An agricultural field in Ontario. A new Canadian study shows that as crop fields thaw in spring, they release previously unrealized quantities of a powerful greenhouse gas.
Photo Credit: Brendan Byrne, via CBC

Northern climate farm fields: an unexpected source of greenhouse gas

A Canadian farm field in spring as the snow melts may look present a tranquil picture, but there’s something dramatic taking place unseen to our eyes.

A new study in Canada found a surprising level of nitrous oxide emissions from thawing crop fields, a figure that has been greatly underestimated by climate researchers.

Claudia Wagner Riddle (PhD) is lead author of the study and a professor at the School of Environmental Sciences, University of Guelph, Ontario.

Listen
Claudia Wager Riddle (PhD) University of Guelph, Ontario © supplied

Nitrous oxide,sometimes known as “laughing gas”, is a common anaesthetic used in various medical and dental applications. Car racers such as dragsters also use nitrous to boost horsepower.

But it’s a powerful greenhouse gas which contributes to global warming and a changing climate, and it also destroys the ozone layer.

Nitrous oxide (N2O)makes up only a small portion of greenhouse gasses, but while carbon dioxide is the main culprit, on a molecular level,  N2O has about 300 times the absorption effect of CO2.  In other words While a single methane molecule has the effect of about 30 carbon dioxide molecules, one nitrous oxide molecule has the effect of 300 CO2 molucules

’Monitoring equipment over thawing field at Glenlea, University of Manitoba research station’.
Monitoring equipment over a thawing field at Glenlea, University of Manitoba research station. Measurements were recorded every 30 minutes for several years © Mario Tenuta

The result of a nine year study at  field locations in Manitoba and 14 years in crop fields in Ontario, the study examined data from 11 cold climate sites from around the world.

What the study found is that in northern climates such as across Canada, northern USA, northern Europe, and China, the nutrients in the soil along with inorganic nitrogen fertilizer are released in spring thaws. This results in a burst of activity from micro-organisms which releases in turn, bursts of N20.

Air sampling intakes for monitoring of nitrous oxide emissions over winter in a corn field in Ontario, Sites were monitored in the differing climates of Ontario and Manitoba, along with data from other northern climate sites around the world © Selma Maggiotto;

The study lead by Wagner-Riddle with collaborators from the University of Manitoba was published in Nature Geoscience under the title: “Globally important nitrous oxide emissions from croplands induced by freeze–thaw cycles (abstract HERE)

Previously such emissions from farm fields were only sporadically studied, but this comprehensive study shows that N20 from fields is much greater than estimated by climate modellers.  Because of that, climate scientists may be underestimating N2O emissions from agriculture by anywhere from 17 to 28%, a substantial amount.

While this process does occur naturally in wild fields and forests, with agriculture and the heavy and continual use of nitrogen fertilizers, the release becomes far greater.

The Canadian research also found that the colder the winter, and the longer soil was frozen, the greater the release of nitrous oxide.

Wagner-Riddle says farmers can reduce their contribution to greenhouse gasses by leaving cover on the fields over winter which captures snow and helps reduce the depth and duration of frozen soil. Another method is to avoid tillage and plant directly into the soil.

The soil in this field in Prince Edward Island is protected for the winter with a cover crop of oats, planted this fall. The plants help capture snow which acts as an insulator reducing the depth of freezing into the soil, one method of reducing N2O emmissions in spring © (Brian Higgins/CBC

She says while there was always a natural amount of N20 emissions, with our modern farming practices humans are clearly affecting and greatly increasing the nitrogen cycle.

additional information

Tagged with: , , ,
Posted in Environment, International, Science and Technology, Work & Labour

Do you want to report an error or a typo? Click here!

@*@ Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

 characters available

Note: By submitting your comments, you acknowledge that Radio Canada International has the right to reproduce, broadcast and publicize those comments or any part thereof in any manner whatsoever. Radio Canada International does not endorse any of the views posted. Your comments will be pre-moderated and published if they meet netiquette guidelines.

Netiquette »

When you express your personal opinion in an online forum, you must be as courteous as if you were speaking with someone face-to-face. Insults and personal attacks will not be tolerated. To disagree with an opinion, an idea or an event is one thing, but to show disrespect for other people is quite another. Great minds don’t always think alike—and that’s precisely what makes online dialogue so interesting and valuable.

Netiquette is the set of rules of conduct governing how you should behave when communicating via the Internet. Before you post a message to a blog or forum, it’s important to read and understand these rules. Otherwise, you may be banned from posting.

  1. RCInet.ca’s online forums are not anonymous. Users must register, and give their full name and place of residence, which are displayed alongside each of their comments. RCInet.ca reserves the right not to publish comments if there is any doubt as to the identity of their author.
  2. Assuming the identity of another person with intent to mislead or cause harm is a serious infraction that may result in the offender being banned.
  3. RCInet.ca’s online forums are open to everyone, without regard to age, ethnic origin, religion, gender or sexual orientation.
  4. Comments that are defamatory, hateful, racist, xenophobic, sexist, or that disparage an ethnic origin, religious affiliation or age group will not be published.
  5. In online speak, writing in ALL CAPS is considered yelling, and may be interpreted as aggressive behaviour, which is unpleasant for the people reading. Any message containing one or more words in all caps (except for initialisms and acronyms) will be rejected, as will any message containing one or more words in bold, italic or underlined characters.
  6. Use of vulgar, obscene or objectionable language is prohibited. Forums are public places and your comments could offend some users. People who use inappropriate language will be banned.
  7. Mutual respect is essential among users. Insulting, threatening or harassing another user is prohibited. You can express your disagreement with an idea without attacking anyone.
  8. Exchanging arguments and opposing views is a key component of healthy debate, but it should not turn into a dialogue or private discussion between two users who address each other without regard for the other participants. Messages of this type will not be posted.
  9. Radio Canada International publishes contents in five languages. The language used in the forums has to be the same as the contents we publish. The usage of other languages, with the exception of some words, is forbidden. Messages that are off-topic will not be published.
  10. Making repetitive posts disrupts the flow of discussions and will not be tolerated.
  11. Adding images or any other type of file to comments is forbidden. Including hyperlinks to other websites is allowed, as long as they comply with netiquette. Radio Canada International  is in no way responsible for the content of such sites, however.
  12. Copying and pasting text written by someone else, even if you credit the author, is unacceptable if that text makes up the majority of your comment.
  13. Posting any type of advertising or call to action, in any form, to Radio Canada International  forums is prohibited.
  14. All comments and other types of content are moderated before publication. Radio Canada International  reserves the right to refuse any comment for publication.
  15. Radio Canada International  reserves the right to close a forum at any time, without notice.
  16. Radio Canada International  reserves the right to amend this code of conduct (netiquette) at any time, without notice.
  17. By participating in its online forums, you allow Radio Canada International to publish your comments on the web for an indefinite time. This also implies that these messages will be indexed by Internet search engines.
  18. Radio Canada International has no obligation to remove your messages from the web if one day you request it. We invite you to carefully consider your comments and the consequences of their posting.

*