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Earth United States Science

Midwestern US Has Lost 57.6 Trillion Metric Tons of Soil Due To Agricultural Practices, Study Finds (phys.org) 153

An anonymous reader quotes a report from Phys.Org: A new study in the journal Earth's Future led by the University of Massachusetts Amherst shows that, since Euro-American settlement approximately 160 years ago, agricultural fields in the midwestern U.S. have lost, on average, two millimeters of soil per year. This is nearly double the rate of erosion that the USDA considers sustainable. Furthermore, USDA estimates of erosion are between three and eight times lower than the figures reported in the study. Finally, the study's authors conclude that plowing, rather than the work of wind and water, is the major culprit.

Using an extraordinarily sensitive GPS unit that looks more like a floor lamp than a hand-held device, the team walked dozens of transects, or perpendicular routes across the escarpment, from the untouched prairie to the eroded farm field, stopping every few inches to measure the change in altitude. They did this hundreds of times throughout the summers of 2017, 2018 and 2019. Once they had their raw data, the team used historical land-use records and cutting-edge computer models to reconstruct erosion rates throughout the Midwest. What they discovered is that Midwestern topsoil is eroding at an average rate of 1.9 millimeters per year. Put another way, the authors estimate that the Midwest has lost approximately 57.6 trillion metric tons of topsoil since farmers began tilling the soil, 160 years ago. And this is despite conservation practices put in place in the wake of the Dust Bowl in the 1930s.
As noted above, much of the erosion was due to tillage, or plowing. "The modeling that I do shows that tilling has a 'diffusive' effect," says Jeffrey Kwang, a postdoctoral researcher at UMass Amhers. "It melts the landscape away, flattening higher points in a field and filling in the hollows."

Furthermore, the USDA doesn't include "tillage erosion" in its own analysis, meaning it's drastically underestimated the rate of erosion that's occurred in the area. The team suggests that more sustainable practice, such as no-till farming and soil regeneration, "will likely be required to reduce soil erosion rates in the Midwest to levels that can sustain soil productivity, ecosystem services, and long-term prosperity."
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Midwestern US Has Lost 57.6 Trillion Metric Tons of Soil Due To Agricultural Practices, Study Finds

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  • We will likely take steps to alleviate this issue right after we've depleted all of the useful soil and Canada is the new breadbasket. Maybe. If we feel like it.
    • by ShanghaiBill ( 739463 ) on Wednesday March 16, 2022 @11:14PM (#62365299)

      The solution is no-till farming [wikipedia.org].

      No-till farming not only reduces erosion by an order of magnitude, but also reduces labor, fuel consumption, and capital expenditure. You don't need to buy a plow and harrow if you don't plow.

      No-till techniques currently work better with GMO crops and rely on herbicides such as glyphosate (Roundup) for weed control. In the near future, agricultural robotics can use intelligent weed control to eliminate most herbicide use.

      About 20% of American farms are already using no-till.

      • I like that article. I saw a link to a related option, Strip tilling [wikipedia.org]. It is a balance between no-till and full till methods, with some benefits above both. It does require more reliance on GPS guidance of the tractor but has some advantages such as only fertilizing the area that has the seeds and leaving some areas untilled.

        No-till techniques might to be a problem when you do crop rotation. Trying to plant cereal grains in a field that previously had alfalfa or corn would be a problem with no-till pract

        • I saw a link to a related option, Strip tilling [wikipedia.org].

          That is interesting. I hadn't seen it before.

          It does require more reliance on GPS guidance of the tractor

          GPS guidance for tractors is very common, so that isn't a big problem.

          Trying to plant cereal grains in a field that previously had alfalfa or corn would be a problem

          The corn stalks are cut, chopped, and dispersed as a ground cover during the harvest.

          Alfalfa is a bigger problem because the roots survive over the winter and resprout the following spring. Fields are often left in Alfalfa for a decade or more before rotating. When you are ready to rotate, the main options are plowing or herbicide.

          Another practice is to rotate from alfalfa into another forag

      • All hail Monsanto!
      • by vlad30 ( 44644 )
        The wiki article is good and suggests that although the USA is behind No-till is picking up pace. and the problem will decrease.

        My question where did it go ? a rough calculation says that is about 30,000 cubic kilometres of soil

        is there a carpet somewhere that's hiding this?

        and using the above 2mm/yr that equates to 3.2 meters in height lost on average which would mean some objects like farmhouses built years ago would visibly be higher than they were when built over 100 years ago.

        is it possible over

        • The wiki article is good and suggests that although the USA is behind No-till is picking up pace. and the problem will decrease.

          My question where did it go ?

          Down the rivers and to the ocean or wherever we put it after dredging the waterways. In the former, creating delta land.

          and using the above 2mm/yr that equates to 3.2 meters in height lost on average which would mean some objects like farmhouses built years ago would visibly be higher than they were when built over 100 years ago.

          They might be. It's an interesting idea to look at. Now there isn't tilling right near the farmhouses, so it would make a great school experiment.

          We also have the issue of possible subsidence based on the depletion of the groundwater.

          I've been doing some searches, but they are dominated by land subsidence in California and Houston Tx. But I'll keep looking.

          • There are definitely fencerow areas in the Midwest where no tillage has been done and you can see elevation differences of a few feet in some locations on one side of the fence versus the other. It also says as much in the original article.
        • by Chaset ( 552418 )

          2mm/yr x 160 yr = 320mm = 32cm. != 3.2m

        • by Rhipf ( 525263 )

          and using the above 2mm/yr that equates to 3.2 meters in height lost on average

          You must be from the US and not used to metric measurements (just kidding).
          Your calculations are off by a factor of 10. It wouldn't be 3.2 meters but 32 centimeters (2mm/yr=0.2cm/yr=0.002m/year over 160 years equals 32cm=0.32m). Still a considerable amount but a lot less than your calculated depth.

        • Not 2 centimeters, 2 millimeters. The loss is a bit more than a foot of soil on average.

      • The solution is no-till farming [wikipedia.org].

        No-till farming not only reduces erosion by an order of magnitude, but also reduces labor, fuel consumption, and capital expenditure. You don't need to buy a plow and harrow if you don't plow.

        No-till techniques currently work better with GMO crops and rely on herbicides such as glyphosate (Roundup) for weed control. In the near future, agricultural robotics can use intelligent weed control to eliminate most herbicide use.

        About 20% of American farms are already using no-till.

        If no till and irrigation are used like it probably speeds up soil salinization. Even back in the 1990's when I had a rare coast to coast clear sky flight, I was shocked at the number of white "dots" on the midwest landscape.

        Now it might make it easier to scrape off the top layer of soil and discarding it. But then we exacerbate the problem by purposely getting rid of topsoil in addition to erosion.

        • by Rhipf ( 525263 )

          Those "white dots" you saw from your airplane vantage point probably weren't salt concentrations. You would need a hell of a lot of irrigation to produce visible salt deposits from the height of a commercial jet.

          • Those white dots are most likely confined animal feeding operations. I used to work in one and they almost all have white steel roofs. They're all over Iowa but not as much in Nebraska and Kansas.
      • by kackle ( 910159 )

        No-till techniques currently work better with GMO crops and rely on herbicides such as glyphosate (Roundup) for weed control.

        That [sciencedaily.com] concerns [cnn.com] me.

      • âoe No-till techniques currently work better with GMO crops and rely on herbicides such as glyphosateâ

        No they donâ(TM)t, as is clearly obvious when you consider that no-till farming in the EU, where almost all GMOs and glyphosate are banned, is very much a thing.

        • People are also doing organic no-till using a "roller-crimper" to mow the cover crop and turn it into mulch.

    • "Operations to liberate the Northern Corporate Appendage commenced at 0600. The wheat must flow!"

    • by dbialac ( 320955 )
      We've been plowing the earth for thousands of years, including leaving fields empty of plants during winter seasons. As such, I doubt there's a sudden drop in field levels in the last 160 years.
      • by noodler ( 724788 )

        We've been plowing the earth for thousands of years, i

        Yeah, i myself was born into a 3000 year old lineage of tractor manufacturers...

      • I don't think the midwest has had widespread tilling for thousands of years. Your knowledge of history doesn't seem to be quite up to the task of supporting your idea.

        Related: DId you ever wonder why it is called the "midwest" instead of the "mideast?" And did you wonder when it started to be called that?

      • Right? I mean, everyone knows that the Sioux Nation was operating windrowers and combine harvesters for several hundred years before white europeans showed up. There used to be herds of tens of thousands of buffalo that would just roam right through the middle of your soybean fields and it really fucked up your crop yields!

        Wait, you know we're talking about the american Midwest, right? And that agricultural methods have changed substantially since the industrial revolution? And not in a way that conserv

  • This is America, we use basketball superstar Michael Jordans.
    • Metric or not, TFA is completely wrong about the quantity.

      The land area of the Midwest is 730,000 square miles. Soil density is commonly 1.3g/cm^3. Plug this into GNU units:

      You have: 2mm / year * 160 year * 730000 mile^2 * 1.33 g/cm^3
      You want: 57.6 Ttonne
      * 0.013970108
      / 71.581407

      This answer is 71 times smaller than the value in the article, and that doesn't even account for the fact that not *every* square inch of the Midwest is tilled fields.

      • This answer is 71 times smaller than the value in the article, and that doesn't even account for the fact that not *every* square inch of the Midwest is tilled fields.

        Not to mention the percentage which is tilled fields has changed drastically over the course of the 160 years of their alleged estimate, both waxing and waning depending on the era. In the past 20 years, tilled farmland in the US has gone from 945,080 acres to 895,300 acres. Much of that loss is due to what is usually termed "urban expansion" though in practice it means expansion of suburbs.

        I'd say these researchers have fallen victim to extrapolation fallacy [xkcd.com].

  • Yields have only increased on these plains that would be desolate without modern agriculture. So-called "sustainable" practices aim to increase costs and reduce yields so that the malthusians can create their self-fulfilling prophecy of declining populations with starvation to "protect" this part of the Earth that would be otherwise unusable.

    Get over yourselves. Humans need to eat and we have the technology to feed them. We are not going to stop farming this land to its maximum capacity.

    • Farmland wears out. Some ancient agricultural regions are now desert.

      But for the US great plains farm belt, the problem is going to come when the aquifers are used up for irrigation. No water, no breadbasket.

      And then there's the issue of global warming. Due to changes in rainfall patterns I expect some good farmland to become desert, and some poor land will become new breadbaskets. Some food "haves" will become "have-nots".

      And there will be wars over it...

    • That's pretty salty for someone who doesn't know what they're talking about. Even at its best, where some sewage sludge is applied (so not all fertilization is done with petroleum-derived fertilizer) and where crop rotation is used, corporate mechanized farming destroys farmland in two major ways. One is that the heavy machinery creates hardpan which traps water, creating anaerobic conditions which (when coupled with synthetic fertilizers) destroy soil diversity. Good soil is made up of 60% or more LIVING o

    • by gtall ( 79522 )

      See the Aral Sea and what Soviet methods for growing cotton did to it, the land, and the people. A good part of what was under water is now toxic wasteland. Creating another dustbowl in America's breadbasket is not a wise decision.

  • by Vegan Cyclist ( 1650427 ) on Wednesday March 16, 2022 @11:57PM (#62365353) Homepage

    "Most cropland is used for livestock feed, exports or is left idle to let the land recover."

    127.4M acres used for livestock feed.
    77.3M for human crops.
    38.1M for biodiesel shockingly.

    I'm sure I'll get grief for the very vegan-leaning source: https://www.bloomberg.com/grap... [bloomberg.com]

    • 38.1M for biodiesel shockingly.

      This is surprising, given that biodiesel is so rarely used given how terrible it is for diesel engines.

      • The 38.1M acres include both biodiesel and ethanol.

        99% of it is likely corn for ethanol production, not biodiesel.

        • The 38.1M acres include both biodiesel and ethanol.

          99% of it is likely corn for ethanol production, not biodiesel.

          Ok, now that makes sense.

      • In Europe basically you can basically no longer buy fuel without a "bio" component. It is now at a minimum of 5% to 8%,
        Even the "Super" 99 or 100 octane fuel has ethanol inside.

        • by Goatbot ( 7614062 ) on Thursday March 17, 2022 @05:26AM (#62365685)
          They actually use the ethanol to boost the Octane ratings. Which isn't necessarily a bad thing until you realize that ethanol loves to attract and absorb water. Petrol engines apparently do not like to burn water.
          • > ethanol to boost the Octane ratings.

            Ethanol doesn't contain octane. Ethane with an alcohol group.

            • Not sure how you arrive at that. Pretty well known that the octane rating of ethanol is 100 and when mixed with gasoline rises to 112 or something. That said I am not a chemist.
              • Pretty well known that the octane rating of ethanol is 100 and when mixed with gasoline rises to 112 or something. That said I am not a chemist.

                Me neither. So I looked it up...

                An octane rating [wikipedia.org], or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates gasoline's capability against compression.

                [...]

                Octanes are a family of hydrocarbons that are

            • The so-called "octane rating" (in relation to gasoline) is in fact the "resistance to self-ignition (self-detonation) when a mix of evaporated gasoline and air is compressed".
              To protect the engine from "knock", you want the fuel-air mix to burn (explode) only after spark is applied.

              It does not refer to the "methane, octane, butane, propane, ..." chemical formulas of carbon-hydrogen molecules.

            • An "octane rating" does not quantify how much octane is in the fuel. It is a measure of the fuel's ability to withstand compression without detonating (which is why a high octane rating will prevent engine knock, which is fuel detonating in the engine cylinders prematurely). Octane is particularly good at this, hence the name, but any liquid fossil fuel will have an octane rating, and it is possible for a fuel to have a good octane rating while having no octane in it. https://en.wikipedia.org/wiki/... [wikipedia.org]

            • Octane rating, not necessarily octane itself. Resistance to pre-ignition would be more accurate but is more than two syllables.

            • > ethanol to boost the Octane ratings.

              Ethanol doesn't contain octane. Ethane with an alcohol group.

              There is always confusion about this. There is a big difference between Octane and Octane rating.

              Octane is a hydrocarbon. https://en.wikipedia.org/wiki/... [wikipedia.org] Octane rating is a measurement of a flammable chemical's resistance to compression ignition. https://en.wikipedia.org/wiki/... [wikipedia.org]

              Ethanol does in fact increase the octane rating of a fuel. If a vehicle is designed to use alcohol or methanol, the result is that the engine can have significantly high compression, as they have a 110 Octane rating.

              And

            • Ethanol doesn't contain octane. Ethane with an alcohol group.

              Octane ratings don't measure octane. They measure combustion compared to iso-octane and n-heptane.

          • Petrol engines love to burn water - that's the reason for water injection in WW2 engines.
            Here in Europe the generally presented narrative is that, by using bio elements in fuel (oil in diesel and ethanol in gasoline) we reduce the quantity of crude oil used, so we reduce the overall CO2 footprint. There's an European (and national) mandate to use bio components in fuels.
            As for the Octane rating, they seemed to do just fine for 20+ years between dropping lead tetraethyl fuel additive in the 1980-1990 and for

        • by suss ( 158993 )

          Last i checked, most of the "Premium" fuel doesn't have ethanol.
          Things like BP Ultimate, Shell V-Power and Total Excellium.
          They cost more, though, but at least they won't slowly dissolve things in older engines.

          • Last i checked, most of the "Premium" fuel doesn't have ethanol. Things like BP Ultimate, Shell V-Power and Total Excellium. They cost more, though, but at least they won't slowly dissolve things in older engines.

            Probably Toluene. I haven't seen the breakdown of those fueld, but Benzene can boost the Octane rating to. A lot of people were really pissed when they took tetraethyl lead out of gasoline as well.

            Meanwhile, the plastic parts issue is to me pretty specious. I have modern cars, and garden engines. They handle Ethanol in fuel just fine. And have for many years, so that's some pretty vintage stuff that ethanol will eat through.

        • In Europe basically you can basically no longer buy fuel without a "bio" component. It is now at a minimum of 5% to 8%, Even the "Super" 99 or 100 octane fuel has ethanol inside.

          And that percent of bio is extremely low for a good reason. In the US we are using 10% ethanol, or rarely 85 percent in gasoline (or I guess 15% gasoline in ethanol). You could never do that much bio in a diesel engine unless you enjoy having problems.
          I remember my diesel Cruze manual saying you could run up to B15 diesel, but you really shouldn't put any biodiesel in it at all.

  • ...missing sock pairs

  • Long before the arrival of the first plow millions of buffalo in the midwest thundered above rich black soil that was alive, and up to six feet thick. The cover plants and micro biome sequestered huge amounts of Carbon. Today, the ability of soil to draw giga tons of CO2 from the atmosphere and sequester it in well tended living soil may be technology to remediate the build up of CO2 from fossil fuel combustion.

  • Importing soil due to the climate that is, from the Sahara. This happens in large quantities every few years, in smaller quantities in every southerly wind.

    https://www.mirror.co.uk/news/... [mirror.co.uk]

    What it means is that it can happen naturally as well (loess soils, see https://en.wikipedia.org/wiki/... [wikipedia.org]). Or at least mostly naturally as far as we know. Meanwhile the Sahara may also be getting soil from elsewhere at times, e.g. Arabia?

  • I am not ignoring an ecological catastrophe in front of me (since I live in the Midwest, it's kinda important to me on a real day to day basis) but the implications elude me. When I read the headline I was wondering "so this lost soil where did it go? the ocean floor?". But if it is simply filling in hollows and flattening the landscape - I'm not clear why this is A Bad Thing. Anyone who has lived in wheat country, or traversed it (I used to travel between Melbourne and Adelaide, Australia regularly and I v
    • In related news, massive dust storms from Africa hit Europe and especially Spain..

      It's bad because this is how the Sahara Desert was created.
  • by TomGreenhaw ( 929233 ) on Thursday March 17, 2022 @04:35AM (#62365651)
    Only two generations ago, our grandparents in the US fought to stop the dust bowl in the 1930's. Common sense government regulation and incentives have been shown to address the issue. How soon we forget and with tragic consequences.
  • No-till farming is only really possible for row crops like corn and soy if you use some sort of pesticide resistant strain. This enables planting without tilling, and then herbicide applications to take care of the weeds normally addressed by tilling them under before planting. What are the odds those concerned with soil losses from the Midwest start pushing GMO as the solution?
  • since Euro-American settlement approximately 160 years ago, agricultural fields in the midwestern U.S. have lost, on average, two millimeters of soil per year.

    Industrial agriculture, where the output is to minimize cost per acre (as opposed to maximize yield per acre as in labor-intensive household agriculture), it is ecologically unsustainable unless some serious countermeasures are implemented.

    Our industrial agricultural sector implements 2-phase crop rotations (say, corn/wheat to soy), but none implement a cover crop phase, let alone a fallow phase with native grass (in which livestock can feed and fertilize-poop on it.) Either fallow or cover crops help ret

    • That's not entirely true, although I'll admit it's probably majority true. In areas where there is still a fair bit of small farming that mixes animal agriculture and row crops, it's pretty common to rotate fields onto an alfalfa/grass mix or oats for extended periods for regeneration (you need the hay and straw anyway). Manure from the livestock that are in feedlots (younger animals going for slaughter) gets spread manually on the fields year round as the pens are cleaned, and in the winter it's still ve

  • The farms of the midwest raise the food that sustains the lifestyles of East and West coast city dwellers that go on online platforms to speak negatively of farms, faming practices, and farmers.
    • by dryeo ( 100693 )

      The opposite is also true, the coastal city dwellers buying the food and paying the taxes for the farming subsidies support the farmers in their lifestyle.

  • We'll only be able to keep farming these areas for another couple of millennia.
  • The study doesn't seem to address this question. It only talks about a measurement and "modeling" which I always raise an eyebrow at whenever a FUD conclusion is drawn.

    • Well, a great deal of it went into the lakes, rivers, and streams, which are still fouled today.

      In a lot of the lakes, if you take a core sample of the bottom, you will see what they call the "settler line". There is a discontinuity of clean sand transitioning to the muddy bottoms we think is normal.

      (Note I don't say 'all lakes' - some lakes have always been muddy)

  • The reason the prairies have such soils is the millennia of grasses that grew, died, and were turned in to soil over time.

    The loss is permanent in many cases. We are living on the banked carbon sequestration of our past, and once it's gone down river, it's not coming back. This includes grain exports.

    (caveat - I used to be on a farming committee in BC, which has much more severe soil loss problems due to mountains)

  • The original prairie grass in the midwest built up topsoil over thousands of years. Farmers stripped that away to plant seasonal crops which leave the ground without cover for most of the year.
    Since 83% of farmland is used to grow animal feed (corn and soy), this could easily be allowed to revert to prairie grass to protect the topsoil and start the regeneration process.

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