tag:theconversation.com,2011:/au/topics/soil-science-30866/articlessoil science – The Conversation2024-01-29T05:26:27Ztag:theconversation.com,2011:article/2166402024-01-29T05:26:27Z2024-01-29T05:26:27ZAustralia’s soils are notoriously poor. Here’s how scientists are working to improve them<p>Most things you eat grew in soil or ate plants growing in soil. We don’t think much about it, but soil is essential to life. </p>
<p>During the last Ice Age, much of the northern hemisphere was covered in glaciers. As they moved, glaciers eroded away the top layer of rock and left a fresh layer of rock, ready to weather into soil. </p>
<p>But Australia didn’t have this renewal of soil from grinding ice – or from volcanoes, which dredge up minerals vital to plant life from deep below. As a result, our soils are famously very poor – heavily weathered, old, and short on nutrients. This is one reason why we have so much land devoted to grazing animals (crops need more nutrients than grass does), a heavy reliance on fertilisers and a <a href="https://www.soilscienceaustralia.org.au/about/about-soil/state-soils/">detailed knowledge</a> of fertile soils where they exist. </p>
<p>Unfortunately, our soils – <a href="https://link.springer.com/chapter/10.1007/978-3-319-43394-3_20">valued at A$930 billion</a> – are under threat. The latest <a href="https://soe.dcceew.gov.au/land/environment/soil">State of the Environment report</a> rated the health of our soils as “poor” and declining. Late last year, the government <a href="https://www.agriculture.gov.au/agriculture-land/farm-food-drought/natural-resources/soils/national-soil-action-plan">released a national plan</a> to improve our soils. </p>
<p>Researchers are working on ways of improving Australian soils to make agriculture more sustainable and less reliant on fertilisers. Here are some examples. </p>
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<a href="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black soil in hands" src="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Good soil is hard to come by.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>From farm to food</h2>
<p>You might wonder what the problem is. Aren’t we growing and exporting more food than ever? Farm productivity and incomes are at <a href="https://www.agriculture.gov.au/abares/products/insights/snapshot-of-australian-agriculture#farm-incomes-at-record-highs">record highs</a> and many farmers are adopting more efficient practices informed by research to help manage their soil amid new risks such as shifting rainfall and <a href="https://theconversation.com/what-is-a-flash-drought-an-earth-scientist-explains-194141">flash droughts</a>. </p>
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<p>But many of our soils are fundamentally vulnerable because they function in old and weathered landscapes. To keep the food coming, farmers have had to resort to clearing more land and increasing <a href="https://soe.dcceew.gov.au/land/environment/soil#soil-health">fertilisers, pesticides and herbicides</a>. That works short term. But there are <a href="https://theconversation.com/intensive-farming-is-eating-up-the-australian-continent-but-theres-another-way-130877">increasing concerns</a> this intensive approach ends up making soil worse – more eroded, more saline and more acidic. All three of these are worsened by our changing climate.</p>
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Read more:
<a href="https://theconversation.com/regenerative-agriculture-is-all-the-rage-but-its-not-going-to-fix-our-food-system-203922">'Regenerative agriculture' is all the rage – but it's not going to fix our food system</a>
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<h2>What can be done?</h2>
<p>Soil scientists have long worked on ways to get more out of our soils. The Green Revolution of the 1960s led to huge increases in yield – but required huge increases in application of fertilisers and other chemicals. </p>
<p>In Australia, farmers will likely have to rely on fertiliser for the foreseeable future as a way to correct soils which are naturally short on nutrients. </p>
<p>What we can do is learn to apply fertiliser only when it’s needed. That’s good for farmers – fertiliser is expensive – and good for the health of soil and nearby waterways. </p>
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Read more:
<a href="https://theconversation.com/what-sub-sahara-can-learn-from-indias-green-revolution-the-good-and-the-bad-78868">What sub-Sahara can learn from India's 'Green revolution': the good and the bad</a>
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<p>In southwest Western Australia, for example, soil scientists are <a href="https://soilswest.org.au/project-npk/">working to understand</a> how best to dose the soil with nitrogen, potassium and phosphorus – and how much to use. </p>
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<p>In <a href="https://estuaries.dwer.wa.gov.au/soil-wise">another project</a>, scientists are working with farmers and land managers to sample and test their soil and interpret the data together. The goal is to pare back fertiliser use, which improves water quality in nearby waterways and estuaries, as unused fertiliser runs off and can trigger algal blooms. </p>
<p>Precision application of fertiliser is one method. But there are many other innovative soil projects across Australia. </p>
<p>For instance, fungi do vital work in cycling soil nutrients. And mycorrhizal fungi go one step further and live in symbiotic relationships with plants. What if we could use these fungi as a kind of living biofertiliser for grain crops? Scientists <a href="https://groundcover.grdc.com.au/agronomy/soil-and-nutrition/biofertiliser-potential-in-native-fungus">are exploring</a> the potential for one such species, the ridge-stemmed bolete (<em>Austroboletus occidentalis</em>), to play this role. </p>
<h2>It’s alive!</h2>
<p>Researchers recently estimated <a href="https://doi.org/10.1073/pnas.2304663120">soil contains</a> about three-fifths of all species on the planet, including bacteria, fungi, viruses, nematodes, mites, worms and insects.</p>
<p>Soil is, in short, teeming with life. Some underground lifeforms are pests to farmers, chewing on the roots of crops. But many others are beneficial. </p>
<p>If we <a href="https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(23)00211-2">improve our understanding</a> and measurement of soil microorganisms, we could use them to speed up recovery of degraded landscapes, such as former mine sites or unproductive farmland. </p>
<p>Our understanding of how things living in soil impact environments and respond to change is rapidly growing, but we are still scratching the surface. For example, more than 90% of the estimated 5 million species of fungi are <a href="https://www.theguardian.com/environment/2023/aug/30/flora-fauna-and-funga-un-backs-new-term-for-conservation-discussions">currently unknown</a>.</p>
<h2>Digging deeper</h2>
<p>Australia has the <a href="https://doi.org/10.1073/pnas.1706103114">world’s third highest loss</a> of soil carbon over the last 250 years, caused largely by very high rates of land clearing. We risk releasing even more soil carbon in the future, as climate change is expected to worsen erosion and bushfire intensity. </p>
<p>One response by the government has been to create a market for soil carbon credits, the first of which went on sale last year. The market-based approach has been <a href="https://doi.org/10.1016/j.jenvman.2023.119146">widely criticised</a>. Soil experts <a href="https://theconversation.com/heres-how-to-fix-australias-approach-to-soil-carbon-credits-so-they-really-count-towards-our-climate-goals-210880">have called</a> for the credit system to be much more robust to ensure it actually works.</p>
<p>Research into the problems facing our soil is important, but we’ll need government and industry backing to better coordinate the response. </p>
<p>That’s why last year’s action plan has been broadly welcomed, despite being 18 months overdue. The joint federal-state plan indicates governments at both levels recognise the danger to our soil. Framed around securing soil as a “national asset”, the plan envisages standardising soil data collection and sharing, accelerating uptake of best-practice soil management, among other things. </p>
<p>Will it stop the damage done to our lifegiving soils? That remains to be seen. </p>
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Read more:
<a href="https://theconversation.com/heres-how-to-fix-australias-approach-to-soil-carbon-credits-so-they-really-count-towards-our-climate-goals-210880">Here's how to fix Australia's approach to soil carbon credits so they really count towards our climate goals</a>
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<p class="fine-print"><em><span>Ryan Borrett is part of SoilsWest and collaborates on projects that receive funding from Murdoch University, the Western Australian Department of Primary Industries and Regional Development, and the Grains Research and Development Corporation. </span></em></p>The health of our soils is poor – and getting worse. Here’s why that matters and what we can do about itRyan Borrett, Science Communications Coordinator, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1731622021-12-05T07:18:57Z2021-12-05T07:18:57ZSoil isn’t dirt: it’s the foundation of life and needs real care<figure><img src="https://images.theconversation.com/files/435542/original/file-20211203-27-1fw2c5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>Healthy soil is critical for life on earth. It can contribute to climate change mitigation and adaptation, food and nutrition security. It is central to achieving sustainable development goals. It is the foundation of life on land. It provides many ecosystem services and helps achieve ecosystem restoration. </p>
<p>The biggest challenge when it comes to soil is getting people to stop treating soil like dirt and start treating it with the respect it deserves. And this comes from soil stewardship, really caring for the land. But to do that, it’s important to understand the soil ecosystem that needs restoring. </p>
<p><a href="https://theconversation.com/lessons-from-kenya-on-how-to-restore-degraded-land-98178">Land degradation</a> is a serious problem when it comes to soil. Degraded landscapes are more vulnerable to the stresses of droughts, floods and erratic rainfall. Education about good soil practices is key, and people like farmers who use the soil need the tools to practise good soil management. </p>
<p>In today’s episode of Pasha, Leigh Ann Winowiecki, a soil systems scientist at the World Agroforestry, and Rattan Lal, a distinguished professor of soil science at Ohio State University, discuss why soil needs to be front and centre of global policies.</p>
<p>We’ve also collected some more articles about soil <a href="https://theconversation.com/africa/search?q=%23WorldSoilDay2021&sort=recency&language=en&date=all&date_from=&date_to=">here</a>.</p>
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<p><strong>Photo:</strong>
“Arid landscape in north Senegal. Eroded soil with few acacia trees. Traces of erosion on the sandy ground. Dry climate conducting to the desertification. Natural picture taken during the dry season.” By Boulenger Xavier <a href="https://www.shutterstock.com/image-photo/arid-landscape-north-senegal-eroded-soil-1020803248">Shutterstock</a></p>
<p><strong>Music</strong>
“Happy African Village” by John Bartmann, found on <a href="http://freemusicarchive.org/music/John_Bartmann/Public_Domain_Soundtrack_Music_Album_One/happy-african-village">FreeMusicArchive.org</a> licensed under <a href="https://creativecommons.org/publicdomain/zero/1.0/">CC0 1</a>.</p>
<p>“minimal ambient music/atmosphere fragment” by Clacksberg found on <a href="https://freesound.org/people/Clacksberg/sounds/495747/">Freesound</a> licensed under <a href="http://creativecommons.org/publicdomain/zero/1.0/">Creative Commons</a></p><img src="https://counter.theconversation.com/content/173162/count.gif" alt="The Conversation" width="1" height="1" />
The global community must understand the importance of soil in order to protect it.Ozayr Patel, Digital EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1700132021-11-10T19:07:26Z2021-11-10T19:07:26ZThe Moon’s top layer alone has enough oxygen to sustain 8 billion people for 100,000 years<figure><img src="https://images.theconversation.com/files/430933/original/file-20211108-15-r4l59u.png?ixlib=rb-1.1.0&rect=0%2C18%2C1100%2C1080&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">NASA/JPL</span></span></figcaption></figure><p>Alongside advances in space exploration, we’ve recently seen much time and money invested into technologies that could allow effective <a href="https://www.nasa.gov/isru/">space resource utilisation</a>. And at the forefront of these efforts has been a laser-sharp focus on finding <a href="https://www.sciencedirect.com/science/article/pii/S0032063319301266">the best way to produce oxygen</a> on the Moon.</p>
<p>In October, the Australian Space Agency and NASA <a href="https://www.nasa.gov/feature/nasa-australia-sign-agreement-to-add-rover-to-future-moon-mission">signed a deal</a> to send an Australian-made rover to the Moon under the Artemis program, with a goal to collect lunar rocks that could ultimately provide breathable oxygen on the Moon. </p>
<p>Although the Moon does have an atmosphere, it’s very thin and composed mostly of hydrogen, neon and argon. It’s not the sort of gaseous mixture that could sustain oxygen-dependent mammals such as humans. </p>
<p>That said, there is actually plenty of oxygen on the Moon. It just isn’t in a gaseous form. Instead it’s trapped inside regolith — the layer of rock and fine dust that covers the Moon’s surface. If we could extract oxygen from regolith, would it be enough to support human life on the Moon?</p>
<h2>The breadth of oxygen</h2>
<p>Oxygen can be found in many of the minerals in the ground around us. And the Moon is mostly made of the same rocks you’ll find on Earth (although with a slightly greater amount of material that came from meteors).</p>
<p>Minerals such as silica, aluminium, and iron and magnesium oxides dominate the Moon’s landscape. All of these minerals contain oxygen, but not in a form our lungs can access.</p>
<p>On the Moon these minerals exist in a few different forms including hard rock, dust, gravel and stones covering the surface. This material has resulted from the impacts of meteorites crashing into the lunar surface over countless millennia.</p>
<p>Some people call the Moon’s surface layer lunar “soil”, but as a soil scientist I’m hesitant to use this term. Soil as we know it is pretty magical stuff that only occurs on Earth. It has been created by a vast array of organisms working on the soil’s parent material — regolith, derived from hard rock — over millions of years. </p>
<p>The result is a matrix of minerals which were not present in the original rocks. Earth’s soil is imbued with remarkable physical, chemical and biological characteristics. Meanwhile, the materials on the Moon’s surface is basically regolith in its original, untouched form.</p>
<h2>One substance goes in, two come out</h2>
<p>The Moon’s regolith is <a href="https://www.lpi.usra.edu/publications/books/lunar_stratigraphy/">made up of</a> approximately <a href="https://sites.wustl.edu/meteoritesite/items/the-chemical-composition-of-lunar-soil/">45% oxygen</a>. But that oxygen is tightly bound into the minerals mentioned above. In order to break apart those strong bonds, we need to put in energy. </p>
<p>You might be familiar with this if you know about electrolysis. On Earth this process is commonly used in manufacturing, such as to produce aluminium. An electrical current is passed through a liquid form of aluminium oxide (commonly called alumina) via electrodes, to separate the aluminium from the oxygen.</p>
<p>In this case, the oxygen is produced as a byproduct. On the Moon, the oxygen would be the main product and the aluminium (or other metal) extracted would be a potentially useful byproduct. </p>
<p>It’s a pretty straightforward process, but there is a catch: it’s very energy hungry. To be sustainable, it would need to be supported by solar energy or other energy sources available on the Moon. </p>
<p>Extracting oxygen from regolith would also require substantial industrial equipment. We’d need to first convert solid metal oxide into liquid form, either by applying heat, or heat combined with solvents or electrolytes. We <a href="https://phys.org/news/2019-10-oxygen-metal-lunar-regolith.html">have the technology</a> to do this on Earth, but moving this apparatus to the Moon – and generating enough energy to run it – will be a mighty challenge.</p>
<p>Earlier this year, Belgium-based startup Space Applications Services announced it was building three experimental reactors to improve the process of making oxygen via electrolysis. They expect to send the technology to the Moon by 2025 as part of the European Space Agency’s in-situ resource utilisation (ISRU) <a href="https://exploration.esa.int/web/moon/-/60127-in-situ-resource-utilisation-demonstration-mission">mission</a>.</p>
<h2>How much oxygen could the Moon provide?</h2>
<p>That said, when we do manage to pull it off, how much oxygen might the Moon actually deliver? Well, quite a lot as it turns out. </p>
<p>If we ignore oxygen tied up in the Moon’s deeper hard rock material — and just consider regolith which is easily accessible on the surface — we can come up with some estimates. </p>
<p>Each cubic metre of lunar regolith contains 1.4 tonnes of minerals on average, including about 630 kilograms of oxygen. NASA says humans need to breathe about <a href="https://www.nasa.gov/pdf/166504main_Survival.pdf">800 grams</a> of oxygen a day to survive. So 630kg oxygen would keep a person alive for about two years (or just over).</p>
<p>Now let’s assume the average depth of regolith on the Moon is <a href="https://www.lpi.usra.edu/publications/books/lunar_stratigraphy/">about ten metres</a>, and that we can extract all of the oxygen from this. That means the top ten metres of the Moon’s surface would provide enough oxygen to support all eight billion people on Earth for somewhere around 100,000 years. </p>
<p>This would also depend on how effectively we managed to extract and use the oxygen. Regardless, this figure is pretty amazing! </p>
<p>Having said that, we do have it pretty good here on Earth. And we should do everything we can to protect the blue planet — and its soil in particular — which continues to support all terrestrial life without us even trying.</p><img src="https://counter.theconversation.com/content/170013/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Grant is affiliated with the human race and as such he has a vested interest in maintaining their ongoing existence. He, therefore, tends to advocate for planet earth, the natural home of the human race. He also has strong feelings for soil which plays a critical role in earth's ecosystems and which has nurtured the emotional, physical, and spiritual health of human beings since their first beginnings.</span></em></p>The next big frontier in space exploration is finding ways to effectively harness oxygen contained within Moon dust. What will it take?John Grant, Lecturer in Soil Science, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1647482021-07-22T14:24:36Z2021-07-22T14:24:36Z‘Cyborg soil’ reveals the secret microbial metropolis beneath our feet<figure><img src="https://images.theconversation.com/files/412425/original/file-20210721-21-1dpqxqn.jpeg?ixlib=rb-1.1.0&rect=22%2C7%2C4974%2C3318&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/white-mold-on-soil-seedlings-flower-1526486159">8H/Shutterstock</a></span></figcaption></figure><p>Dig a teaspoon into your nearest clump of soil, and what you’ll emerge with will contain <a href="https://www.theatlantic.com/health/archive/2013/06/healthy-soil-microbes-healthy-people/276710/">more microorganisms</a> than there are people on Earth. We know this from <a href="https://pubmed.ncbi.nlm.nih.gov/15234515/">lab studies</a> that analyse samples of earth scooped from the microbial wild to determine which forms of microscopic life exist in the world beneath our feet.</p>
<p>The problem is, such studies can’t actually tell us how this subterranean kingdom of fungi, flagellates and amoebae operates in the ground. Because they entail the removal of soil from its environment, these studies destroy the delicate structures of mud, water and air in which the soil microbes reside.</p>
<p>This prompted my lab to develop a way to spy on these underground workers, who are indispensable in their role as <a href="https://www.nationalgeographic.org/encyclopedia/decomposers/">organic matter recycling agents</a>, without disturbing their micro-habitats. </p>
<p><a href="https://www.nature.com/articles/s42003-021-02379-5">Our study</a> revealed the dark, dank cities in which soil microbes reside. We found labyrinths of tiny highways, skyscrapers, bridges and rivers which are navigated by microorganisms to find food, or to avoid becoming someone’s next meal. This new window into what’s happening underground could help us better appreciate and preserve Earth’s <a href="https://www.nationalgeographic.com/science/article/ipbes-land-degradation-environmental-damage-report-spd">increasingly damaged</a> soils. </p>
<h2>Cyborg soil</h2>
<p>In our study, we developed a new kind of “cyborg soil”, which is half natural and half artificial. It consists of microengineered chips that we either buried in the wild, or surrounded with soil in the lab for enough time for the microbial cities to emerge within the mud. </p>
<p>The chips literally act like windows to the underground. A transparent patch in the otherwise opaque soil, the chip is cut to mimic the pore structures of actual soil, which are often strange and counter-intuitive at the scale that microbes experience them. </p>
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<a href="https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Soil on a chip in the lab" src="https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412412/original/file-20210721-15-129lxd9.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Cyborg soil in action in the lab.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<p>Different physical laws become dominant at the micro scale compared to what we’re acquainted to in our macro world. Water clings to surfaces, and resting bacteria get pushed around by the movement of water molecules. Air bubbles form <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC92904/">insurmountable barriers</a> for many microorganisms, due to the surface tension of the water around them.</p>
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<p>Once we’d implanted our chips into the soil, we could watch as microbes filed through on their decomposition commutes, revealing their interactions, their food webs, and how different microbes engineer their surrounding, ever-changing micro-habitats.</p>
<h2>Fungal highways</h2>
<p>When we excavated our first chips, we were met with the full variety of single-celled organisms, <a href="https://www.britannica.com/animal/nematode">nematodes</a>, tiny <a href="https://www.britannica.com/animal/arthropod">arthropods</a> and species of bacteria that exist in our soils. <a href="https://theconversation.com/the-secret-life-of-fungi-how-they-use-ingenious-strategies-to-forage-underground-156610">Fungal hyphae</a>, which burrow like plant roots underground, had <a href="https://cdn.theconversation.com/static_files/files/1723/GIF_3_1M2_1_expt2.gif?1626864445">quickly grown</a> into the depths of our cyborg soil pores, creating a direct living connection between the real soil and our chips.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four panels showing different soil microorganisms" src="https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=145&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=145&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=145&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=183&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=183&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412415/original/file-20210721-19-h5ckaj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=183&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Visitors in our cyborg soil, from left: mud particles, fungal hyphae, a nematode and a microanthropod.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This meant we could study a phenomenon known only from lab studies: the “<a href="https://www.sciencedirect.com/science/article/abs/pii/S0038071710004657">fungal highways</a>” along which bacteria “<a href="https://blogs.scientificamerican.com/artful-amoeba/life-is-a-highway-watch-bacteria-riding-the-fungal-expressway-video/">hitchhike</a>” to disperse through soil. Bacteria usually <a href="https://www.nature.com/articles/ismej201723/">disperse through water</a>, so by making some of our chips air-filled we could watch how bacteria <a href="https://www.youtube.com/watch?v=GXQM0vdrMOU&ab_channel=EdithHammer">smuggle themselves</a> into new pores by following the groping arms of fungal hyphae.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/AnsYh6511Ic?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Unexpectedly, we also found a high number of <a href="https://www.britannica.com/science/protist">protists</a> – enigmatic single-celled organisms which are neither animal, plant or fungus – in the spaces around hyphae. Clearly they too hitch a ride on the fungal highway – a so-far completely unexplored phenomenon.</p>
<p>Because we investigated several hundred possible paths within our cyborg soil chips, including several thousand individual pore spaces, we could also quantify that this was happening often. This shows that hyphae must be an important vector for the dispersal of a large variety of swimming microorganisms, giving them an important advantage when foraging for food in subterranean micro-cities.</p>
<h2>Underground engineering</h2>
<p>In our study, we also wanted to explore how and by what means microbial cities are engineered. One way we could do this was by watching how soil minerals found their way into our chips, creating pockets of real soil space within the artificial structures we’d placed in the ground. </p>
<p>As our chips started to dry, we witnessed how water is sucked through soil pores: a tsunami of water movements that soil microorganisms are regularly exposed to as rain and shine tampers with their tiny worlds. The resulting patterns in the soil minerals looked just like a riverbed system in our macro world.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FlY-MFsrACs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>And it’s not just physical forces that shape the habitat of soil microbes. With their strong hyphal tips, fungi often act like “<a href="https://link.springer.com/article/10.1007/s11104-010-0361-y">ecosystem engineers</a>”, opening up passages and blocking others with their cells. They’re responsible for many of the streets, avenues and bridges in the microbial metropolis.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-secret-life-of-fungi-how-they-use-ingenious-strategies-to-forage-underground-156610">The secret life of fungi: how they use ingenious strategies to forage underground</a>
</strong>
</em>
</p>
<hr>
<p>More surprisingly, we found that other, less “strong” organisms also alter the microscopic structure of soils. A <a href="https://www.britannica.com/science/ciliate">ciliate</a>, for example, which possesses small hair-like extensions for locomotion, can also bulldoze soil with its vigorous foraging for food.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1geXHxe9gBY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Soil, science and society</h2>
<p>Our cyborg soil study ultimately helps connect field ecology with controlled lab studies. It combines the advantages of studying realistic, complex communities of soil organisms while at the same time carefully controlling and adjusting factors like nutrient supply or temperature so that we can see how soils and their microbes react to changes above ground.</p>
<p>But there’s another benefit. We believe that observing the hidden world of soils and their intriguing inhabitants could help people engage emotionally with this vital ecosystem. Other ecosystems have long had <a href="https://www.nature.com/articles/nature.2013.14396">charismatic animals</a> to represent conservation initiatives. Soils on the other hand are still <a href="https://theconversation.com/treated-like-dirt-urban-soil-is-often-overlooked-as-a-resource-158571">associated with dirt</a> and dirtiness. Yet soils support <a href="http://www.fao.org/documents/card/en/c/c6814873-efc3-41db-b7d3-2081a10ede50/">95% of our food production</a>. They store <a href="https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/1051-0761%282000%29010%5B0423%3ATVDOSO%5D2.0.CO%3B2">more than twice</a> the amount of carbon than the biosphere and atmosphere combined.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/treated-like-dirt-urban-soil-is-often-overlooked-as-a-resource-158571">Treated like dirt: urban soil is often overlooked as a resource</a>
</strong>
</em>
</p>
<hr>
<p>We want to show that when you dig your teaspoon into the earth, you’re excavating the upper reaches of an exciting secret metropolis that contains <a href="https://ec.europa.eu/environment/archives/soil/pdf/soil_biodiversity_brochure_en.pdf">a quarter</a> of Earth’s species. The cute organisms in your spoon aren’t dirty: they’re quietly providing vital ecosystem services which support all life above ground. These soil-city dwellers are <a href="https://www.theguardian.com/environment/2021/apr/16/poor-mans-rainforest-stop-treating-soil-like-dirt-aoe">in urgent need</a> of better protection.</p><img src="https://counter.theconversation.com/content/164748/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edith Hammer receives funding from the Swedish Science Foundation, the Swedish Foundation for Strategic Research, and BECC. </span></em></p>There are more microorganisms in a teaspoon of soil than there are humans on Earth – but what are they all up to?Edith Hammer, Associate Lecturer, Department of Biology, Lund UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1607042021-05-12T08:20:44Z2021-05-12T08:20:44ZPay dirt: $200 million plan for Australia’s degraded soil is a crucial turning point<figure><img src="https://images.theconversation.com/files/400212/original/file-20210512-18-61b5qy.jpg?ixlib=rb-1.1.0&rect=28%2C0%2C4665%2C3103&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The food we eat, the clothes we wear, the air we breathe, the water we drink – it’s all underpinned by healthy and productive soils. Since Europeans arrived in Australia, the continent’s soil has steadily been degraded. Yet, until now, we’ve lacked an integrated national approach to managing this valuable and finite resource.</p>
<p>That changed in last night’s federal budget, when Treasurer Josh Frydenberg announced almost A$200 million for a <a href="https://www.awe.gov.au/sites/default/files/2021-05/national-soil-strategy-factsheet.pdf">National Soils Strategy</a>. The 20-year plan recognises the vital role of soils for environmental and human health, the economy, food security, biodiversity and climate resilience.</p>
<p>Our soils face a range of threats, including the loss of prime agricultural land, erosion, acidification, salt accumulation, contamination and carbon loss. Climate change also puts pressure on our soils through through droughts, storms, bushfires and floods.</p>
<p>We contributed expertise as the soil policy was being developed, and believe the final strategy represents a long-needed turning point for this crucial natural asset.</p>
<figure class="align-center ">
<img alt="farm in dust storm" src="https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=370&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=370&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=370&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=465&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=465&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400214/original/file-20210512-17-1vmsho7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=465&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Australia’s soils have been degrading since European settlement.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Why soil matters</h2>
<p>Soil contains organic matter, minerals, gases, water and living organisms. It is slow to form – the average rate of soil production globally is <a href="https://www.sciencedirect.com/science/article/pii/S0016706113003601">around 114 millimetres per 1,000 years</a> – and is considered a non-renewable resource.</p>
<p>Soil underpins a myriad of economic activities. In Australia, it <a href="https://www.soilscienceaustralia.org.au/about/save-our-soils/sos-value-of-australias-soils/2">directly contributes about</a> A$63 billion each year to the economy through agriculture production alone.</p>
<p>Healthy soil is necessary for:</p>
<ul>
<li><p>food and fibre production </p></li>
<li><p>filtering water and retaining sediment to ensure healthy landscapes</p></li>
<li><p>maintaining air quality by preventing dust storms</p></li>
<li><p>carbon storage to help mitigate climate change</p></li>
<li><p>environmental functions such as plant growth </p></li>
<li><p>human nutrition (soil provides nutrients to plants and animals which are transferred to humans once consumed)</p></li>
<li><p>many drugs and vaccines upon which humans rely, such as penicillin</p></li>
<li><p>safe infrastructure (acid sulfate soils and salinity can damage structures such as housing, bridges and roads)</p></li>
<li><p>resilience to natural disasters such as storms, bushfires, floods and droughts. </p></li>
</ul>
<p>However, land degradation, climate change and poor management practices threaten our soil resources.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/even-after-the-rains-australias-environment-scores-a-3-out-of-10-these-regions-are-struggling-the-most-157590">Even after the rains, Australia's environment scores a 3 out of 10. These regions are struggling the most</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="An overly saline mustard field" src="https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400217/original/file-20210512-19-1mtlki0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Soil salinity can ruin crops.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What lies beneath?</h2>
<p>Until now, Australia has lacked a nationally consistent approach to monitor soil health, nor a readily accessible means of storing that data. That means at a national level, our understanding of soil condition, and how it’s changed, has been limited.</p>
<p>Soil monitoring has largely been conducted through various regional, state and federal programs. These often operate in isolation and have differing aims and objectives. And overall investment has not been large or quick enough to create broad improvements in soil health.</p>
<p>In comparison, well-established standardised national systems exist to monitor <a href="https://www.tern.org.au/">terrestrial ecosystems</a>, <a href="http://www.bom.gov.au/?ref=logo">weather, climate and water</a>. These allow an assessment of longer trends and changes to baseline conditions.</p>
<p>The need for a national soil assessment was recognised as far back <a href="https://theconversation.com/search/result?sg=3cba8a33-10bb-4731-b739-16817b5937c1&sp=1&sr=4&url=%2Fa-more-sustainable-australia-we-need-to-talk-about-our-soils-16555">as 2008</a>. And there have long been <a href="https://publications.csiro.au/rpr/download?pid=procite:6de96f40-58f0-4ddf-88de-fe874629fa1d&dsid=DS1">calls for</a> long-term monitoring, consistent information and baseline data collection. </p>
<figure class="align-center ">
<img alt="hand holding dirt" src="https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400218/original/file-20210512-16-1871aho.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The funding will help farmers monitor the health of their soil.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Change from the ground up</h2>
<p>Importantly, the strategy takes a long term view of sustainable soil management. It also considers soil beyond its traditional role in agricultural production and explicitly identifies criteria to measure progress.</p>
<p>The strategy has three arms:</p>
<p><strong>1. Prioritise soil health</strong></p>
<p>This goal takes a “soils first” approach in that sustainable soil management is the primary consideration in policy development and management strategies. This recognises how environmental and agricultural problems can start with poor soil management and create further challenges. For example, soil acidification can lead to <a href="https://publications.csiro.au/rpr/download?pid=csiro:EP177962&dsid=DS3">declines in terrestrial biodiversity</a>, and soil constraints must be addressed first to arrest this. </p>
<p><strong>2. Empower soil stewards and innovation</strong></p>
<p>This approach gives incentives to farmers and other land managers, such as rebates for sampling to determine the soil carbon levels. Carbon is an important measure of soil condition. Gathering such information will help land managers arrest the decline in soil condition, enhancing productivity and soil health.</p>
<p><strong>3. Secure soil science</strong></p>
<p>This approach aims to increase soil knowledge through standardised data collection, management and storage. It will allow for more informed decisions using reliable, up-to-date, accessible information. </p>
<p>Part of this aim involves strengthening training and accreditation programs, and integrating soils into the national school curriculum. This will help create a new generation of soil experts to replace the current crop which is trending to retirement.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-more-carbon-in-our-soil-to-help-australian-farmers-through-the-drought-102991">We need more carbon in our soil to help Australian farmers through the drought</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="young woman conducting soil testing" src="https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/400219/original/file-20210512-15-152kp70.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The strategy aims to train a new generation of soil experts.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>On solid ground</h2>
<p>Overall, the National Soils Strategy aims to deliver coordinated on-ground action and improve research, education and monitoring. The strategy broadly aligns with the needs of those who had input into its development, including governments, industry, academia, Landcare groups and non-government organisations. </p>
<p>However, while the importance of Indigenous land management practices is clearly acknowledged, the integration and incorporation of these practices should be more clearly defined. </p>
<p>The monitoring program encourages farmers to test their soil and incorporate the de-identified results in to the national database. Care should be taken to ensure <a href="https://ebooks.publish.csiro.au/content/soil-analysis-interpretation-manual">sampling is done appropriately</a> for the data to be useful. </p>
<p>The time frame for the initial phase of the strategy is short – pilot programs need to be delivered between two and four years. This will be challenging to deliver.</p>
<p>Separate to the strategy, the budget allocated A$59.6 million to soil carbon initiatives. There is <a href="https://www.pmc.gov.au/news-centre/domestic-policy/digging-deep-soil-organic-carbon-earth-day">increasing recognition</a> of how improved land use and management can help boost soil carbon stores, which is key to tackling climate change. But storing carbon permanently in soils comes with a number of <a href="https://theconversation.com/dishing-the-dirt-australias-move-to-store-carbon-in-soil-is-a-problem-for-tackling-climate-change-141656">challenges</a>. This funding may be appropriate only if directed to address those areas where knowledge gaps exist. </p>
<p>But overall, the strategy fills a vital gap – providing a national vision and shared goals for managing precious soils across Australia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-morrison-government-wants-to-suck-co-out-of-the-atmosphere-here-are-7-ways-to-do-it-144941">The Morrison government wants to suck CO₂ out of the atmosphere. Here are 7 ways to do it</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/160704/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa Wong receives funding from the Victorian State Government and the Australian Research Council. She is currently the President of Soil Science Australia, a not-for-profit, professional association for soil scientists and people interested in the responsible management of Australia’s soil resources.</span></em></p><p class="fine-print"><em><span>Luke Mosley receives funding from the South Australian and Commonwealth Governments for various projects. He is Immediate Past President and is affiliated with Soil Science Australia, a not-for-profit, professional association for soil scientists and people interested in the responsible management of Australia’s soil resources.</span></em></p>Soil underpins Australia’s economy – yet since Europeans arrived, the natural asset has steadily been degraded. A new national plan aims to change that.Vanessa Wong, Associate professor, Monash UniversityLuke Mosley, Associate Professor, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1416562020-08-16T20:13:59Z2020-08-16T20:13:59ZDishing the dirt: Australia’s move to store carbon in soil is a problem for tackling climate change<figure><img src="https://images.theconversation.com/files/352411/original/file-20200812-18-w2xbci.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5973%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>To slow climate change, humanity has two main options: reduce greenhouse gas emissions directly or find ways to remove them from the atmosphere. On the latter, storing carbon in soil – or carbon farming – is often touted as a promising way to offset emissions from other sources such as energy generation, industry and transport. </p>
<p>The Morrison government’s Technology Investment <a href="https://consult.industry.gov.au/climate-change/technology-investment-roadmap/supporting_documents/technologyinvestmentroadmapdiscussionpaper.pdf">Roadmap</a>, now open for public comment, identifies soil carbon as a potential way to reduce emissions from agriculture and to offset other emissions. </p>
<p>In particular, it points to so-called “biochar” – plant material transformed into carbon-rich charcoal then applied to soil. </p>
<p>But the government’s plan contains misconceptions about both biochar, and the general effectiveness of soil carbon as an emissions reduction strategy.</p>
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<img alt="Emissions rising from a coal plant." src="https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352420/original/file-20200812-21-1k6x0vf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Soil carbon storage is touted as a way to offset emissions from industry and elsewhere.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What is biochar?</h2>
<p>Through photosynthesis, plants turn carbon dioxide (CO₂) into organic material known as biomass. When that biomass decomposes in soil, CO₂ is produced and mostly ends up in the atmosphere.</p>
<p>This is a natural process. But if we can intervene by using technology to keep carbon in the soil rather than in the atmosphere, in theory that will help mitigate climate change. That’s where biochar comes in. </p>
<p>Making biochar involves heating waste organic materials in a reduced-oxygen environment to create a charcoal-like product – a process called “pyrolysis”. The carbon from the biomass is stored in the charcoal, which is very stable and does not decompose for decades. </p>
<p>Plant materials are the predominant material or “feedstock” used to make biochar, but <a href="https://pubs.acs.org/doi/10.1021/es902266r">livestock manure</a> can also be used. The biochar is applied to the soil, purportedly to boost soil fertility and productivity. This has been tested on grassland, cropping soils and in vineyards. </p>
<figure class="align-center ">
<img alt="A handful of biochar." src="https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352422/original/file-20200812-14-1c2ur8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Biochar is produced by burning organic material in a low oxygen environment.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>But there’s a catch</h2>
<p>So far, so good. But there are a few downsides to consider. </p>
<p>First, the pyrolysis process produces combustible gases and uses energy – to the extent that when all energy inputs and outputs are considered in a life cycle analysis, the net energy balance can be <a href="https://pubs.acs.org/doi/10.1021/es902266r">negative</a>. In other words, the process can create more greenhouse gas emissions than it saves. The balance depends on many factors including the type and condition of the feedstock and the rate and temperature of <a href="https://www.sciencedirect.com/science/article/pii/S0065211310050029">pyrolysis</a>.</p>
<p>Second, while biochar may improve the soil carbon status at a new site, the sites from which the carbon residues are removed, such as farmers’ fields or harvested forests, will be depleted of soil carbon and associated nutrients. Hence there may be no <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.2010.01342.x">overall</a> gain in soil fertility.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-pretty-good-start-but-room-for-improvement-3-experts-rate-australias-emissions-technology-plan-132866">A pretty good start but room for improvement: 3 experts rate Australia's emissions technology plan</a>
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<p>Third, the government roadmap claims increasing soil carbon can reduce emissions from livestock farming while increasing productivity. Theoretically, increased soil carbon should lead to better pasture growth. But the most efficient way for farmers to take advantage of the growth, and increase productivity, is to keep more livestock per hectare.</p>
<p>Livestock such as cows and sheep produce methane – a much more potent greenhouse gas than carbon dioxide. <a href="https://www.researchgate.net/publication/280743045_The_cost_effectiveness_of_a_policy_to_store_carbon_in_Australian_agricultural_soils_to_abate_greenhouse_gas_emissions_">Our analysis</a> suggests the methane produced by the extra stock would exceed the offsetting effect of storing more soil carbon. This would lead to a net increase, not decrease, in greenhouse gas </p>
<figure class="align-center ">
<img alt="Beef cattle grazing in a field" src="https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352425/original/file-20200812-18-mrza4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Farmers would have to increase stock numbers to benefit from pasture growth.</span>
<span class="attribution"><span class="source">Dan Peled/AAP</span></span>
</figcaption>
</figure>
<h2>A policy failure</h2>
<p>The government plan refers to the potential to build on the success of the <a href="http://www.cleanenergyregulator.gov.au/ERF">Emissions Reduction Fund</a>. Among other measures, the fund pays landholders to increase the amount of carbon stored in soil through carbon credits issued through the Carbon Farming Initiative. </p>
<p>However since 2014, the Emissions Reduction Fund has <a href="https://ageis.climatechange.gov.au/Chart_ANZSIC.aspx?OD_ID=1118999286">not significantly reduced</a> Australia’s greenhouse gas emissions – and agriculture’s contribution has been smaller still.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/carbon-dioxide-levels-over-australia-rose-even-after-covid-19-forced-global-emissions-down-heres-why-144119">Carbon dioxide levels over Australia rose even after COVID-19 forced global emissions down. Here's why</a>
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<p>So far, the agriculture sector has been contracted to provide <a href="http://www.cleanenergyregulator.gov.au/ERF/Auctions-results/march-2020">about 9.5%</a> of the overall abatement, or about 18.3 million tonnes. To date, it’s <a href="http://www.cleanenergyregulator.gov.au/ERF/Auctions-results/march-2020">supplied</a> only 1.54 million tonnes – 8.4% of the sector’s commitment.</p>
<p>The initiative has largely failed because several factors have made it <a href="https://iopscience.iop.org/article/10.1088/1755-1315/25/1/012004">uneconomic</a> for farmers to take part. They include:</p>
<ul>
<li>overly complex regulations </li>
<li>requirements for expensive soil sampling and analysis </li>
<li>the low value of carbon credits (averaging <a href="https://www.environment.gov.au/system/files/resources/20e963a0-0226-4131-9b88-ff0c754edea1/files/erf-what-it-means-you.pdf">$12 per tonne</a> of CO₂-equivalent since the scheme began).</li>
</ul>
<figure class="align-center ">
<img alt="A farmer inspecting crops." src="https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352871/original/file-20200814-22-1j7r208.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">For many farmers, taking part in the Emissions Reduction Fund is uneconomic.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>A misguided strategy</h2>
<p>We believe the government is misguided in considering soil carbon as an emissions reduction technology. </p>
<p>Certainly, increasing soil carbon at one location can boost soil fertility and potentially productivity, but these are largely private landholder benefits – paid for by taxpayers in the form of carbon credits.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-explained-are-we-doomed-if-we-dont-manage-to-curb-emissions-by-2030-143526">Climate explained: are we doomed if we don't manage to curb emissions by 2030?</a>
</strong>
</em>
</p>
<hr>
<p>If emissions reduction is seen as a public benefit, then the payment to farmers becomes a subsidy. But it’s highly questionable whether the public benefit (in the form of reduced emissions) is worth the cost. The government has not yet done this analysis. </p>
<p>To be effective, future emissions technology in Australia should focus on improving energy efficiency in industry, the residential sector and transport, where big gains are to be made.</p><img src="https://counter.theconversation.com/content/141656/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A federal government plan to increase soil carbon stores is a folly that misunderstands the technology.Robert Edwin White, Professor Emeritus, The University of MelbourneBrian Davidson, Senior Lecturer, Department of Agriculture and Food Systems, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1257152019-11-20T15:29:45Z2019-11-20T15:29:45ZClimate change causes sinkholes, unstable bridges and ruptured pipelines<figure><img src="https://images.theconversation.com/files/302313/original/file-20191118-169364-f55egj.jpg?ixlib=rb-1.1.0&rect=96%2C114%2C3917%2C2891&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A bus got caught in a sinkhole in downtown Pittsburgh on Oct. 28, 2019.</span> <span class="attribution"><span class="source">(Darrell Sapp/Pittsburgh Post-Gazette via AP)</span></span></figcaption></figure><p>Roads, buildings and industrial facilities rely on the integrity of the ground they’re built upon. But when soils shift or are washed away after heavy rain, severe damage can occur. </p>
<p><a href="https://www.cbc.ca/news/canada/saskatchewan/husky-energy-north-saskatchewan-river-pipeline-break-1.3855871">Ruptured pipes</a>, <a href="https://thestarphoenix.com/news/local-news/2-8-million-saskatchewan-crescent-sinkhole-fix-to-be-done-before-snow-flies">abrupt sinkholes</a>, <a href="http://www.bst-tsb.gc.ca/eng/rapports-reports/rail/2013/r13w0124/r13w0124.html">hanging railtracks</a> and <a href="https://globalnews.ca/news/4482513/geotech-study-sask-bridge-collapse-opening-day/">fallen bridges</a> can seriously compromise public safety and the environment. </p>
<p>Soils are like sponges with a network of pores that allows water and air to freely enter and escape. They can be quite stiff when they’re dry and soft when they’re wet. But some soils are more vulnerable to changes in water content than others. Alternate wetting and drying causes swelling and shrinkage in some clays, whereas freezing and thawing can weaken sandy silts.</p>
<p>In southern Saskatchewan, irregular weather patterns due to climate change affect soil moisture and adversely impact pipelines, roads and other utilities that run along the surface or are buried underground. Unless we find ways to shore up these soils or develop other alternative methods to make these grounds more stable, we face a future of interruptions and costly repairs.</p>
<h2>Problematic soils</h2>
<p>Geology, climate and environment govern the origin and evolution of soils. For example, Saskatchewan’s surface soils are made up of <a href="https://esask.uregina.ca/entry/glacial_deposition.jsp">particles deposited from glacial meltwater streams and lakes</a>. </p>
<p>Over the past 10,000 years or so, these soils have been broken down by glaciers, waters, temperatures and biological organisms (weathering) to the deposits we see today. Thick clay sediments and sandy, silty soils are common in the <a href="https://pubsaskdev.blob.core.windows.net/pubsask-prod/93756/93756-Surficial_Geology_Map_of_Saskatchewan.pdf">southern part of the province</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&rect=0%2C0%2C693%2C521&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302309/original/file-20191118-169364-11zz4j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An embankment collapsed and derailed a VIA Rail train near Togo, Sask., in April 2013.</span>
<span class="attribution"><a class="source" href="http://tsb.gc.ca/eng/enquetes-investigations/rail/2013/R13W0124/R13W0124.html">(Transportation Safety Board of Canada)</a></span>
</figcaption>
</figure>
<p>Expansive soils, such as those found in Regina, contain tiny clay particles. These particles are also negatively charged, which means that when water droplets bond to the particles, they are pushed away from one another — similar to the way two magnets will repel one another when their similar poles face each other — causing the soil to expand. When the water evaporates, the particles become close again. Soils follow this cyclic behaviour during summer and fall. </p>
<p>A similar process occurs in sandy silts, like those around Saskatoon, during winter and spring. These soils are more porous and may be generally stable, but they can also form ice lenses (flat bodies of ice) when the water freezes. This causes heave since the volume of ice is about 10 per cent more than that of water. When these lenses melt, the amount of water locally increases and the soils weaken.</p>
<h2>Soils in the future</h2>
<p>The southern part of the Prairie provinces form the Palliser’s triangle — a semi-arid steppe once considered to be unfavourable for farming owing to its <a href="https://www.thecanadianencyclopedia.ca/en/article/drought-in-pallisers-triangle-feature">dry climate</a>. In recent times, the region has been dramatically affected by climate change. The severity of <a href="https://www.cbc.ca/news/canada/saskatchewan/summer-rain-wetter-than-normal-1.5270355">extreme weather conditions, like recent wetter summers, in the area have increased</a> and it appears that the trend will continue in the future. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/urban-floods-we-can-pay-now-or-later-96160">Urban floods: We can pay now or later</a>
</strong>
</em>
</p>
<hr>
<p>In the new norm of climate change, we need to understand the behaviour of soils in terms of more frequent and much wider variations in water content. </p>
<p>My colleagues and I look at several related factors in our research studies to <a href="https://doi.org/10.1016/j.enggeo.2012.10.004">tackle the issue of problematic soils</a>, including local geology, soil properties, seasonal weather variations and the impacts of climate change. We’ve gone on to develop models that can <a href="http://www.jeionline.org/index.php?journal=mys&page=article&op=view&path%5B%5D=201200205">forecast the behaviour of these soils under atmospheric conditions</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302680/original/file-20191120-467-rv7sa8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A large sinkhole opened up in downtown Ottawa in June 2016.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Justin Tang</span></span>
</figcaption>
</figure>
<p>Our research helps others understand the different pressures various structures, such as storage tanks, residential basements, bridge piers and buried pipelines, are exposed to when they’re built into problematic soils.</p>
<p>We’re also planning to find ways to improve soil properties, using locally available and technically feasible additives. For instance, fly ash from coal burning and discarded glass bottles could be used to modify expansive soils.</p>
<p>The new backfill materials would be self-healing in the sense that they would be less vulnerable to swell-shrink and freeze-thaw cycles. Our aim is to modify soils near structures like storage tanks or pipelines so that they can withstand the harsh and exceedingly unpredictable climate now and in the future.</p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/125715/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The author receives research funding from NSERC, MITACS, TransGas Limited and Clifton Associate Limited. He has also consulted with Clifton Associates Limited. </span></em></p>Irregular weather is destabilizing the soil that supports railroad tracks, roads, buildings and pipelines.Shahid Azam, Professor - Geotechnical and Geoenvironmental Engineering, University of ReginaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1144232019-04-16T11:01:08Z2019-04-16T11:01:08ZThe dirt on soil loss from the Midwest floods<figure><img src="https://images.theconversation.com/files/269030/original/file-20190412-76856-1klbxw6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5607%2C2614&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A John Deere tractor makes its way through floodwaters in Fargo, North Dakota.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Winter-Weather-Nebraska/47013c00f0764b35a6f4718ffead2454/4/0">AP Photo/Carolyn Kaster</a></span></figcaption></figure><p>As devastating images of the 2019 Midwest floods fade from view, an insidious and longer-term problem is emerging across its vast plains: The loss of topsoil that much of the nation’s food supply relies on. </p>
<p>Today, Midwest farmers are facing millions of bushels of damaged crops such as soybean and corn. This spring’s heavy rains have already <a href="https://www.duluthnewstribune.com/news/weather/4597885-midwest-storm-brings-extreme-weather">caused record flooding</a>, which could continue into May and June, and some government officials have said it could take farmers <a href="https://www.foxbusiness.com/features/missouri-farm-bureau-president-flooding-will-take-years-to-fix">years to recover</a>. </p>
<p>Long after the rains stop, floodwaters continue to impact soil’s physical, chemical and biological properties that all plants rely on for proper growth. Just as very wet soils would prevent a homeowner from tending his or her garden, large amounts of rainfall prevent farmers from entering a wet field with machinery. Flooding can also drain nutrients out of the soil that are necessary for plant growth as well as reduce oxygen needed for <a href="https://www.hort.vt.edu/HORT6004/network/YouthGardener/Helpsheets/thingsPlantsNeed.pdf">plant roots to breathe, and gather water and nutrients</a>.</p>
<p>As scientists who have a combined 80 years of experience studying soil processes, we see clearly that many long-term problems farmers face from floodwaters are steeped in the soil. This leads us to conclude that farmers may need to take far more active measures to manage soil health in the future as weather changes occur more drastically due to climate change and other factors.</p>
<p>Here are some of the perils with flooded farmland that can affect the nation’s food supply.</p>
<h2>Suffocating soil</h2>
<p>When soil is saturated by excessive flooding, soil pores are <a href="http://www.floodsite.net/juniorfloodsite/html/en/student/thingstoknow/hydrology/waterstorage2.html">completely filled with water</a> and have little to no oxygen present. Much like humans, plants need oxygen to survive, with the gas taken into plants via leaves and roots. Also identical to humans, plants – such as farm crops – can’t breathe underwater.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/269032/original/file-20190412-76827-2psl6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A fence encrusted with ice and cornstalks stands in Nebraska floodwaters.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Winter-Weather-Nebraska/e882cfbc37524dae94fcee8a5e1e23fa/2/0">AP Photo/Nati Harnik</a></span>
</figcaption>
</figure>
<p>Essentially, excess and prolonged flooding kills plant roots because <a href="https://www.scienceabc.com/nature/why-does-over-watering-kill-plants.html">they can’t breathe</a>. Dead plant roots in turn lead to death of aboveground plant, or crop, growth.</p>
<p>Another impact of flooding is compacted soil. This often occurs when heavy machinery is run over wet or saturated farmland. When soils become compacted, future root growth and oxygen supply are limited. Thus, severe flooding can delay or even prevent planting for the entire growing season, <a href="https://www.drovers.com/article/floodwaters-threaten-millions-crop-and-livestock-losses">causing significant financial loss to farmers</a>. </p>
<h2>Loss of soil nutrients</h2>
<p>When flooding events occur, such as overwatering your garden or as with the 2019 Midwest flooding, excess water can flush nutrients out of the soil. This happens by water running offsite, leaching into and draining through the ground, or even through the conversion of nutrients from a form that plants can utilize to a gaseous form that is lost from the soil to the atmosphere. </p>
<p>Regardless of whether you are a backyard gardener or large-scale farmer, these conditions can lead to delays in crop planting, reduced crop yields, lower nutritive value in crops and increased costs in terms of extra fertilizers used. There is also the increased stress within the farming community – or for you, the backyard gardener who couldn’t plant over the weekend due to excess rainfall. This ultimately increases the risk of not producing ample food over time.</p>
<h2>Small microbial changes have big effects</h2>
<p>Flooding on grand scales causes soils to become water-saturated for longer than normal periods of time. This, in turn, affects soil microorganisms that are beneficial for nutrient cycling.</p>
<p>Flooded soils may encounter problems caused by the loss of a specific soil microorganism, <em>arbuscular mycorrhizae</em> fungi. These fungi colonize root systems in about 90% to 95% of all plants on Earth in a mutually beneficial relationship. </p>
<p>The fungi receive energy in the form of carbon from the plant. As the <a href="https://www.westernsydney.edu.au/hie/projects/how_plants_benefit_from_partnerships_with_soil_fungi">fungi extend thread-like tendrils</a> into the soil to scavenge for nutrients, they create a zone where nutrients can be taken up more easily by the plant. This, in turn, benefits nutrient uptake and nutritive value of crops.</p>
<p>When microbial activity is interrupted, nutrients don’t ebb and flow within soils in the way that is needed for proper crop growth. Crops grown in previously flooded fields may be affected due to the absence of a microbial community that is essential for maintaining proper plant growth.</p>
<p>The current Midwest flooding has far-reaching effects on soil health that may last many years. Recovering from these types of extreme events will likely require active management of soil to counteract the negative long-term effects of flooding. This may include the adoption of conservation systems that include the use of cover crops, no-till or reduced-till systems, and the use of perennials grasses, to name few. These types of systems may allow for better soil drainage and thus lessen flooding severity in soils.</p>
<p>Farmers have the ability to perform these management practices, but only if they can afford to convert over to these new systems; not all farmers are that fortunate. Until improvements in management practices are resolved, future flooding will likely continue to leave large numbers of Midwest fields vulnerable to producing lower crop yields or no crop at all.</p><img src="https://counter.theconversation.com/content/114423/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Recent extreme rains and weather in the Midwest are causing a multitude of problems in the topsoil that much of the nation’s food supply relies on.Jim Ippolito, Associate Professor of Environmental Soil Quality/Health, Colorado State UniversityMahdi Al-Kaisi, Professor of Soil Management and Environment, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1045782018-10-09T10:12:21Z2018-10-09T10:12:21Z2012 research had identified Indonesian city Palu as high risk of liquefaction<p>A 7.5 magnitude earthquake shook Donggala and Palu in the island of Sulawesi, Indonesia on September 28, 2018, causing destruction that killed more than 1700 people. Not long, the public was shocked to see on social media <a href="https://edition.cnn.com/2018/10/01/world/indonesia-earthquake-tsunami-satellite-trnd/index.html">pictures</a> and videos from the disaster location showing soil flowing like a river, dragging along and wiping out houses and trees. </p>
<p>Liquefaction is a phenomenon when the soil loses its strength due to a sudden stress such as an earthquake. Aside from shocks and the potential of water rising from a tsunami, people
also need to beware of liquefaction following an earthquake.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1048284995150737408"}"></div></p>
<p>Building houses on soil that are prone to liquefaction is extremely dangerous. The houses in the Balaroa and Petobo villages, a few kilometres from Palu, were on such land. The houses were still standing when the earthquake hit, and they were not affected by the tsunami. But moments later, thousands of houses and people in the area were swallowed to the ground because of liquefaction. </p>
<p><a href="https://www.kompas.tv/content/article/33618/video/berita-kompas-tv/likuifaksi-tenggelamkan-permukiman-balaroa-dan-petobo">A local TV station reported</a> liquefaction affected an area of 320 hectares in Palu. While the term has only been widely discussed in Indonesia and the world in the past week, Palu’s susceptibility to liquefaction had already been studied. In 2012, <a href="http://katalog.pag.geologi.esdm.go.id/dokumenview.php?ID_DOKUMEN=15540">Risna Widyaningrum from the Indonesian Geological Body conducted a study and wrote a report titled Geological Investigation of Liquefaction Potential in Palu Area, Central Sulawesi Province</a>. The report concluded that the majority area in Palu had a high potential of soil liquefaction. </p>
<h2>Ignored research</h2>
<p>Experts explain that liquefaction susceptibility is influenced by three factors: </p>
<ol>
<li> below the soil surface exists a layer of sand less than 12 meters deep, </li>
<li> the water table is below 10 meters, </li>
<li> the earthquake’s magnitude. </li>
</ol>
<p>Risna Widyaningrum’s report detailed the morphology, geology, and earthquake incidences that occur many times in the area known as <a href="https://en.wikipedia.org/wiki/Palu-Koro_Fault">Palu Koro fault</a>. The Palu Koro fault stretches 60 km long north to south crossing the city of Palu and continues to the bay of Palu next to the city of Donggala. The Palu Koro fault is moving north at a rate of 40 mm per year, faster than the <a href="https://en.wikipedia.org/wiki/Great_Sumatran_fault">Semangko Sumatra fault</a> that moves at a rate of 15 mm per year.</p>
<p>The report found that the soil in the Palu area is from alluvial sediments of the <a href="https://www.nationalgeographic.com/science/prehistoric-world/quaternary/">Quaternary period</a>. The soil is alluvium, with a sandy layer on top (1- 7m), followed by a layer of loam underneath, and finally a clay layer. A map showed that the groundwater level is considered shallow (less than 12 m from the surface). Locals said that the Bolaroa area was previously a swamp, but was built-up and made into a town. Findings from the 2012 report showed that the area is highly susceptible to liquefaction.</p>
<p>The end of the report shows three zones of liquefaction hazard: low, high, and very high risk. Petobo and Balaroa villages are in the very high-risk zone. The report recommends that building foundations should not be established on the sand layers. Also, spatial planning of housing, industry and important buildings should be made on areas of low LPI.</p>
<h2>Soil texture</h2>
<p>Soil science can explain how solid soil can move and swallow thousands of houses. </p>
<p>Soil is made up of minerals of smaller than 2 mm in diameter. These solid particles are grouped based on their sizes: the coarsest is sand (diameter 0.05 to 2 mm), silt (0.05 mm to 2 micrometers), and the finest is clay (diameter less than 2 micrometers). The mixture of these three components determine the soil textures. A coarse-textured soil has more sand and less silt and clay. There’s also medium and fine-textured soils. The coarser the texture, the more susceptible it is to be liquefied.</p>
<p>Clay holds soil particles together forming larger aggregates. Strong and stable aggregates support the growth of root plants. A tree can grow large and tall because it stands on a well-aggregated soil that support the tree. Soil with high strength forms a good foundation for buildings.</p>
<p>In between the soil particles and aggregates, there are pore spaces. These pores supply air and water to plants. The finer the pores, the stronger water is held by the soil particles. </p>
<p>Coarse-textured soils tend to have larger pores. When rain drops onto the soil, water fills the pores. When the pores are full with water, they become saturated, and further water addition will cause floods. With water inside the pores of the soil, it can also form layers within the mineral particles, diminishing the soil’s cohesive forces. Clay particles when saturated can also slake and disperse. </p>
<p>We can witness this in our daily lives. For example after a heavy rainfall you shouldn’t drive a car on a wet soil lest it’ll get stuck. A sand castle will erect tall if it has a bit of water but will collapse if it has too much. A landslide occurs when the soil “fails” because of saturation.</p>
<h2>What causes soil liquefaction</h2>
<p>When the strong earthquake shook Palu, the violent tremor underground caused groundwater to move and seep to the soil pores with high pressure. The strong and sudden pressure to the soil pores caused soil particles to disperse, losing its strength, turning into mud, bringing down any building above it. The violent shake also stir the mud and caused it to flow like river, washing away anything above it: houses, plants, and human.</p>
<p>We can do a simple test by taking a lump of sand and a lump of clay soil. If we pour a cup of water to the sand, it quickly becomes liquid. But if we pour a cup of water to clay, it tends to be stable. </p>
<p>Imagine buildings that sit on the top of these two different soils. Low-lying alluvial area that is dominated by sandy materials (thickness less than 12 m) and has a shallow water table (less than 10 m) would be highly susceptible to liquefaction.</p>
<p>The susceptibility of an area to liquefaction can be quantified using a measure called <a href="http://yo-1.ct.ntust.edu.tw/jge/files/articlefiles/v1i1200707031332604692.pdf">Liquefaction Potential Index</a> (LPI). LPI was formulated by Toshio Iwasaki in 1978, as Japan frequently suffers from earthquake and faces danger of liquefaction. LPI values below five are considered low, values between 5-15 are considered high, and above 15 are very high. </p>
<p>This index was calculated as a function of soil’s particle size and the earthquake’s strength. Areas with sandy soil with low groundwater level are considered highly susceptible to liquefaction and have LPI values greater than 15. </p>
<p>Japanese engineers also took into account this index in structural design and building zoning. This is a good example that the research finding is put in practice and serves in policy making.</p>
<p>However, as it generally happened in Indonesia, and some other countries, findings and reports made by experts were rarely followed up by policy and decision makers. We should learn from the disaster in Palu and not leave research findings unused on a shelf in the office and the library. Research dissemination on important findings such as the liquefaction susceptibility of an area should be communicated to policymakers. </p>
<p>This soil calamity can be avoided if we carefully consider the conditions of our soil and land when we build infrastructure. When building new homes for the earthquake victims policymakers and planners should pay attention to liquefaction hazardous to avoid many casualties next time the earth shakes again.</p><img src="https://counter.theconversation.com/content/104578/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Para penulis tidak bekerja, menjadi konsultan, memiliki saham atau menerima dana dari perusahaan atau organisasi mana pun yang akan mengambil untung dari artikel ini, dan telah mengungkapkan bahwa ia tidak memiliki afiliasi di luar afiliasi akademis yang telah disebut di atas.</span></em></p>While the term liquafaction has only been widely discussed in Indonesia and the world in the past week, Palu’s susceptibility to liquefy had already been studied.Dian Fiantis, Professor of Soil Science, Universitas AndalasBudiman Minasny, Professor in Soil-Landscape Modelling, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/900482018-01-17T03:15:57Z2018-01-17T03:15:57ZPost-fire mudslide problems aren’t new and likely to get worse<figure><img src="https://images.theconversation.com/files/202173/original/file-20180116-53289-438vxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As many as 20 people are dead and dozens missing following the Southern California mudslides.</span> <span class="attribution"><span class="source">AP Photo/Marcio Jose Sanchez</span></span></figcaption></figure><p>Several weeks after a series of wildfires blackened nearly 500 square miles in Southern California, a large winter storm rolled in from the Pacific. In most places the rainfall was welcomed and did not cause any major flooding from burned or unburned hillslopes. </p>
<p>But in the town of Montecito, a coastal community in Santa Barbara County that lies at the foot of the mountains blackened by the Thomas Fire, a devastating set of sediment-laden flows killed at least 20 people and damaged or destroyed more than 500 homes. In the popular press these flows were termed “mudslides,” but with some rocks as large as cars these are more accurately described as hyperconcentrated flows or debris flows, depending on the amount of sediment mixed with the water.</p>
<p>Why did these deadly flows happen? To what extent were these flows caused by the fire, the extreme burst of rainfall, or a combination? And what can we do to reduce similar risks in the future? </p>
<h2>Causes of post-fire erosion</h2>
<p>Some national newspapers are saying that these post-fire flows are caused by the loss of vegetation, but as a scientist studying the effects of fires on soils, runoff and erosion, I can say this is not completely accurate. While many wildfires do burn trees and shrubs, the loss of this overlying vegetation canopy only slightly increases the amount of rainfall that reaches the soil surface and the kinetic energy delivered by the raindrops to the ground surface.</p>
<p>The far more important effect of high and moderate severity wildfires is that they can burn off all the surface litter and ground vegetation, leaving a layer of easily removed ash on top of otherwise bare soil. </p>
<figure>
<iframe frameborder="0" class="juxtapose" width="100%" height="480" src="https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=24aee54e-fb1e-11e7-b263-0edaf8f81e27">
</iframe>
<figcaption><span class="caption">Photo from NASA Earth Observatory of the Montecito area before the Thomas fire and after the Thomas fire and the subsequent flooding and debris flows. The slider in the middle can be moved to display more of either image.</span></figcaption>
</figure>
<p>In certain vegetation types, like chaparral and coniferous forests, fires will vaporize organic compounds found in the leaf litter. Some of these compounds are driven downward by the heat where they condense on cooler soil particles just below the soil surface. In sufficient quantity and especially in coarser-textured soils, the resulting water-repellent layer impedes the normal downward flow of water. Higher-severity fires also can consume some of the shallow soil organic matter that helps bind together larger soil clumps. </p>
<p>When winds and the first rains arrive, they quickly wash the ash away, and the impact of raindrops on the bare soil can detach and <a href="https://www2.nrel.colostate.edu/assets/nrel_files/labs/macdonald-lab/pubs/SSSAJ-sealing-2009.pdf">disperse small soil particles to create a surface seal or crust</a>.</p>
<p>The net result is that after a high or moderate severity fire the ability of the soil to absorb water decreases from around several inches per hour to perhaps just one-third of an inch per hour. Any additional rainfall becomes surface runoff, and a rainstorm of only one inch per hour can generate 1.5 million cubic feet of runoff per square mile. </p>
<p>The raindrops and surface runoff can easily erode and transport the unprotected soil on the hillsides. The resulting accumulation and concentration of flow and sediment in stream channels can rapidly mobilize massive amounts of rocks and soil. </p>
<p>The resulting mixture of water, eroded soil, and rocks can quickly bulk up to a concentrated mix of water with 10 to 40 percent sediment, or an even more concentrated and deadly debris flow moving at up to <a href="https://en.wikipedia.org/wiki/Debris_flow">20 miles per hour</a>. Once these flows reach flatter areas or encounter obstacles, the velocity decreases and the rocks and mud are deposited. The potential for such flows are exacerbated in much of Southern California because the mountains are steeper than normal due to rapid uplift along regional faults.</p>
<p>With population growth there are ever more houses and other developments at the base of the mountains. Of even greater concern is the placement of houses and other structures on the <a href="https://en.wikipedia.org/wiki/Alluvial_fan">alluvial fans</a> where streams have been depositing sediment and rapidly changing their course over many thousands of years. </p>
<h2>No easy fixes</h2>
<p>When hillslopes are denuded of their surface soil cover by fire or other processes, the resulting increase in runoff and erosion is nearly inevitable. Mulch or other surface cover can be applied to help protect the soil from the raindrop impact, but mulching is difficult and expensive to quickly apply over large areas, and is progressively ineffective on steeper slopes or during more intense storms that <a href="http://dx.doi.org/10.1016/j.catena.2012.11.016">produce more surface runoff</a>. </p>
<p><a href="http://www.latimes.com/local/la-101309-me-rain-g-graphic.html">Debris basins</a> can be constructed to capture the runoff and sediment, but there are problems of finding locations and sizing their capacity for extreme events, as well clearing them prior to large storms.</p>
<p>In Montecito an exceptional storm cell developed over a severely burned area, with nearly an inch of rain in just 15 minutes and over half an inch of rain in just five minutes. Montecito is particularly at risk as the hillslopes above town are oversteepened by faulting and rapid uplift, and much of the town is built on deposits laid down by previous floods. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/202226/original/file-20180117-53324-4mni3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Dunsmir Sediment Basin in Los Angeles County, California.</span>
<span class="attribution"><a class="source" href="https://www.fema.gov/media-library/search/45017#{%22keywords%22:%2245017%22}">FEMA</a></span>
</figcaption>
</figure>
<p>Some <a href="https://fopnews.wordpress.com/2011/01/27/shape-shifters-debris-basins-and-the-san-gabriels/">debris basins</a> were in place, but they were quickly overtopped by the hundreds of thousands of cubic yards of water and sediment. While high post-fire runoff and erosion rates could be expected, it was not possible to accurately predict the exact location and extreme magnitude of this particular storm and resulting debris flows.</p>
<p>There is a long history of comparable post-fire debris flows in the Los Angeles area with a <a href="https://pubs.usgs.gov/wsp/0796c/report.pdf">greater loss of life</a>. Comparable events also <a href="http://boisestatepublicradio.org/post/landslide-buried-boise-mud-55-years-ago-scientists-say-it-could-happen-again#stream/0">have occurred</a> <a href="http://www.azgs.az.gov/arizona_geology/winter10/article_feature.html">elsewhere in the western U.S.</a>, but in most cases the consequences have been much less tragic because wildfires more commonly occur in much less populated areas. This means the resultant effects are often limited to degraded <a href="http://www.clrma.org/files/springconference/Strontia%20Springs%20Sediment%20Removal%204-17-14%20Update.pdf">water quality, loss of aquatic habitat and excess reservoir sedimentation</a>.</p>
<h2>What next?</h2>
<p>Looking to the future, it is very clear that the problem is only going to get worse. </p>
<p>First, climate change is increasing the length and severity of the fire season by <a href="http://www.pnas.org/content/107/45/19167">reducing snowpacks and increasing temperatures</a>. Warmer temperatures increase <a href="https://theconversation.com/wildfires-in-west-have-gotten-bigger-more-frequent-and-longer-since-the-1980s-42993">fire risk</a> as well as the capacity of the atmosphere to hold water, which is <a href="http://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-12-00502.1">increasing rainfall intensities</a>. </p>
<p>Second, a policy of <a href="https://dx.doi.org/10.1126/science.1240294">suppressing wildfires</a> has increased the amount and density of vegetation in some areas. This greater fuel load can result in higher severity fires and more denuded hillslopes. Future wildfires are inevitable, and when there are high temperatures, high winds, low humidity and large fuel loads, it is not possible to safely fight or control a large wildfire. </p>
<p>Nor is it possible to stop the subsequent hillslope runoff and erosion. Debris basins or diversion structures can be built to reduce damage, but these are expensive and often do not have sufficient capacity for extreme post-fire storm events. While we are getting much better at predicting the risk of sediment-laden flows after wildfires through <a href="https://landslides.usgs.gov/hazards/">improved modeling and weather forecasting</a>, the starting point has to be <a href="https://theconversation.com/deadly-california-mudslides-show-the-need-for-maps-and-zoning-that-better-reflect-landslide-risk-90087">stricter zoning rules</a> to minimize construction in vulnerable areas. And once an area does burn, residents must heed the calls for evacuation when post-fire rainstorms are predicted.</p>
<p>On the positive side, most burned areas generally revegetate within two to four years. Once there is less than about 30-35 percent bare soil, there is a <a href="https://www2.nrel.colostate.edu/assets/nrel_files/labs/macdonald-lab/pubs/SSSAJ-sealing-2009.pdf">greatly reduced risk</a> of high runoff and erosion rates.</p>
<p>In Montecito the rapid delineation of risk zones led to the evacuations that undoubtedly helped save many hundreds of lives. What is now important is that the lessons from the Thomas Fire are applied in other areas to help minimize future losses of life and property. This is true in both the short term as more rain falls on the recently burned areas, and over the longer term given our increasingly fire-prone future.</p><img src="https://counter.theconversation.com/content/90048/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lee MacDonald receives funding from the National Science Foundation, USDA Forest Service, CAL-FIRE, and U.S. Army Corps of Engineers. </span></em></p>A watershed scientist explains why post-wildfire landscapes are so susceptible to landslides – and why those risks are poised to rise.Lee MacDonald, Professor of Ecosystem Science and Sustainability, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/753642017-04-04T00:45:22Z2017-04-04T00:45:22ZHealthy soil is the real key to feeding the world<figure><img src="https://images.theconversation.com/files/163183/original/image-20170329-8557-1q1xe1z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Planting a diverse blend of crops and cover crops, and not tilling, helps promote soil health.
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/87743206@N04/8053614949/in/dateposted/">Catherine Ulitsky, USDA/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>One of the biggest modern myths about agriculture is that organic farming is inherently sustainable. It can be, but it isn’t necessarily. After all, soil erosion from chemical-free tilled fields undermined the Roman Empire and other ancient societies <a href="http://www.ucpress.edu/book.php?isbn=9780520272903">around the world</a>. Other agricultural myths hinder recognizing the potential to restore degraded soils to feed the world using fewer agrochemicals. </p>
<p>When I embarked on a six-month trip to visit farms around the world to research my forthcoming book, <a href="http://books.wwnorton.com/books/detail.aspx?ID=4294993513">“Growing a Revolution: Bringing Our Soil Back to Life,”</a> the innovative farmers I met showed me that regenerative farming practices can restore the world’s agricultural soils. In both the developed and developing worlds, these farmers rapidly rebuilt the fertility of their degraded soil, which then allowed them to maintain high yields using far less fertilizer and fewer pesticides. </p>
<p>Their experiences, and the results that I saw on their farms in North and South Dakota, Ohio, Pennsylvania, Ghana and Costa Rica, offer compelling evidence that the key to sustaining highly productive agriculture lies in rebuilding healthy, fertile soil. This journey also led me to question three pillars of conventional wisdom about today’s industrialized agrochemical agriculture: that it feeds the world, is a more efficient way to produce food and will be necessary to feed the future. </p>
<h2>Myth 1: Large-scale agriculture feeds the world today</h2>
<p>According to a recent U.N. Food and Agriculture Organization (FAO) report, family farms produce over <a href="http://www.fao.org/news/story/en/item/260535/icode/">three-quarters of the world’s food</a>. The FAO also estimates that almost three-quarters of all farms worldwide are <a href="http://www.fao.org/fileadmin/user_upload/hlpe/hlpe_documents/HLPE_Reports/HLPE-Report-6_Investing_in_smallholder_agriculture.pdf">smaller than one hectare</a> – about 2.5 acres, or the size of a typical city block. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163190/original/image-20170329-8587-n5b1ng.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Ugandan farmer transports bananas to market. Most food consumed in the developing world is grown on small family farms.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ifpri/12209977313/in/album-72157640285734626/">Svetlana Edmeades/IFPRI/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Only about 1 percent of Americans are farmers today. Yet most of the world’s farmers work the land to feed themselves and their families. So while conventional industrialized agriculture feeds the developed world, most of the world’s farmers work small family farms. A 2016 Environmental Working Group report <a href="http://www.ewg.org/research/feeding-the-world">found</a> that almost 90 percent of U.S. agricultural exports went to developed countries with few hungry people. </p>
<p>Of course the world needs commercial agriculture, unless we all want to live on and work our own farms. But are large industrial farms really the best, let alone the only, way forward? This question leads us to a second myth.</p>
<h2>Myth 2: Large farms are more efficient</h2>
<p>Many high-volume industrial processes exhibit efficiencies at large scale that decrease inputs per unit of production. The more widgets you make, the more efficiently you can make each one. But agriculture is different. A 1989 National Research Council study <a href="https://www.nap.edu/catalog/1208/alternative-agriculture">concluded</a> that “well-managed alternative farming systems nearly always use less synthetic chemical pesticides, fertilizers, and antibiotics per unit of production than conventional farms.” </p>
<p>And while mechanization can provide cost and labor efficiencies on large farms, bigger farms do not necessarily produce more food. According to a 1992 agricultural census report, small, diversified farms produce more than twice as much food per acre <a href="http://www.ucpress.edu/book.php?isbn=9780520272903">than large farms do</a>. </p>
<p>Even the <a href="http://documents.worldbank.org/curated/en/595651468195548184/On-the-central-role-of-small-farms-in-African-rural-development-strategies">World Bank</a> endorses small farms as the way to increase agricultural output in developing nations where food security remains a pressing issue. While large farms excel at producing a lot of a particular crop – like corn or wheat – small diversified farms produce more food and more kinds of food per hectare overall. </p>
<h2>Myth 3: Conventional farming is necessary to feed the world</h2>
<p>We’ve all heard proponents of conventional agriculture claim that organic farming is a recipe for global starvation because it produces lower yields. The most extensive yield comparison to date, <a href="http://dx.doi.org/10.1098/rspb.2014.1396">a 2015 meta-analysis</a> of 115 studies, found that organic production averaged almost 20 percent less than conventionally grown crops, a finding similar to those of prior studies. </p>
<p>But the study went a step further, comparing crop yields on conventional farms to those on organic farms where cover crops were planted and crops were rotated to build soil health. These techniques shrank the yield gap to below 10 percent. </p>
<p>The authors concluded that the actual gap may be much smaller, as they found “<a href="http://dx.doi.org/10.1098/rspb.2014.1396">evidence of bias in the meta-dataset toward studies reporting higher conventional yields</a>.” In other words, the basis for claims that organic agriculture can’t feed the world depend as much on specific farming methods as on the type of farm. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163194/original/image-20170329-8563-1hdfyfr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cover crops planted on wheat fields in The Dalles, Oregon.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nrcs_oregon/29653107380/in/album-72157674420338935/">Garrett Duyck, NRCS/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Consider too that about a quarter of all food produced worldwide is never eaten. Each year the United States alone throws out <a href="http://www.endhunger.org/PDFs/2014/USDA-FoodLoss-2014.pdf">133 billion pounds of food</a>, more than enough to feed the nearly 50 million Americans who regularly face hunger. So even taken at face value, the oft-cited yield gap between conventional and organic farming is smaller than the amount of food we routinely throw away. </p>
<h2>Building healthy soil</h2>
<p>Conventional farming practices that degrade soil health undermine humanity’s ability to continue feeding everyone <a href="http://www.ucpress.edu/book.php?isbn=9780520272903">over the long run</a>. Regenerative practices like those used on the farms and ranches I visited show that we can readily improve soil fertility on both large farms in the U.S. and on small subsistence farms in the tropics. </p>
<p>I no longer see debates about the future of agriculture as simply conventional versus organic. In my view, we’ve oversimplified the complexity of the land and underutilized the ingenuity of farmers. I now see adopting farming practices that build soil health as the key to a stable and resilient agriculture. And the farmers I visited had cracked this code, adapting <a href="https://www.washingtonpost.com/news/wonk/wp/2013/11/09/no-till-farming-is-on-the-rise-thats-actually-a-big-deal/?utm_term=.e2cf5e93305e">no-till methods</a>, cover cropping and complex rotations to their particular soil, environmental and socioeconomic conditions.</p>
<p>Whether they were organic or still used some fertilizers and pesticides, the farms I visited that adopted this transformational suite of practices all reported harvests that consistently matched or exceeded those from neighboring conventional farms after a short transition period. Another message was as simple as it was clear: Farmers who restored their soil <a href="http://books.wwnorton.com/books/detail.aspx?ID=4294993513">used fewer inputs to produce higher yields</a>, which translated into higher profits. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=899&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=899&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=899&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163674/original/image-20170403-21969-1bmzm3i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Soil building practices, like no-till and composting, can build soil organic matter and improve soil fertility (click to zoom).</span>
<span class="attribution"><span class="source">David Montgomery</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>No matter how one looks at it, we can be certain that agriculture will soon face another revolution. For agriculture today runs on abundant, cheap oil for fuel and to make fertilizer – and our supply of cheap oil will not last forever. There are already enough people on the planet that we have <a href="http://www.resilience.org/stories/2006-10-28/how-long-can-world-feed-itself/">less than a year’s supply of food</a> for the global population on hand at any one time. This simple fact has critical implications for society. </p>
<p>So how do we speed the adoption of a more resilient agriculture? Creating demonstration farms would help, as would carrying out system-scale research to evaluate what works best to adapt specific practices to general principles in different settings. </p>
<p>We also need to reframe our agricultural policies and subsidies. It makes no sense to continue incentivizing conventional practices that degrade soil fertility. We must begin supporting and rewarding farmers who adopt regenerative practices.</p>
<p>Once we see through myths of modern agriculture, practices that build soil health become the lens through which to assess strategies for feeding us all over the long haul. Why am I so confident that regenerative farming practices can prove both productive and economical? The farmers I met showed me they already are.</p><img src="https://counter.theconversation.com/content/75364/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David R. Montgomery does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Conventional wisdom says we need industrial agriculture to feed the world. Not so, says geologist David Montgomery: Practices that focus on creating healthy soil can transform agriculture.David R. Montgomery, Professor of Earth and Space Sciences, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/653322016-09-27T19:21:23Z2016-09-27T19:21:23ZFertile ground: what you need to know about soil to keep your garden healthy<figure><img src="https://images.theconversation.com/files/138193/original/image-20160919-16988-h2qmmz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Soil needs the right structure and microbial ecology to help your plants grow. </span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>As the weather warms and days lengthen, your attention may be turning to that forgotten patch of your backyard. This week we’ve asked our experts to share <a href="https://theconversation.com/au/topics/gardening-series-31530">the science behind gardening</a>. So grab a trowel and your green thumbs, and dig in.</em></p>
<hr>
<p>Most people think of soil only in terms of the dirt that sticks stubbornly to their hands and shoes. But soil is much more than that. </p>
<p>A handful of soil is a small and very complex ecosystem which includes soil particles, pores, aggregates, organic matter and a staggering number of microorganisms, all of which interact to keep the soil healthy and productive. </p>
<p>Each soil is different. The primary factor determining the physical properties of a soil is particle size. Sandy soils have a coarse structure, large pores and little ability to hold on to water and nutrients, which makes them prone to leaching. </p>
<p>Clayey soils hold nutrients and water, but because the pores are small they are prone to waterlogging. </p>
<p>The pores between soil particles are important for water flow but also for the movement of gases. Particularly important is the exchange of oxygen with the atmosphere, because plant roots and most soil organisms need oxygen to breathe. </p>
<p>Sand, silt and clay particles are bound together to form aggregates. These aggregates form the skeleton, or matrix, for chemical and biological processes which are critical for soil functions. </p>
<h2>Nitty-gritty</h2>
<p>Organic matter and soil microorganisms play key roles in the formation and stability of aggregates. </p>
<p>Think of organic matter as being the glue or mortar between soil particles. But the organic matter needs be decomposed to be most effective. And this is where soil microorganisms come in. </p>
<p>Each gram of soil contains a billion bacteria, which is almost as much as the human population of China or India, and about 50 times the number of people in Australia. </p>
<p>And this number does not even include soil fungi. All these bacteria and fungi can coexist because they have different needs or don’t interact. </p>
<p>For example, a bacterium on one side of the aggregate is quite isolated from a bacterium on the other side of the same aggregate. So even if these two bacteria have similar needs, they don’t compete. </p>
<p>They may also not compete because they are not active at the same time. In a given soil condition, only a small proportion of the bacterial population is active. The majority are inactive (dormant) and come to life only when conditions are optimal for them. </p>
<p>Another reason for the staggering number of microbes in a gram of soil is the huge diversity. A gram of soil contains around a million different species. Among them are generalists but there are also specialists, such as those capable of fixing nitrogen from the atmosphere or degrading wood. </p>
<p>The food of the vast majority of soil microbes is organic matter, which is mainly plant matter. When plant matter gets into the soil, it is attacked by soil microbes for energy and nutrients. </p>
<p>This attack is aided by soil animals such as earthworms or mites. They mix the plant matter in the soil and its microbes, fragmenting it and thereby improving contact between plant matter and soil organisms. </p>
<p>During decomposition of plant matter, microbes multiply and produce carbon dioxide and nutrients for plant uptake. The dead microbes and the components of the plant matter that are very difficult to decompose help to bind the soil particles together.</p>
<p>This binding is also aided by slimes produced by microbes and the long filaments of <a href="http://website.nbm-mnb.ca/mycologywebpages/NaturalHistoryOfFungi/Thallus.html">fungal hyphae</a>. The aggregates formed in this way are stable, which is important for adequate water and air supply for plant roots and soil organisms. </p>
<p>If aggregates are not stable, such as in sodic soils, water and air supply are restricted and plants and soil organisms will suffer.</p>
<h2>Feeding your soil</h2>
<p>Maintaining a certain level of organic matter in soil is critical for sustained soil health and function. Organic matter not only ensures that aggregates are stable, but also acts like a sponge, holding water, which is particularly important in sandy soils. </p>
<p>Another important function of organic matter is supply of nutrients required by plants. As mentioned above, decomposition of plant matter releases nutrients and it also can bind nutrients which can become available later. </p>
<p>But organic matter also decomposes, so needs to be replaced regularly. You can do this by adding plant matter growing in your garden or from outside to the soil, either directly or after composting. </p>
<p>Compost is more stable in soil than litter or straw because it is already decomposed during the composting process. It is a good glue for soil particles and binds nutrients, but it will not supply much nutrients for plants. </p>
<p>Fresh young plant matter is a good source of nutrients, but also decomposes very quickly and may initially release more nutrients than the plants can take up. </p>
<p>Mature cereal straw is nutrient-poor and decomposes slowly. So for good nutrient supply and long-term soil productivity, you may have to supply a mix of different types of organic amendments. </p>
<p>Of course, you can bypass this organic loop by adding inorganic fertilisers. Plants will grow well, but you have to match supply and plant demand carefully, because most fertilisers are dissolved quickly. </p>
<p>In your garden, you may get the best results by combining organic and inorganic fertilisation: various organic amendments for long-term soil health and stability, and inorganic fertiliser to overcome short-term nutrient deficiencies.</p><img src="https://counter.theconversation.com/content/65332/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Petra Marschner receives funding from Australian Research Council. </span></em></p>Soil is more than just dirt. It’s a complex ecosystem and if it’s healthy your plants will be happier.Petra Marschner, Professor of Agriculture, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/630072016-09-12T15:39:59Z2016-09-12T15:39:59ZWhy boosting legume production will lift the gloom for African farmers<figure><img src="https://images.theconversation.com/files/137053/original/image-20160908-25266-ge22sj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A farm employee walks through a soya bean field in northern Uganda. </span> <span class="attribution"><span class="source">Reuters/James Akena</span></span></figcaption></figure><p>Africa has the <a href="https://openknowledge.worldbank.org/bitstream/handle/10986/6650/390370AFR0Fert101OFFICIAL0USE0ONLY1.pdf?sequence=1">lowest use of nitrogen</a> on its farmland compared to other regions of the world. This is because smallholder farmers have limited financial resources to buy fertilisers. Nitrogen is one of the most essential nutrients needed by plants for their growth, development and reproduction. Yet it is <a href="http://www.nature.com/news/african-agriculture-dirt-poor-1.10311">depleted</a> in most African soils.</p>
<p>Soil depletion over the years has led farmers to open new land to maintain their production. This has often led to increased deforestation and encroachment on marginal areas. The result over time has been declining farm production and family incomes as well as poor nutrition.</p>
<p>Empowering farmers to increase legume production can turn the tide for African farmers. Grain legumes are rich in carbohydrates, minerals and are a cheap source of <a href="http://ajcn.nutrition.org/content/70/3/439s.full">protein</a>. They improve soil fertility by capturing nitrogen gas in the air and bringing it into the soil. The amount of atmospheric nitrogen fixed by legumes into usable nitrogen can be substantial. </p>
<p>Any portion of a legume crop that is left after harvest, including roots and nodules, can supply nitrogen to the soil system when the plant material is decomposed. In addition, the harvest residue provides high-quality feed for livestock. This is because it is rich in protein.</p>
<h2>Benefits of legume production</h2>
<p>Smallholder farmers in Africa who grow legumes such as soybean, beans, groundnut and chickpeas among smallholder farmers in Africa experience three immediate benefits: </p>
<ul>
<li><p>It improves the health and nutrition of families and their livestock, </p></li>
<li><p>Enhances soil <a href="http://www.fao.org/english/newsroom/highlights/2001/010403-e.htm">fertility</a> and;</p></li>
<li><p>Increases incomes, contributing to <a href="http://grainlegumes.cgiar.org/why-grain-legumes-matter/reducing-rural-poverty/">reducing rural poverty</a>.</p></li>
</ul>
<p>These reasons lie behind the major science-based farmer support project <a href="http://www.n2africa.org/">N2Africa</a>, launched in 2009. Its objective is to boost legume production in sub-Saharan Africa to address food and nutrition insecurity and to increase rural communities’ incomes.</p>
<p>The large scale research-based project is focused on delivery and dissemination of the best available legume technologies. Building sustainable, long term partnerships with smallholder farmers is central to the plan. </p>
<p>The work is being carried out in 11 African countries: Democratic Republic of Congo, Ethiopia, Ghana, Kenya, Malawi, Mozambique, Nigeria, Rwanda, Tanzania, Uganda and Zimbabwe.</p>
<p>In the short term, the project seeks to demonstrate the benefits of legume production. In the long term the aim is to develop sustainable systems for:</p>
<ul>
<li><p>Supply of inputs such as fertilisers and seeds </p></li>
<li><p>Strengthening the ability of farmers to market and;</p></li>
<li><p>Tackling constraints of legume productivity along the value chain </p></li>
</ul>
<p>In its first phase, the project reached more than 230,000 farmers who evaluated and tried out the technologies being promoted such as improved grain legume varieties, phosphate based fertilisers and <a href="http://www.n2africa.org/node/39">rhizobia inoculants</a> on their farms. The latter are root-nodule bacteria that support the legumes to fix nitrogen. </p>
<h2>Promoting fertiliser blends</h2>
<p>A majority of smallholder farmers grow their legumes without fertilisers. Fertilisers are expensive and are also not blended. This means they do not have the correct composition of minerals required by legumes.</p>
<p>The ongoing initiative is promoting the use of fertilisers, especially blended for legumes and biofertilisers. While biofertilisers are more affordable than mineral fertilisers and have great potential to increase yield, they are not widely used in sub-Saharan Africa. This is due to low levels of awareness and a lack of favourable environmental policies. There are also no proper public-private partnerships to commercialise the technology. </p>
<p>The introduction of several commercial rhizobia inoculant products is under way. To achieve this, N2Africa is building researchers’ capacity to isolate African rhizobia and identify effective strains for formulation of legume inoculants. It’s also important that the capacity of regulatory authorities to test products for quality and to formulate standards is enhanced.</p>
<h2>Catering for different circumstances</h2>
<p>The circumstances differ widely between countries or regions and for each specific crop. Current work involves actively engaging with suppliers to ensure a sustainable supply of inputs. This includes seeds, high-quality inoculants and legume-specific fertilisers. A lot of effort has gone into strengthening the ability of farmer organisations to aggregate their grain for joint marketing. </p>
<p>Thanks to this initiative, farmers are using improved seeds, fertilisers and inoculants to increase legume productivity. Seed companies and agro-dealers are strengthening inputs supplies systems. On the other hand, the farmers are better organised and are selling their produce at competitive prices. </p>
<p>The project’s goal is to reach 780,000 beneficiaries by 2018 across the 11 countries. The objective is to nurture a vibrant organised legume value chain that helps improve the health and nutritional status of smallholder farmers, reduces poverty and improves soil fertility.</p><img src="https://counter.theconversation.com/content/63007/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frederick Baijukya acknowledges the contribution of Catherine Njuguna, who works for the International Institute of Tropical Agriculture (IITA) as a Communications Officer. IITA is one of the main partners of the N2Africa initiative.</span></em></p><p class="fine-print"><em><span>Fred Kanampiu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Increasing legume production can turn the tide for African farmers who struggle with poor soils, declining farm yields and worsening nutrition in one fell swoopFrederick Baijukya, Researcher & Country Co-ordinator N2Africa, International Institute of Tropical Agriculture (IITA)Fred Kanampiu, Researcher & Project Co-ordinator N2Africa, International Institute of Tropical Agriculture (IITA)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/647572016-09-04T17:44:14Z2016-09-04T17:44:14ZAfrica needs to move faster to deliver life-saving soil science solutions<figure><img src="https://images.theconversation.com/files/136402/original/image-20160902-20238-r9hp6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers at several institutions are searching for microbial solutions for Africa’s low-performing staple crops</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Not many years ago, global health advocates bemoaned the fact that it took decades for life-saving vaccines to become widely accessible in poorer countries. This resulted in the unnecessary deaths of millions of children every year. Today, however, childhood vaccines are available <a href="http://www.who.int/mediacentre/factsheets/fs378/en/">nearly everywhere</a>. This was thanks to global partnerships between governments, industry and philanthropists.</p>
<p>Unfortunately, the same is not true of agricultural technologies, which can also be life-saving. In poor countries, low agricultural productivity and soil degradation are <a href="ftp://ftp.fao.org/docrep/fao/010/ai799e/ai799e02.pdf">factors driving</a> chronic hunger and malnutrition and associated sickness and premature death. Indeed, <a href="http://www.who.int/mediacentre/factsheets/fs178/en/">malnutrition</a> contributes to almost half of all child deaths.</p>
<p>But the current revolution in agricultural technology that is <a href="http://www.pbs.org/wgbh/nova/next/nature/more-food-with-microbes/">reshaping</a> Western agriculture is yet to reach poor countries in Africa. This is certainly the case when it comes to agricultural products based on the use of <a href="http://blogs.scientificamerican.com/guest-blog/how-soil-microbes-fight-climate-change/">soil microbes</a>. These are naturally occurring microorganisms like bacteria and fungi.</p>
<h2>Best-kept secret</h2>
<p>Microbial-based solutions are perhaps the best-kept secret among the innovations driving agriculture today. Much more is commonly known about precision techniques, drones and satellite data. Yet in developed countries microbial-based solutions are a <a href="http://www.biofuelsdigest.com/bdigest/2015/02/16/innovation-and-investment-in-agtech-the-what-when-who-why-and-how/">$2.3 billion market</a> – and <a href="https://research01.agfunder.com/2015/AgFunder-AgTech-Investing-Report-2015.pdf">growing</a>. </p>
<p>Microbial-based solutions also have funds and support from the largest corporations in agriculture.</p>
<p>Monsanto and Novozymes created the <a href="http://www.monsantobioag.com/Pages/bioag-alliance.aspx">BioAg Alliance</a>. This long-term strategic parternship brings together their capabilities in microbial discovery, development and production. $300 million was put in for research and development. In addition, Bayer Crop Sciences developed <a href="https://www.cropscience.bayer.us/products/seedgrowth/poncho-votivo">Poncho®/Votivo®</a>, a biological seed treatment. This product protects young soybean plants from pests. It also improves root growth and <a href="https://www.cropscience.bayer.us/products/seedgrowth/poncho-votivo/trial-data-corn">increases yields</a> by 15%. </p>
<p>Other <a href="https://agfundernews.com/innovation-investment-agtech.html">companies</a> that have invested in this area include <a href="http://agbiome.com/whoisagbiome/">Agbiome</a>, a biotechnology company using knowledge of plant-associated microbiome to create innovative products for agriculture, and <a href="http://bioconsortia.com/">Bioconsortia</a>, a company specialising in the discovery and development of natural microbial products. There’s also <a href="http://symbiota.com/about-us/overview/">Symbiota</a>, a company developing microbial solutions for agriculture.</p>
<h2>Microbial products</h2>
<p>Microbial products are so exciting partly because they are derived from naturally occurring microorganisms such as bacteria and fungi. These microscopic creatures form mutually beneficial associations with plants including maize, tomatoes and peppers. </p>
<p>They help improve soil fertility and strengthen plant defences against insect pests and diseases. They also help plants tolerate extreme temperature fluctuations that come with a changing climate. They have the potential to <a href="http://webcache.googleusercontent.com/search?q=cache:RI3RJBvT0KcJ:news.nationalgeographic.com/news/2014/09/140918-soil-bacteria-microbe-farming-technology-ngfood/+&cd=1&hl=en&ct=clnk">improve agriculture</a> and help humanity <a href="http://www.cropsreview.com/agricultural-productivity.html">feed the growing population</a> in a changing climate while protecting the environment.</p>
<p>In Africa, microbial science for agriculture is just getting started. Yet it is here where there is an overwhelming need to improve crop productivity and soil health. </p>
<p>Some 65% of African farmland is <a href="http://www.dailymanagementreview.com/65-of-Africa-arable-land-is-damaged-and-of-poor-quality_a253.html">degraded</a>. Unhealthy and degraded soils are a major obstacle to food security and development. They also cost African farmers $68 billion <a href="http://ag4impact.org/wp-content/uploads/2014/12/MP_0106_Soil_Report_LR1.pdf">annually</a>. Crops grown in depleted soils are nutrient-poor and low-yielding. Indeed, yields for several staple food crops in sub-Saharan Africa have <a href="http://www.un.org/millenniumgoals/pdf/nyas_building_agra.pdf">remained stagnant</a> for decades.</p>
<h2>Searching for solutions</h2>
<p>Researchers at several institutions are searching for microbial solutions for Africa’s low-performing staple crops. </p>
<p>The <a href="https://www.jic.ac.uk/">John Innes Centre</a> based in the UK is leading an <a href="https://www.jic.ac.uk/news/2012/07/cereals-self-fertilise/">investigation</a> into whether bacteria can be tapped to help cereal crops access nitrogen and help improve yields. <a href="http://agbiome.com/">AgBiome</a> was recently awarded a <a href="http://agbiome.com/agbiome-awarded-grant-from-bill-melinda-gates-foundation/">multi-year grant</a> by the Bill & Melinda Gates Foundation to discover beneficial microbes with the ability to control sweet potato weevils. </p>
<p>This is a beginning. But to catch up with the rest of the world, Africa needs to move faster. A unified microbial research initiative is needed. This would bring together research institutions, private industry and funding agencies and could help lobby resources. </p>
<p>The good will is already there. In 2012 a <a href="http://cavs.uonbi.ac.ke/node/125">conference</a> in Nairobi, Kenya, highlighted the need to identify and advance proven microbial-based agricultural technologies. But a formal, ongoing initiative is needed to follow through on the promise of soil microbial science for Africa.</p>
<p>Healthy soils underpin agriculture and therefore should be given a top priority.</p><img src="https://counter.theconversation.com/content/64757/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>was a New Voices Fellow. New Voices is funded by Bill and Melinda Gates Foundation</span></em></p>Microbial-based solutions are perhaps the best-kept secret in agricultural innovation.Esther Ndumi Ngumbi, Research Fellow, Department of Entomology and Plant Pathology, Auburn UniversityLicensed as Creative Commons – attribution, no derivatives.