Green Car Congress
About GCC Contact  RSS Subscribe Twitter headlines

« Toyota Publishes Restructured Sustainability Report | Main | Mercedes-Benz Launches Euro-5 BLUETEC in Europe »

Print this post

Conventional Plowing Is “Skinning Our Agricultural Fields”

10 August 2007

A new study published in the Proceedings of the National Academy of Sciences confirms the “long-articulated contention” that erosion rates from conventionally plowed agricultural fields average 1–2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion.

Author David Montgomery, University of Washington Professor of Earth and Space Sciences, looked at data from more than 1,650 measurements published in more than 200 studies examining various aspects of farming practices, soil creation and erosion.

We are skinning our agricultural fields. But there are methods of farming, no-till in particular, that don’t have to lead to that result. Soil loss through conventional agriculture is in a range of 10 to 100 times greater than the rate at which soil is created. No-till agriculture brings it into the ballpark, surprisingly close to being balanced with soil creation.

—David Montgomery

Long-term erosion rates worldwide average less than one-tenth of a millimeter per year, which is similar to the rate at which soil is produced through mechanical, chemical and biological processes that dissolve rock and mix the grains with organic matter. The research shows that erosion rates consistently exceed 1 millimeter a year—less than a half-inch per decade—only in steep alpine terrain. Plowed fields erode at about the same pace as the Himalayas, home to the highest mountain peaks in the world.

The paper supports arguments Montgomery put forth in a popular book, Dirt: The Erosion of Civilizations, published earlier this year by the University of California Press. In the book, he linked the demise of history’s major civilizations to how long it took them to deplete their soil supply.

In the case of civilizations past, when the soil wore out the people could move to other places and find rich enough soil to sustain them. But with the world population now exceeding 6.6 billion people, Montgomery argues that there are few, if any, places left where the soil can feed a large population for very long.

No-till agriculture does away with plowing, which often involves stripping crop stubble from fields before deeply turning the soil. Often a plowed field will be disked to remove stubble and weeds. No-till agriculture uses disking to turn only the top layer of soil. Some other methods, such as hand-tilling on terraced fields, also preserve the soil but are more labor intensive and so are not practical on a large scale, Montgomery said.

He noted that as oil becomes more expensive and less available, it will be even more important to preserve soil fertility through methods such as no-till farming, which requires less fertilizer and many fewer passes with a tractor.

No-till farming can build soil fertility even with intensive farming methods, he said, and it could prove to be a major benefit in a warming climate. By stirring crop residue into the soil surface, no-till farming can gradually increase organic matter in soil, as much as tripling its carbon content in less than 15 years.

Returning the organic matter to the soil stores carbon. If all farms on the planet were converted to no-till, the range of estimates for sequestered carbon runs from 10 percent of current carbon emissions to about half. It’s probably closer to 10 percent, but even that would be a significant benefit. It’s one of the few win-win options in trying to forestall the effects of climate change.

—David Montgomery

Resources:

August 10, 2007 in Sustainability | Permalink | Comments (11) | TrackBack (0)

Comments

well that's scary

Posted by: Brad | August 10, 2007 at 01:12 PM

Dear Sir:

I own/ operate a 2K commercial farm on the high plains and this article reflects the lack of knowledge that exists outside the working farm community and the swindle being laid on the naive/ unknowledgable people of the cities (Organic frequently means swindle).

That is not no-till. You are talking about minimum-till in which some of your conclusions are absolutely right about conservation. Your presentation reflects about one percent of the required knowledge to reflect the overall watershed conservation, level verse slightly roling soils, ridge no-till planting, and on & on.

You have mixed carbon sequester into this incorrectly. Mold-board plowing actually sequesters the most carbon into soil, but the unprotect soil lost to high plains wind or uncontrollable flooding before a protective cover crop is effective can not be tolerated.

Please establish/understand the 25 other factors involved with ag before generating documents that will be read by many more people without a clue of the overall picture.

This entire picture is so dymanic and interesting that I suggest that you continue this involvement with the same passion that many of us enjoy. The entire profession is frequently saturated with many uneducated operator/leaders that are in for the greed, naive heritage, continuing traditions that make no sense, some absolutely incompetent inplementation of new tech (ie. failure to rotate crops, herbicides, continuous roundup ready, GMO w/o impact analysis, farm integration of commerical livestock management, etc...)

Try developing a model of a high plains or further east farm community (let me and some others reflect on your model) and then start writing with the passion of the next 50 years of family farming. (Understand the evolution of people doing the farming and the nature of many who remain verse those who take college and professional careers in the city. I am a retired Chemical Engineer.)

Posted by: Wm Strasburg | August 11, 2007 at 09:13 AM

@ Wm Strasburg -

thx for your comment. Farmers do indeed have a long tradition of husbanding their primary resource, the fertility of their land. And as you make clear, that's a lot harder to do than most outside that industry will ever know.

Still, I expect market distortions such as European farm subsidies that were long based on production volume alone or, corn ethanol subsidies in the US, do skew the incentives. Farmers whose children show no interest in taking over the family business might decide to maximize their short-term profits rather than protect the soil. Eventually, they have to sell the land to a much larger corporation that may view it as a resource to be exploited rather than husbanded.

But back to green vehicles: does anyone know if minimum-till and similar philosophies save significant amount of tractor fuel compared to conventional practices?

Posted by: Rafael Seidl | August 11, 2007 at 12:51 PM

Wm. Strasburg,
I think the people here would be receptive to farmers input on this. I think though that lashing out at the writer of this article suggests that you might have a chip on your shoulder for reasons that go way beyond this issue.

For one, the article is simply relaying the findings of agricultural scientists who we all have assumed are experts in this matter. If you want to pick a fight with agricultural scientists please do so, but attack them directly with well founded arguments not by discounting the qualifications of the web journalists and web audience of this blog.

I am interested to hear about your characterization of organic as a "swindle". Please elaborate.

Posted by: Michael | August 11, 2007 at 01:56 PM

I come from farming stock.Small farming in Ireland and then in Tuscany,which I think qualifies me to speak on this. Shooting the messenger is always a bad tactic,and I agree that referring to organics as a swindle does suggest a certain agenda.
No-Till and Low-Till methods are part of the solution,and suitable for certain situations.
It should be obvious that what works in the high plains won't necessarily work in other situations.
I can report that this works; our big field was below a dirt road,which regularly washed down on it.It was covered in a layer of sand and gravel . We used goats first, then put pigs on it,and soon the land was clear enough to see.We put down straw and compost,leaf-mould from our small stand of trees. We brought seaweed from the beach and any manure we could find/afford.And we mulched like crazy to save water and to reduce weeding. The worms loved the mulch and we grew crops for the market niche we occupied.We found the system works
But it best suited to the small farmer,perhaps. Big Farming is less loving of the soil,which few of them have had under their finger nails. Remember there are a lot of small farmers all over the world,and anything which makes them more productive will surely be a good result,reducing famine risk. It may also involve us in a big change in thinking, and a new model of the world. Perhaps even learning from the ancient farming lore common amongst the locals.(This can be difficult if you have exterminated the previous owners.People get attached to land,and has led to an 800 year war where I live.)
However,green investors will be glad that soon the products will be made from non-food sources and avoid palm oil.

Posted by: wheelsofire | August 12, 2007 at 12:13 PM

Someone said:
"Modern agriculture is the use of soil to turn oil into food"

Posted by: | August 12, 2007 at 02:27 PM

Shades of Faulkner's "A PLOWMAN'S FOLLY" (1943) and "A SECOND LOOK" (1947).

As I understand it, farm subsidies in the US require low or no till methods, which until recently were extremely difficult for many to implement without the use of a product like MONSANTO's Roundup.

Intuitively, I want to disagree with the argument that moldboard plowing will sequester more carbon, but I need to give it more thought, as there are thousands of things happening in healthy soil.

Posted by: John Schreiber | August 13, 2007 at 05:30 AM

@ Raphael,
yes, there are energy savings with no till.

A site that I like with no till info is: http://www.newfarm.org/depts/notill/index.shtml

Posted by: John Schreiber | August 13, 2007 at 05:34 AM

I believe Strasburg in his comments, got heated up over the statement attributed to Montgomery: "No-till agriculture uses disking to turn only the top layer of soil."

Strasburg is correct in saying that this is "minimum-till, not no-till." His tone however made it difficult for some, including me, to see his point.

Posted by: John Schreiber | August 13, 2007 at 05:48 AM

I grew up on the plains of Alberts. During the thirties we ploughed the land every third year. The result; sandstorms carrying the ploughed fields away leaving a desert.

A farmer by the name of Noble develoed the rod weader which ran under the surface destroying the roots of weeds: mainly wild oats.

This was followed by the development of the one-way disc which left most of the trash on the surface.

Today the fields are no longer tilled. Grain is seeded with fertilizer with an injeator type seeder. Herbicides and pesticides are sprayed. Combine harvesting leaves all straw on the surface.

Studies show substantial CO2 sequestration. Non till farmers are expecting to augment their income with the sales of carbon credits.

Posted by: E. Keith Cumming | August 13, 2007 at 04:34 PM

Then plant switch grass and mow it to provide biomass for bio fuels. Soil preserved and problem solved.

Posted by: sjc | August 17, 2007 at 08:50 AM

Post a comment
[Please keep comments on topic. Disagreement is fine; insults, abuse or wild diversions are not. Comments not meeting those standards will be deleted. Abuse of another commenter’s email address will result in the banning of the offender from this site. In an attempt to prevent the posting of insulting and abusive comments, this site maintains a list of prohibited words and phrases, which, unfortunately, grows with time. Including one of the prohibited words or phrases will flag the comment as “spam”, and it will be blocked.]

Green Car Congress only allows comments from registered users. To comment, please Sign In.

TrackBack

TrackBack URL for this entry:
http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef00e39825b49f8833

Listed below are links to weblogs that reference Conventional Plowing Is “Skinning Our Agricultural Fields”:

Green Car Congress © 2009 BioAge Group, LLC. All Rights Reserved. | Home | BioAge Group