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posted by janrinok on Saturday January 21 2023, @07:27PM   Printer-friendly
from the dishing-the-dirt dept.

First precise calculation of the pre-agricultural rate of erosion across the Midwestern U.S., thanks to exploding stars:

In a discovery that has repercussions for everything from domestic agricultural policy to global food security and the plans to mitigate climate change, researchers at the University of Massachusetts recently announced that the rate of soil erosion in the Midwestern US is 10 to 1,000 times greater than pre-agricultural erosion rates. These newly discovered pre-agricultural rates, which reflect the rate at which soils form, are orders of magnitude lower than the upper allowable limit of erosion set by the U.S. Department of Agriculture (USDA).

The study, which appears in the journal Geology, makes use of a rare element, beryllium-10, or 10Be, that occurs when stars in the Milky Way explode and send high-energy particles, called cosmic rays, rocketing toward Earth. When this galactic shrapnel slams into the Earth's crust, it splits oxygen in the soil apart, leaving tiny trace amounts of 10Be, which can be used to precisely determine average erosion rates over the span of thousands to millions of years.

[...] The numbers are not encouraging. "Our median pre-agricultural erosion rate across all the sites we sampled is 0.04 mm per year," says Larsen. Any modern-day erosion rate higher than that number means that soil is disappearing faster than it is accumulating.

Unfortunately, the USDA's current limit for erosion is 1 mm per year—twenty-five times greater than the average rate Larsen's team found. And some sites are experiencing far greater erosion, disappearing at 1,000 times the natural rate. This means that the USDA's current guidelines will inevitably lead to rapid loss of topsoil.

[...] Yet, there's no reason to despair. "There are agricultural practices, such as no-till farming, that we know how to do and we know greatly reduce erosion," says Quarrier. "The key is to reduce our current erosion rates to natural levels," adds Larsen.

Journal Reference:
Caroline L. Quarrier, Jeffrey S. Kwang, Brendon J. Quirk, et al.; Pre-agricultural soil erosion rates in the midwestern United States. Geology 2022;; 51 (1): 44–48. doi: https://doi.org/10.1130/G50667.1


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  • (Score: 4, Insightful) by JoeMerchant on Saturday January 21 2023, @07:40PM (2 children)

    by JoeMerchant (3937) on Saturday January 21 2023, @07:40PM (#1287948)

    There is no reason to believe that farmers small or corporate will follow best soil conservation practices because soil erosion is a problem for future generations, not important to making the next loan payment or quarterly report.

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    • (Score: 4, Insightful) by bobthecimmerian on Saturday January 21 2023, @10:12PM (1 child)

      by bobthecimmerian (6834) on Saturday January 21 2023, @10:12PM (#1287960)

      Most environmentally friendly farming practices are labor-intensive or reduce yield per acre, so there's a strong financial incentive to ignore them.

      • (Score: 4, Insightful) by HiThere on Sunday January 22 2023, @12:18AM

        by HiThere (866) Subscriber Badge on Sunday January 22 2023, @12:18AM (#1287974) Journal

        Not necessarily, but others limit the choice of what crops you can plant. So, yeah, there are strong pressures to ignore the problem.

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  • (Score: 2, Disagree) by Runaway1956 on Saturday January 21 2023, @07:43PM (13 children)

    by Runaway1956 (2926) Subscriber Badge on Saturday January 21 2023, @07:43PM (#1287949) Journal

    Really, everyone needs to rake their leaves up, and burn them. Fallen leaves and other rotting vegetation account for almost all new topsoil. Animal bones and carcasses generally don't last long enough to become part of the soil.

    I think that I read somewhere that it takes 1000 years to create an inch of topsoil. Whatever, I know it takes a lot longer to create an inch of topsoil than it takes to burn off the vegetation!

    • (Score: 5, Interesting) by JoeMerchant on Saturday January 21 2023, @09:25PM (8 children)

      by JoeMerchant (3937) on Saturday January 21 2023, @09:25PM (#1287956)

      In my grandfather's suburban lawn and two of my own, we have observed 5 to 7mm per year of topsoil gain (actual metric: 2-3" per 10 years) which we theorize comes from our lawn care practices which are: mow the grass about 1/2 as frequently as the neighbors and at a significantly higher mower deck height, throwing up considerably less dust than most of our neighbors in the process. Most of that dust quickly resettles somewhere within 2-300' of where it was "launched" and so: our lawns build up while neighbors' lawns sink. It's especially dramatic vs neighbors with "professional" lawn services that power-edge weekly, set the mower deck as low as possible, fertilize and water, etc. etc.

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      • (Score: 4, Interesting) by krishnoid on Saturday January 21 2023, @11:59PM (5 children)

        by krishnoid (1156) on Saturday January 21 2023, @11:59PM (#1287970)

        Some places provide curbside yard waste bins and collection for grass clippings, leaves, smaller branches, etc. Then it's all taken to the giant compost pile in the sky (well, a little bit north of here), and if you drive there you can get free compost and mulch if you shovel it yourself. So that's not bad.

        • (Score: 2) by JoeMerchant on Sunday January 22 2023, @02:26AM (4 children)

          by JoeMerchant (3937) on Sunday January 22 2023, @02:26AM (#1287995)

          Bag your clippings? hahahahahahahahhahahahahahahahahah.... NEVER!

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          • (Score: 2) by krishnoid on Sunday January 22 2023, @02:34AM (3 children)

            by krishnoid (1156) on Sunday January 22 2023, @02:34AM (#1288000)

            If you don't do that, don't you need a thatch rake or something so they don't mat down on the dirt and build up?

            • (Score: 4, Informative) by optotronic on Sunday January 22 2023, @03:02AM (1 child)

              by optotronic (4285) on Sunday January 22 2023, @03:02AM (#1288007)

              Not if you use a mulching mower and mow often enough for the clippings to disappear into the lawn. Typically that means cutting no more than 1/3 off the grass blades. In the spring you may have to mow more often than once a week; in the heat of the summer, maybe once every two weeks. At least that's how it works with cool season grasses in the midwest.

              It should be obvious that mulch mowing is less work than bagging and disposing of clippings, then adding compost to make up for the loss of material.

              If mowing more often than once a week when the grass grows fast is too much for you, note that cutting off more than 1/3 of the grass blades is bad for the lawn.

              Mowing lawns is a lot of work and the best solution is to eliminate the lawn in an environmentally friendly manner. Sadly, I don't think that's allowed in most communities where the rules, presumably unintentionally, hasten the destruction of the environment.

              • (Score: 3, Insightful) by quietus on Tuesday January 24 2023, @01:10PM

                by quietus (6328) on Tuesday January 24 2023, @01:10PM (#1288340) Journal

                There are rules for mowing the lawn where you live? I slowly start to understand the eternal discussions about governmental overreach in the US.

                (Over here (Belgium) there's a movement afoot *not* to mow the lawn anymore apart from a few times a year -- figured that the sum of lawns, wilded, would dwarf the size of the currently existing nature reserves.)

            • (Score: 3, Informative) by JoeMerchant on Sunday January 22 2023, @02:09PM

              by JoeMerchant (3937) on Sunday January 22 2023, @02:09PM (#1288053)

              Similar to optotronics response: mulching mower, and in Florida if you mow before the grass is 6" tall, you're good: St. Augustine, Bahia, whatever, it will decompose and fertilize the lawn.

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      • (Score: 5, Funny) by driverless on Sunday January 22 2023, @06:42AM (1 child)

        by driverless (4770) on Sunday January 22 2023, @06:42AM (#1288025)

        Shit, I've observed 5-7mm of topsoil gain per year in parts of the kids bedrooms and I'm pretty sure it has nothing to do with mowing a lawn.

        • (Score: 2) by JoeMerchant on Sunday January 22 2023, @02:15PM

          by JoeMerchant (3937) on Sunday January 22 2023, @02:15PM (#1288054)

          The stuff that accumulates in and under carpet is not insignificant...

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    • (Score: 4, Informative) by HiThere on Sunday January 22 2023, @12:21AM (3 children)

      by HiThere (866) Subscriber Badge on Sunday January 22 2023, @12:21AM (#1287975) Journal

      There are reasons to burn grass and leaves, but it's not to build topsoil. If you want to build topsoil, compost the stuff, and then put the compost back on the ground.

      --
      Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
      • (Score: 4, Interesting) by deimtee on Sunday January 22 2023, @01:09AM

        by deimtee (3272) on Sunday January 22 2023, @01:09AM (#1287978) Journal

        To be honest, I thought he was being sarcastic.
        We have green waste bins here, but I don't use them. Everything goes in the compost or becomes mulch. I don't rake leaves, the mulching mower gets them along with the grass (deck set high enough that it all drops down into the grass instead of sitting on top.) I also have a little home shredder that turns any prunings into mulch. It can handle up to about 30mm. Anything bigger becomes firewood, and the ash goes in the compost.

        --
        If you cough while drinking cheap red wine it really cleans out your sinuses.
      • (Score: 2, Insightful) by Runaway1956 on Sunday January 22 2023, @02:25AM (1 child)

        by Runaway1956 (2926) Subscriber Badge on Sunday January 22 2023, @02:25AM (#1287994) Journal

        deimtee effectively answered for me. I was being sarcastic. But, I just walked outside a short while ago, and smelled the yummy smells of my garden. See, I've been collecting leaves for mulch. The "new" section of garden has recently been cleared of forest undergrowth, and I ran the tiller over it. Of course, the tiller didn't do especially well, because all of the roots etc. But, I did break up the top 1 to 1 1/2 inches of soil. Now, I'm throwing leaves by the trailerload onto the garden, and running the mulching mower over them. The leaves I'm collecting include this year's fallen leaves, as well as last year's rotten leaves, and maybe some that are even older. Throw a blanket of leaves on the ground 4 to 6 inches deep, run the mower over them, and you're left with about 1/2 inch of nice mulch. Since we don't have very cold winters, decomposition is taking place, right in the middle of winter.

        There's a light rain falling right now, enhancing that rich fertile smell from the garden. Just yummy. And it will be yummier still when I feed that fertilizer to the family!

        Oh. If you're curious, I cleared that undergrowth by pulling the saplings out of the ground, cutting a few sticks of firewood from those that are big enough, then all the brush went into a pile to decompose naturally. I'll probably throw a load of sawdust on top of the pile, to retain moisture and hasten decomposition. No burning, and I didn't even use much gasoline to clear that fresh ground.

        • (Score: 4, Informative) by anubi on Monday January 23 2023, @07:03AM

          by anubi (2828) on Monday January 23 2023, @07:03AM (#1288146) Journal

          I found it helpful to add water soluble nitrogen to the soil. I'm talking nitrates or urea.

          All the little soil buggies and plants need nitrogen to make amino acids, which are used to make proteins.

          Once the nitrogen couples to itself (N2) and wafts off to the atmosphere, it's no longer bioavailable. It will require a thunderstorm (lightning/intense electrostatic fields), legumes, haber-bosch process, a diesel engine, or a gasser run lean, to convert atmospheric nitrogen into something a plant can use.

          I save my pee for my own compost heap. Its mostly urea, the end product of protein metabolism (NH2)2CO. Unless there is something really wrong with you, pee should be sterile. It was so pure it was just in your blood stream before being filtered out.

          The solid we make is not good for tight reinput to our food. A lot of diseases can be spread this way. That stuff is what was offered to the digestive system, yet was not absorbed. There is a reason it wasn't absorbed. That stuff needs to go to other bacteria which can completely disassemble that "crap".

          Nitrogen is a pretty potent accelerant for organic decomposition and fertilizer. Potassium Nitrate is commonly used to accelerate rotting of stumps, by supplying nitrogen to build bug proteins.

          --
          "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
  • (Score: 2, Disagree) by khallow on Sunday January 22 2023, @01:20AM

    by khallow (3766) Subscriber Badge on Sunday January 22 2023, @01:20AM (#1287980) Journal

    The numbers are not encouraging. "Our median pre-agricultural erosion rate across all the sites we sampled is 0.04 mm per year," says Larsen. Any modern-day erosion rate higher than that number means that soil is disappearing faster than it is accumulating.

    The model is broken. If erosion matches soil creation exactly under every condition, then how do you get soil in the first place? For example, about 14k years ago much of their sites would have been under a kilometer of ice. Meaning there might be a great base for soil under that ice, but no actual soil. And at a glance, their model has net soil growth not of 0.04 mm per year, but zero.

    My take is that a better model here for pre-agricultural soil is a logistics model [wikipedia.org] where soil growth starts high when you have thin soil and slows down as soil thickness increases until it reaches the above stable point. My take is that human agriculture has an artificially high level of soil creation due to fertilizer use and the practice of recycling plant material back into the soil.

  • (Score: 4, Interesting) by pdfernhout on Sunday January 22 2023, @01:39AM

    by pdfernhout (5984) on Sunday January 22 2023, @01:39AM (#1287984) Homepage

    https://e360.yale.edu/features/how-the-loss-of-soil-is-sacrificing-americas-natural-heritage [yale.edu]
    "You hear many different numbers regarding that black Iowa soil. It’s often repeated that the topsoil — the nutrient-rich A horizon — was some 14 to 16 inches deep when the prairie was first broken, a fantastic depth of fertility rivaled only by some regions in the Ukraine. By the mid-1970s — roughly a century after the prairie was broken — it was reported that, in places, half of that topsoil had already been lost to erosion from wind and runoff. There was a lot of talk about soil conservation, of course — about contour plowing and set-aside programs that paid farmers to keep marginal land out of cultivation. Yet year by year, the soil loss went on. ... The number [scientists in a new study using satellite imagery] arrived at is shocking. “We predict,” they wrote, “[that] the A-horizon has been completely removed from 35±11% of the cultivated area of the Corn Belt.” Plus or minus 11 percent is a large range of uncertainty. But its meaning is plain. At best, 24 percent of the topsoil in the Corn Belt has been completely removed by farming. At worst, 46 percent has been lost."

    I had read somewhere (Wes Jackson?) that big parts of the Midwest had gone from six feet of topsoil before farming and were now six inches, but perhaps that is an exaggeration compared to the above?

    How to rebuild fertile topsoil by grinding up rock:
    https://www.remineralize.org/ [remineralize.org]
    "Remineralization utilizes finely ground rock dust and sea-based minerals to restore soils and forests, produce higher yields and more nutritious food, and store carbon in soils to stabilize the climate."

    --
    The biggest challenge of the 21st century: the irony of technologies of abundance used by scarcity-minded people.
  • (Score: 2, Insightful) by legont on Sunday January 22 2023, @03:52AM (6 children)

    by legont (4179) on Sunday January 22 2023, @03:52AM (#1288012)

    Bill Gates is the biggest owner of agricultural lands in the US. He is a famous tree hugger too. How is erosion on his lands?

    --
    "Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
    • (Score: 3, Insightful) by JoeMerchant on Sunday January 22 2023, @05:12PM (5 children)

      by JoeMerchant (3937) on Sunday January 22 2023, @05:12PM (#1288064)

      The thing about being the biggest crop land owner is: if you don't follow industry typical practices you won't be the biggest crop land owner for long.

      Economic pressure is real, ownership doesn't make one immune.

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      • (Score: 1) by khallow on Monday January 23 2023, @02:34AM (4 children)

        by khallow (3766) Subscriber Badge on Monday January 23 2023, @02:34AM (#1288123) Journal

        Economic pressure is real, ownership doesn't make one immune.

        Economic pressure depends on your net costs. For example, if I take farmland I own and just leave it fallow, the only costs I have are taxes and opportunity costs. If I use a slightly less cost effective method, I'm operating at a small loss compared to the norm. Someone like Gates, who starts with a lot of assets, can afford a lot of this sort of economic pressure for a long time. Sure, without something providing replacement cash flow (that is, opposite economic pressure) he could eventually run out, but I think it'd be at least decades and that's assuming he doesn't have cash flow to keep going.

        Now, if he were shorting Bitcoin or Microsoft, that could generate a lot more economic pressure in the short term since the potential forced-play liabilities can swamp even Gates's level of assets.

        • (Score: 2) by JoeMerchant on Monday January 23 2023, @02:51AM (3 children)

          by JoeMerchant (3937) on Monday January 23 2023, @02:51AM (#1288128)

          >Someone like Gates, who starts with a lot of assets, can afford a lot of this sort of economic pressure for a long time.

          Depends on how leveraged those investments are, and how many other, different things Melinda wants to do in the meantime.

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          • (Score: 1) by khallow on Monday January 23 2023, @07:01AM (2 children)

            by khallow (3766) Subscriber Badge on Monday January 23 2023, @07:01AM (#1288145) Journal

            Depends on how leveraged those investments are

            Indeed. I can't read minds or accounting books from this far away, but it strikes me that if Gates is snapping up farmland for some tree hugging reason, it's probably not going to make sense to borrow a lot of money for it. Long term goals do terribly when they're highly leveraged.

            Further, I'm reading that he owns merely 240k acres [theguardian.com] of farmland. If that genuinely makes him the owner of the most privately owned farmland, then nobody really is trying - since there is over 900 million acres [usda.gov] of farmland in the US!

            • (Score: 2) by JoeMerchant on Monday January 23 2023, @10:58AM (1 child)

              by JoeMerchant (3937) on Monday January 23 2023, @10:58AM (#1288155)

              You go ahead and live the idealized Billionaire's fantasy out in your mind. The very wealthy people I have known are mostly leveraged in their investments, perhaps not to risky levels, but enough to not allow them to let income producing property stand idle.

              But, yeah, 240,000 acres probably isn't even $1B, in investment, he _could_ do whatever he wants with that, but it's a tiny slice of what is out there.

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              • (Score: 1) by khallow on Monday January 23 2023, @03:22PM

                by khallow (3766) Subscriber Badge on Monday January 23 2023, @03:22PM (#1288181) Journal

                The very wealthy people I have known are mostly leveraged in their investments

                Would that include Bill? Because otherwise, you don't have relevant knowledge here.

                But, yeah, 240,000 acres probably isn't even $1B, in investment, he _could_ do whatever he wants with that, but it's a tiny slice of what is out there.

                My linked story confirms that (the land was valued at $690 million at the time of the story). My suspicion is that we'll find that something like ADM (Archer Daniels Midland Co), a huge agricultural products firm are probably the number one owner of private agricultural land, and even they probably don't hold a candle to federal owned land.

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