Arguments
Peak Water, Peak Oil…Now, Peak Soil?
Posted on 16 June 2013 by John Hartz
The following article is reprinted by permission of its author, Stephen Leahy, who writes for the Inter Press Service (IPS) News Agency. To access the article as posted on the IPS website, click here.
Healthy soil looks dark, crumbly, and porous, and is home to worms and other organisms. It feels soft, moist, and friable, and allows plant roots to grow unimpeded. Credit: Colette Kessler, USDA Natural Resources Conservation Service
- Soil is becoming endangered.This reality needs to be part of our collective awareness in order to feed nine billion people by 2050, say experts meeting here in Reykjavík.
And a big part of reversing soil decline is carbon, the same element that is overheating the planet.
“Keeping and putting carbon in its rightful place” needs to be the mantra for humanity if we want to continue to eat, drink and combat global warming, concluded 200 researchers from more than 30 countries.
“There is no life without soil,” said Anne Glover, chief scientific advisor to the European Commission.
“While soil is invisible to most people it provides an estimated 1.5 to 13 trillion dollars in ecosystem services annually,” Glover said at the Soil Carbon Sequestration conference that ended this week.
The dirt beneath our feet is a nearly magical world filled with tiny, wondrous creatures. A mere handful of soil might contain a half million different species including ants, earthworms, fungi, bacteria and other microorganisms. Soil provides nearly all of our food – only one percent of our calories come from the oceans, she said.
Soil also gives life to all of the world’s plants that supply us with much of our oxygen, another important ecosystem service. Soil cleans water, keeps contaminants out of streams and lakes, and prevents flooding. Soil can also absorb huge amounts of carbon, second only to the oceans.
“It takes half a millennia to build two centimetres of living soil and only seconds to destroy it,” Glover said.
Each year, 12 million hectares of land, where 20 million tonnes of grain could have been grown, are lost to land degradation. In the past 40 years, 30 percent of the planet’s arable (food-producing) land has become unproductive due to erosion. Unless this trend is reversed soon, feeding the world’s growing population will be impossible.
The world will likely need “60 percent more food calories in 2050 than in 2006″, according to a new paper released May 30 by the World Resources Institute. Reaching this goal while maintaining economic growth and environmental sustainability is one of the most important global challenges of our time, it concludes.
Urban development is a growing factor in loss of arable lands. One million city dwellers occupy 40,000 hectares of land on average, said Rattan Lal of Ohio State University.
Plowing, removal of crop residues after harvest, and overgrazing all leave soil naked and vulnerable to wind and rain, resulting in gradual, often unnoticed erosion of soil. This is like tire wear on your car – unless given the attention and respect it deserves, catastrophe is only a matter of time.
Erosion also puts carbon into the air where it contributes to climate change. But with good agricultural practices like using seed drills instead of plows, planting cover crops and leaving crop residues, soils can go from a carbon source to a carbon solution, he said.
“Soil can be a safe place where huge amounts of carbon from the atmosphere could be sequestered,” Lal told IPS.
When a plant grows it takes CO2 out the atmosphere and releases oxygen. The more of a crop – maize, soy or vegetable – that remains after harvest, the more carbon is returned to the soil. This carbon is mainly found in humus – the rich organic material from decay of plant material. Soil needs to contain just 1.5 percent carbon to be healthy and resilient – more capable of withstanding drought and other harsh conditions.
“Healthy soils equals healthy crops, healthy livestock and healthy people,” Lal said.
However, most soils suffer from 30 to 60 percent loss in soil carbon. “Soils are like a bank account. You should only draw out what you put in. Soils are badly overdrawn in most places.”
Farmers and pastoralists (ranchers) could do “miracles” in keeping carbon in the soil and helping to pull carbon out of the atmosphere and feed the world if they were properly supported, Lal said.
The world’s 3.4 billion ha of rangeland and pastures has the potential to sequester or absorb up to 10 percent of the annual carbon emissions from burning fossil fuels and cement production, estimates Ólafur Arnalds, a soil scientist at the Agricultural University of Iceland.
Eliminating overgrazing and using other pasture management techniques will reduce the number of animals on the land in the short term but it is better for the long term health of grazing lands. While these practises can help with climate change, there many other good reasons to adopt them, Arnalds told IPS.
That view is echoed by many here since determining exactly how much carbon a farm field or pasture can absorb from the atmosphere is highly variable and difficult to determine.
Proper land management can help with climate change but in no way does it reduce the need to make major reductions in fossil fuel use, said Guðmundur Halldórsson, a research co-ordinator at the Soil Conservation Service of Iceland, co-host of the conference.
And using farmland or pastures as a ‘carbon sponges’ will lead to all sorts of problems, Halldórsson told IPS.
“The real key is adopt practices that enhance soil health to improve food productivity,” he said.
That approach is much more likely to help in improve local livelihoods, protect water resources, improve biodiversity, reduce erosion and help put carbon back into the ground where it belongs, he said.
“Iceland overexploited its lands, trying to squeeze more out of the land than it could handle. We call it ‘killing the milk cow’. We can no longer live off the land as we once did.”
Situated in the North Atlantic, the windy island was once mostly covered by forests, lush meadows and wetlands when the first settlers arrived nearly 1,000 years ago. By the late 1800s, 96 percent of the forest was gone and half the grasslands destroyed by overgrazing. Iceland became one the world’s poorest countries, its people starved and its landscape remains Europe’s largest desert.
Of necessity, Iceland pioneered techniques to halt land degradation and in restoration. And for more than 100 years the Soil Conservation Service has struggled but the gains are small and very slow in coming. Today at least half of the former forests and grasslands are mostly bare and subject to severe erosion by the strong winds.
“We’re still fighting overgrazing here,” Halldórsson said.
Iceland relies far less on agriculture now and the harsh lessons of poor land management of the past are irrelevant to the 90 percent of Icelanders who now live in urban areas.
“The public isn’t supporting land restoration. We’ve forgotten that land is the foundation of life,” Halldórsson said.
A timely story. Note story with similiar focus and discussion on Hot Topic. Good video too.
http://hot-topic.co.nz/the-answer-lies-in-the-soil-you-have-to-have-a-sense-of-humus/
'“It takes half a millennia to build two centimetres of living soil and only seconds to destroy it,” Glover said.'
In Iceland, I believe that statement, in Brazil or Indonesia?
I have no idea, perhaps this rate of soil growth of 0.04mm/yr IS constant everywhere on the planet but my spidey-sense says no. Anyone know for sure?
Putting more carbon into soil will improve the quality of the soil and should be done for that reason. However as a method of reducing CO2 in the atmosphere it makes little economic sense.
To keep organic carbon in the soil each extra ton of carbon must be accompanied by 80 Kg of nitrogen, 20 Kg of phosporous and 14 kg of sulphur which in Australia would have a total cost of about $250. Stubble generally contains small amounts of these nutrients ( with the exception of legume stubble which is relatively rich in Nitrogen) so they would have to be added in some other way.
This article by Stephen Leahy and copied here by John Hartz is showing ignorance of soil science. There is nothing here to read. Australia is a totally different soil science, and generalisations such as this are not useful to the climate debate. S/Wombat above... you don't have to keep carbon in the soil, just keep turning it over.
Please no more coments.
Boswarm,
Could you provide a citation to support your claims or do we have to rely on your uninformed opinion? Hand waving claims can be dismissed with a hand wave.
In my 1/2 acre orchard in Florida sand, I started mulching with oak leaves (almost pure carbon) three years ago to reduce weeds. My trees look much better now and I have a lot of earthworms, which were not there before. Soil chemistry is complex, but it is well known that soil is degraded in many locations where there have been farms for a long time. Look at the pictures of Iraq. They have farmed there for centuries and much of the country is now dessert.
Michael,
You have explained exactly what I said, SW is talking rubbish, have at look at CSIRO Soil Science papers to find proof as well as your own situation improving. I am not disagreeing with you, as you are doing the right things. It is the information that Stephen Leahy has left out that is crucial. JMO
Another good article on this subject here: 'Peak soil: industrial civilisation is on the verge of eating itself'
Boswarm, SkS is a fact-based site: as such, please ciyte the sources that support what is, at the moment and acknowledged in your own words [bolded], is just unsupported opinion.
"It is the information that Stephen Leahy has left out that is crucial. JMO"
Please be specific WRT what Leahy has "left out."
So, theoreticaly, which strategy would achieve the faster C sequestration rate? Forest restoration or soil restoration?
Restoration of the ancient forests would have drawn down 29% human C which is 600Gt (according to land use emission data). I have do idea how long it would take. A wild guess: say 200 y in most places (average mature tree age), so 3Gt/y? Anyone knows better numbers?
Compared to the quoted above pasture potential sequestration rate of 10 percent of the emissions (currently 10Gt), so 1Gt/y.
Even if feasible (needless to say realistic while feeding 6b+ population), it's still not enough to make good dent in the emissions, so cutting emissions themselves is the only option.
Could someone address how this fits with some of the work of "peak farmland". The idea that more efficient methods have lead to lower utilization of land for the same yields? One paper on this is at http://phe.rockefeller.edu/docs/PDR.SUPP%20Final%20Paper.pdf
The article sites overgrazing which has been the mantra for ages without going into the finer detail. Oddly enough, an extremely heavy grazing, if done correctly, can be not only extremely beneficial but totally necessary for soil recovery and carbon sequestration. Removing grazers on areas with seasonal rains causes desertification. Have a look at this TED talk by Allan Savory.
http://www.youtube.com/watch?v=pnNaLSKDf-0
To Panzerboy
In soils where the temperature is above 250C, soil carbon does not accumulate. Humus is broken down at these temperatures. There is a solution though. Charcoal can take the place of humus in tropical soils.
http://mtkass.blogspot.co.nz/2009/07/terra-preta-how-does-it-work.html
vrooomie at 02:40 AM on 17 June, 2013
I was going to let this go: "Boswarm, SkS is a fact-based site," that's exactly why I comented. SKS is the site I go to regularly to read. I love it.
But unfortunately you jump to conclusions. Iceland is probably the most advanced soil science farming group in the world today. Yes, the soil was degraded over centuries, yet the current group of agriculutral residents have taken Iceland back to relative normality within the toughest conditions on Earth. Have you been to Iceland?
The Farmers Association of Iceland is probably the world leader in soil science and data collection. Look up www.bondi.is and carefully see how the above report has omitted so much factual information. I think the author has not been dealing with the facts in the above report. The Farmers Association of Iceland are more aware of Climate Chnage than you or I.
It was just a comment meant to highlight how some communities are dealing with soil problems and SOLVING them, where as some are refusing to even acknowledge the problem at all eg: Australia. I don't think highlighting Iceland as a case to publicily state that it is close to PEAK SOIL is correct. It should have been titled "Back from the Brink". Too much has been left out, that's all.
You should have gone to the SOIL CARBON SEQEUSTRATION CONFERENCE in Reykjavík and listened to all of the presentations. Very different to the above in reporting on this important conference and it's meanings.
Anne Glover, European Commission – Carbon sequestration: Linking policy, science and action
Luca Montanarella, EC-Joint Research Centre - Global status of soil carbon
Rattan Lal, School of Environment & Natural Resources Ohio State University – Potential of soil carbon sequestration
Leena Finér, METLA, the Finnish Forest Research Institute – Soil and Water
Asger Strange Olesen, European Commission – Land use policy and action
Lars Vesterdal, University of Copenhagen – Carbon sequestration in forest soil
Ólafur Arnalds, The Agricultural University of Iceland – Carbon sequestration in revegetation and rangeland
Thomas Kätterer, Swedish University of Agricultural Sciences (SLU) – Carbon sequestration in cropland
Hlynur Óskarsson, The Agricultural University of Iceland – Carbon sequestration in wetland
A couple of observations...
In the Canadian prairies, the worst loss of topsoil from wind erosion was during the the dustbowl era of the 1930s. Farming practices such as methods of cultivation improved, and shelterbelts were planted, reducing topsoil loss through wind erosion. However the biggest improvement has been in the last couple of decades, with the widespread adoption of zero-till farming methods. ie. I don't think the picture is as bleak as this article portrays.
Also, the article mentioned worms. Earthworms in particular may be beneficial to certain soils, but are terrible for forest soils.
Boswarm: Since I was at the conference, attended the sessions, interviewed a dozen people and wrote the article let me clarify a couple of things: Iceland has not recovered, it remains Europe's largest desert despite the amazing efforts of the soil cons service. That is what their scientists told me and I quoted them. I spent 2 wks there.
You seem to imply I made this stuff up. Were you at the conf?
FYI It is a 1000 word article, not a transcript of 3 days of talks
Phil L: the article does not mention earthworms, it's in the photo cutline and have no idea who wrote it. Nor did I write the headline. However more than one soil scientist has used the term 'peak soil'.
Phil L: I see now the mention of earthworms as part of my general description of life in dirt.
Stephen Leahy: Peak Oil refers to a non-renewable resource. Oil will reach a peak eventually, but I believe that with good stewardship, the soil is truly sustainable. Certainly there are examples of soil degradation, but I think it's important to acknowledge where good farming practices are taking place. I know people who farm in England on land that has been farmed for centuries, using scientific principles of crop rotation, and their soil is probably in better condition than it was 200 years ago. I also remember driving through southern Saskatchewan in the 1980s when the air would be dusty as the wind blew topsoil off of the summerfallow. Now there is much less summerfallow because farmers have adopted zero-tillage practices, and the organic content of the soil is increasing. Bad farming practices should be criticized, but I also believe that good farming practices should be recognized and applauded.
And I don't question the value of earthworms in gardens or agricultural soil. It's the forest soils that suffer from earthworm introduction, as discussed in the article that I linked to.
Stephen Leahy,
I did not infer or imply you made this stuff up?
Read my comment again. It's the bits left out that got to me. Then you say:
"Iceland has not recovered, it remains Europe's largest desert despite the amazing efforts of the soil cons service. "
It has recovered and adapting to the new soil conditions, and as it warms, the position will improve. The statistics prove this. See the references in my previous coment especially www.bondi.is
"FYI It is a 1000 word article, not a transcript of 3 days of talks" - I know what you wrote, I have all the transcripts from the conference, yet so much was omitted in the true story of Iceland farming.
What these figures exhibit is a shift from dairy and sheep to other forms.
It's called adapting, not peak soil. Iceland is becoming one of the most unique farming communities in the world with now less than 6.5% of the population producing more agricultural and pastoral product than 77% of the population did in 1901. Change and adaption is what Iceland farmers are great at. If you visited the Westfjords you would have seen a great change from an old farming practices to the new.
Have a look at the constant change between agriculture and pastoral - it's called adaption.
Your article was a correct representation of the conference, but needed a lot of information regarding the true nature of the industry in Iceland to create balance.
I am sorry if I have upset you in my comments above and here. I have seen Iceland over many years, and it is improving greatly, except for the fact that the good farmers, agricultualists and pastoralists are aging and not been replaced. It should be retiltled - PEAK FARMER.
And if vrooomie had any manners like you have Stephen, he would have asked similar questions. We have to keep fighting to reduce the carbon pollution or we will all be at peak END.