Featured Research

from universities, journals, and other organizations

Crop performance matters when evaluating greenhouse gas emissions

Date:
September 6, 2011
Source:
American Society of Agronomy
Summary:
A new study reports that total emissions of the greenhouse gas, nitrous oxide, were not significantly affected by tillage practices when expressed on an area basis. When they were calculated per unit yield of grain, however, emissions were significantly greater under no-tillage compared with conventional tillage.

Measuring the emission of greenhouse gases from croplands should take into account the crops themselves.

That's the conclusion of a study in the Sept.-Oct. issue of the Journal of Environmental Quality, which examined the impact of farm practices such as tillage on the greenhouse gas, nitrous oxide. Expressing emissions per unit of crop yield rather than on a more conventional per area basis produced very different results, says the study's leader, Rod Venterea, research soil scientist with the United States Department of Agriculture's Agricultural Research Service.

In particular, his team found that total nitrous oxide emissions were not significantly affected by tillage practices when expressed on an area basis. When they were calculated per unit yield of grain, however, emissions were significantly greater under no-tillage compared with conventional tillage. A byproduct of many agricultural systems, nitrous oxide is a potent greenhouse gas (GHG) with a heat-trapping potential more than 300 times that of carbon dioxide.

The findings have important implications for how the greenhouse gases generated by agriculture are reported, evaluated, and potentially mitigated. Nitrous oxide emissions were slighter higher under no-till on a per area basis in the study, Venterea explains, but not high enough to differ statistically from those under conventional tillage. "But when we added in the fact that no-tillage also reduced yields, the effect of tillage did become significant," he says. "The point is that you need to look at both nitrous oxide emissions and yield together."

While previous studies have shown that practices like fertilizer and tillage management can affect nitrous oxide emissions, relatively few have reported the effects of these practices on crop performance at the same time. In addition, GHG emissions are commonly expressed with respect to area of field: for example, kilogram nitrous oxide emitted per hectare. Recent research has suggested that expressing GHG emissions per unit of yield may be more meaningful, although few studies have actually done that.

To see how yield-scaled calculations might change the picture on emissions, USDA-ARS researchers in collaboration with University of Minnesota colleagues measured the effects of tillage and nitrogen (N) fertilizer management on nitrous oxide emissions, grain yields, and crop N uptake over three consecutive growing seasons in Minnesota. The experiment was conducted in research plots used for corn and soybean production, which were maintained under either no-till or conventional tillage for 18 years.

When the scientists calculated nitrous oxide emissions per unit yield of grain or grain N, they found that emissions under no-tillage were 52 and 66% higher, respectively, than with conventional tillage. In other words, for this cropping system and climate, Venterea says, no-till practices would generate substantially more nitrous oxide than would conventional tillage for the same amount of grain. The effect was due to lower yields under no-till, combined with slightly greater area-scaled nitrous oxide emissions.

Reduced yields under continuous no-till management in parts of the upper Midwest and other regions have been attributed to lower soil temperatures in spring, which may inhibit plant development. In other geographic regions, though, no-till can actually increase yields.

"So, for these other regions, expressing GHG emissions on a yield-basis could reveal benefits to no-till management that otherwise might not be quantified," Venterea says.

The study was funded by the USDA National Institute for Food and Agriculture (NIFA) and the Foundation for Agronomic Research.


Story Source:

The above story is based on materials provided by American Society of Agronomy. Note: Materials may be edited for content and length.


Journal Reference:

  1. Rodney T. Venterea, Maharjan Bijesh, Michael S. Dolan. Fertilizer Source and Tillage Effects on Yield-Scaled Nitrous Oxide Emissions in a Corn Cropping System. Journal of Environment Quality, 2011; 40 (5): 1521 DOI: 10.2134/jeq2011.0039

Cite This Page:

American Society of Agronomy. "Crop performance matters when evaluating greenhouse gas emissions." ScienceDaily. ScienceDaily, 6 September 2011. <www.sciencedaily.com/releases/2011/09/110906085420.htm>.
American Society of Agronomy. (2011, September 6). Crop performance matters when evaluating greenhouse gas emissions. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2011/09/110906085420.htm
American Society of Agronomy. "Crop performance matters when evaluating greenhouse gas emissions." ScienceDaily. www.sciencedaily.com/releases/2011/09/110906085420.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins