores 51d ago
I often do to, so this reply is not a criticism of your general point, however in this case your would have been better informed to read the actual thing and not the comment you replied to!

https://news.ycombinator.com/item?id=47529291

[−] bell-cot 51d ago
Yeah. But with a finite lifetime, and an effectively infinite supply of content on the internet - quick & dirty attention-rationing algorithms are unavoidable.
[−] speefers 51d ago
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[−] turtlesdown11 51d ago
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[−] WaitWaitWha 49d ago
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[−] speefers 51d ago
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[−] heathrow83829 51d ago
to till or not to till, that's the question. one way to look at is check the yields that result from dig vs no dig. Charles dowding did exactly that. for seven years he had two plots, one where he dug and one where he didn't. in each one he added the same amount of compost and grew teh same crops on both sides.

Overall, the nodig plot harvest 10% more. but here's where it gets interesting. those yields were not uniformly spread across the vegetable types. if you dig into the data, you'll see, some did quite worse with dig and some did quite better. guess which ones did better on dig? Potatoes, Rutabagas, carrots and parsnips and cabbage all did better in Dig! roughly to the tune of about Potatoes 21%, carrots 21%, Rutabaga 14%, Cabbage, 11%, broad beans 10% better. it's all published in his books. Everything else did better with no dig. Shallots especially did 33% better with no-dig, ales 21% better, onions 22% better with no dig.

[−] chongli 51d ago
The no dig method has taken on a life of its own, almost a religion. It's probably a mistake for most people though. "One dig" is almost always going to be superior, given soil that has never been used for gardening before. Trying to start a no dig garden in some heavily compacted, organic-poor, heavy clay soil is going to lead to extreme disappointment.
[−] cyberjar 51d ago
I thought that was always the case. Dig as required to get your soil to the correct type for what you want to grow, then let it be and don't dig.

Digging to turn the soil seems like an old adage that has been passed down through generations, but modern scientific studies are now showing it provides very little to no benefit for yields.

[−] hansvm 51d ago
Man, I wish I had access to heavily compacted, organic-poor, heavy-clay soil. It's the 80% rock that makes even basic tasks a day-long chore.
[−] vlachen 51d ago
A friend of mine retired from the military and moved to my neck of the woods in the Ozarks. Having lived in Eastern North Carolina for most of his 20 years in, he had gotten used to sandy soil with nary a rock. Prior to that, he was in the Twin Cities of Minnesota, and I don't think he dug many holes there.

After closing on their new house he asked me for a shovel, for which to install a mailbox. Of course I'd help my friend out. "Sure, buddy!" I said. "Here's a shovel, post-hole digger, pickax and a rock-bar. That should get the job done." After I explained to him that yes, you need a 20 pound pointy chunk of steel to dig any sizable hole around here, he still didn't quite believe me. However, once he got the mailbox planted, he adjusted his beliefs accordingly.

On the rare occasion that I have to dig a hole somewhere with actual dirt, I always find myself amazed at how easy it is. Those times help me understand scenes in TV or movies that include someone digging a hole. Those scenes don't ever depict someone deciding to move whatever it is they're putting in the ground because they hit a massive stone at 8 inches into a 24 inch hole, and there ain't any getting through it. The scenes don't depict the Herculean effort required to just plant a tree. Those shows don't show the absolutely back-breaking labor it takes to be a landscaper around here. And before I had the chance to do the same kind of work in actual soil, those scenes just didn't make sense.

[−] hansvm 48d ago
I suppose I shouldn't be surprised that complaints of rocks where you expect soil invite other Ozarkians. That was something that shocked me about the Midwest in comparison; even with a concerted effort, I couldn't find enough of a rock to fill a slingshot.
[−] arethuza 51d ago
Our house sits on a small basalt volcanic plug and the solid dark rock lurks not very far under our garden - 100m north of us and its sandstone, 100m south and it is limestone.

Digging a hole of any depth would probably require explosives!

[−] cucumber3732842 51d ago
I'd save a fortune on concrete and rebar if I had high quality bedrock so close.
[−] vlachen 51d ago
Hard pass. Karst limestone is bad enough.
[−] chongli 51d ago
The soil in my backyard has very few rocks but the clay is so hard and dense it may as well be a brick wall.
[−] thatcat 51d ago
When it's wet, but not saturated - like 1-2 days after a rain - you can decompact the soil with a strong metal broadfork and leave the soil in large block aggregates. This keeps the soil structure and maintains some fungal web connections. Add nutrients, wood chips, stick and sand below aggregates and in cracks. Cover with compost and plant clover to cover.
[−] greazy 51d ago
This is amazing info thank you.

What is the purpose of planting clover?

[−] pja 51d ago
Clover is a nitrogen fixing plant - used to be that you’d plant clover for a year in between other crops to make your soil fertile again.

(It’s the bacteria in the roots that do the actual nitrogen chemistry.)

[−] Angostura 51d ago
Really good advice above. But if you want to cheat a bit, I used https://www.thompson-morgan.com/p/vitax-clay-breaker--25-kg-... on my heavy clay garden and it helped a lot, in combination with extra organic material etc.
[−] thatcat 46d ago
this is just gypsum in case anyone was wondering
[−] thatcat 51d ago
Clover fixes nitrogen and roots help stabilize the voids in the soil. They sell seed mixes called "ground cover mix" that includes other plants and will help keep the soil from recompacting when it rains and keeps weeds at bay.
[−] darkarmani 51d ago
Are you sure it is just clay? Sandy clay packs even tighter than just clay: https://www.uaex.uada.edu/farm-ranch/crops-commercial-hortic...

"If you mix sand into clay, the clay particles will fill in all the open spaces between the sand particles and often the clay will act as a ‘glue’ sticking all particles together, ultimately resulting in a more dense soil."

[−] chairmansteve 51d ago
"Trying to start a no dig garden in some heavily compacted, organic-poor, heavy clay soil is going to lead to extreme disappointment".

For sure. In Dowdings method you put a quite thick layer of compost on top of the existing soil. You then top up the compost every year.

[−] chabska 51d ago
Oh yeah, just top up the compost every year. Where are you getting that compost from? Wood chips you say? You'd have to denude ten acres of forest to make enough compost to Dowding one acre of field.

He's a soil vampire, sucking in fertility from somewhere else to feed his own garden.

[−] tbossanova 51d ago
Raised planters can help too
[−] fuzzy_biscuit 51d ago
We call that New Jersey here!
[−] jimnotgym 50d ago

> Trying to start a no dig garden in some heavily compacted, organic-poor, heavy clay soil is going to lead to extreme disappointment.

If you start with Charles Dowdings 6 inches of compost on top, that is not necessarily true. The soil comes to life as worms go mad pulling that compost down into the soil.

It actually works rather well. Year 1 can be very good. Year 2 even better.

The real disappointment in Year 1 is the amount of weeds that find 6 inches of compost no barrier at all! With digging you can get a lot of perennial weed roots out, and hoe off the annuals. With no dig you have to pull them.

I'm not a idealogue, so actually suggest glyphosate before compost...but people don't normally like that suggestion.

[−] ikidd 51d ago
The biggest difference in no-till is water infiltration and retention. The next is ability to work land earlier with equipment that would sink in tilled soil when wet. Another is less equipment passes, for fuel use as well as owning the equipment needed to do those passes.

On the con side, no-till trades diesel for spray costs.

[−] bluGill 51d ago
A general rule of thumb is when you switch corn from to to notill for the first seven years yields will be worse, but in the eighth year and after they are better.
[−] samirillian 51d ago
The one straw revolution guy planted root vegetables among fruit trees in orchards I wonder if that would make a difference
[−] ErroneousBosh 51d ago
It's almost like all arable land and all arable crops aren't identical and trivially interchangeable, eh?
[−] prewett 51d ago
I think the article's theory on why people plow is wrong: it is not to let the soil hold more water, but to get rid of weeds. I know someone who did no-till for a while, and he found that you have to spray with glyphosate to keep the weeds down. Eventually the weeds that had evolved to be glyphosate-resistent spread to his area, and he had to go back to regular plowing. He said that the no-till really improved the soil, though.
[−] altairprime 52d ago
Given the discovered ability of fiberoptics to sense water content, a kind of fiber fabric could be deployed to sense water levels across an entire field at the cubic yard level. The sensing controller would end up resembling an LCD addressing controller in reverse, with row/column/subpixel (sub-terranean-pixels!) breakout. Not that pixel-addressed farm fields are going to be efficient to work yet, lacking both processes and tooling for soil, seed, and harvest — but with sensing- and tool-assisted farming, we ought to be more able to harness the soul that we have without destroying it with the sledgehammer-nail “till the whole field” approach.
[−] regus 51d ago
Overplowing is what created the dust storms of the Great Depression Dust Bowl era.
[−] CrzyLngPwd 51d ago
That heavy clay soil in the main photo looks awful.

I have around 45 acres of heavy clay, poor agricultural land, which would look very similar to that if we allowed heavy machinery, or even an ATV, on it when it is sodden.

[−] nodesocket 51d ago
I admit farming knowledge is not my strong suit, but I thoroughly enjoyed the Amazon series Clarkson’s Farm. If you want to see a country destroy its agriculture industry, look no further than the UK. Their shortsightedness, bureaucracy, and blind acceptance of doomer environmentalists essentially bankrupted farmers in the country side.
[−] ggm 51d ago
Angus Calder "the people's war" about the british home front in WW2 notes older farmworkers in the south downs virtually crying as land which had been unploughed since the norman conquest was put to the plough because of grain shortages from the U boat war.

Maybe they knew a thing or two (low earthquake zone, it has to be said)

[−] monkaiju 52d ago
I realize this exact data might be novel, but haven't we know that till-reliant farming was detrimental to soil for a long time? The no-till people are a huge part of the permaculture movement, also theres always folks talking about how important fungal networks are and how they're largely destroyed by tilling.

I mean even Karl Marx talked a ton about soil health and while he mostly talked about "metabolic rift" not tilling (that I know about) specifically it seems like a similar focus on short term output vs long term soil health.

I guess I'm just not clear on if there is actually a new serious problem being "revealed" as the title says or just being substantiated further.

[−] worthless-trash 51d ago
Zero / minimal tillage has been a thing for decades, im surprised this is news.
[−] destitude 51d ago
Let alone the wind erosion from having exposed soil over winter.
[−] PunchyHamster 51d ago
...isn't loosening the soil the entire point of plowing ? Like, congratulations, you have discovered what farmers already knew.

Also, just plowing is pointless, the point is to grew plants better, ignoring that and just looking at moisure at some level is pointless

[−] aaron695 51d ago
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[−] trusted_brother 51d ago
Yes this is entirely true and we must ban farming immediately.