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USA Rice Federation Daily, 3-18
Lincoln Announces $4.5 Billion Nutrition Legislation (Read More)

Diesel and gas prices up for fourth straight week
Diesel average price increases 2 cents a gallon nationally (Read More)

K. Good Farm Policy 3-18
Budget; Climate; Biofuels; Ag Econ; Food Safety; and Animal Ag (Read More)

Texas: What is rain harvesting?
Course scheduled, Kerrville, April 12-13 (Read More)

K. Good's Farm Policy, 3-17
Budget; Climate; Ag Economy; Trade; Biofuels; and Crop Insurance (Read More)

K. Good's Farm Policy, 3-16
Climate; Trade; Ag Economy; Corn Production (Read More)

Rice Advocate, 3-12
Rice farmers speak out against current U.S. policy toward Cuba (Read More)

K.Good's Farm Policy News, 3-12
Trade; Climate; Ag Competition; Animal Ag (Read More)

K.Good's Farm Policy News, 3-11
Jobs Bill; Insurance- SURE; Competition; Climate; and Trade (Read More)

Hurricanes: AccuWeather Calls For More Active 2010 Season
Expect a 2010 hurricane season more like the one in 2008 than 2009. (Read More)

Diesel, gasoline prices up yet another week, 86 cents above year-ago price
Average U.S. diesel price running 86 cents a gallon above same period a year ago. (Read More)

K.Good's Farm Policy News, 3-10
FAPRI; Biofuels; Disaster Payment; Climate Change; Farm Bill; Trade. (Read More)

Fight That Urge To Plant Into Vegetation - AMS Ag Report, E-Central Louisiana
How does the lineup of rice herbicides really compare to other crops? (Read More)

Rice Advocate, 3-5
Cuban Trade and Travel, H.R. 4645 (Read More)

Bayer Cuts Ignite Price
Also ramps up production. (Read More)

Arkansas: Rice Research News,3-3
"Roy J" is new high-yield and lodge resistant variety (Read More)

Diesel prices up 3 cents a gallon, 3-3
Gas prices also continue to increase (Read More)

Rice Advocate, 2-26
Producers Applaud Introduction of Cuba Trade and Travel Bill (Read More)

East-Central Louisiana 2010 Burndown And Planting Lags
Ruts remain a major issue for rice farmers (Read More)

Center for Agricultural Law and Taxation (CALT), 2-8
The Death (for the moment) of the Federal Estate Tax. (Read More)

Center for Agricultural Law and Taxation (CALT), 2-9
Top Ten Agricultural Law Developments of 2009 (Read More)

Mississippi Field Notes (Central Miss.), 2-8
Make sure your planting seed are good.| (Read More)

Texas Rice, Winter 2009
Cold Tolerance at Germination and Seedling Stages in Rice. (Read More)

Rice Industry Fears Job Losses, Economic Fall-Out from Ag Budget, 2-3
Farmers Applaud Sen. Blanche Lincoln, Other Ag Leaders for Opposing Plan (Read More)

EXCEL: The Louisiana: Projected 2010 Rice Farm Cash Flow Model
A Rice Production Farm Income and Expense Producer Decision Tool (Read More)

MANUAL: The Louisiana: Projected 2010 Rice Farm Cash Flow Model
PDF file with instructions for using the Excel spread sheet planner (Read More)

Louisiana: Rice Research Station News, 1-29
Two New Clearfield Varieties for 2010; Scout for Blast Early in the Season; White Tip Nematode; Comparison of Cruiser and Dermacor Seed Treatments; Blackbird Baiting Program. (Read More)

Diesel prices drop for second week in a row
National average down 4 cents, less in Gulf states and California (Read More)

Liberty-Link Traits Not Found In 2009 U.S. Rice Crop
Contamination cost sales, disrupted trade (Read More)

Louisiana: Projected 2010 Rice Farm Cash Flow Model, 1-25
A Rice Production Farm Income and Expense Producer Decision Tool. (Read More)

Soybeans still in the field? Look at them as a cover crop.|
Mississippi Field Notes (Central Miss.), 1-24 (Read More)

Tractor sales will remain weak in 2010, says association
Lower commodity and farm income numbers continue to depress buying enthusiasm (Read More)

10 Questions And Answers About Liberty-Link Soybeans
Overview from Georgia about where they fit with Roundup resistance in Palmer pigweed (Read More)

Rice Advocate, 1-15
USDA Proposes Cuts to Crop Insurance in SRA Negotiations. (Read More)

Resistent Weeds in the Future:

Harder to Kill in Soybeans, Rice, Corn, Wheat

AgFax.Com - Your Online Ag News Source

November 10, 2009– Poison ivy is thriving and becoming more toxic. And, that's just the tip of the proverbial iceberg. Agricultural Research Service (ARS) plant physiologists have found that environmental changes may produce "super resilient weeds" when linked with GMO crops.

Lewis Ziska, with the Crop Systems and Global Change Laboratory (CSGCL), found that because of increased carbon dioxide (CO2) levels in the atmosphere other weeds are also ramping up production. “We need to know how these atmospheric shifts will affect our ability to feed people around the world,” says Ziska.

Ziska is part of a team of ARS plant physiologists, including cooperators in Arkansas, who are studying how global climate change could affect food crop production and prompt the evolution of even more resilient weeds. Ziska, Richard Sicher and Jim Bunce all work at the ARS CSGCL laboratory in Beltsville, Maryland.

The ARS team conducted research on food crops, including soybeans, rice, corn and wheat, to learn more about how rising temperatures and rising carbon dioxide (CO2) levels could change production dynamics and crop yields.


In a typical production year, almost all the soybeans planted in the United States are genetically modified to resist herbicides. This allows farmers to eradicate weeds in soybean fields without harming their crops.

Ziska found that with typical precipitation levels, growth of genetically modified, glyphosate-resistant soybeans is stimulated by elevated CO2 levels—but so is the growth of weeds that are typically kept in check by the herbicide. So producers may need new strategies for managing soybean weeds as CO2 levels rise.

“Increased CO2 for most crops is a positive,” says Sicher. “You can double CO2 and almost anything will grow. The detrimental changes can be more subtle.”


Anna McClung, research leader at the ARS Dale Bumpers National Rice Research Center at Stuttgart, worked with the ARS researchers to study rice. They collaborated to assess how strains of cultivated and wild red rice respond to elevated CO2. A weedy relative of cultivated rice, red rice can constrain production of rice grown for food.

The scientists found that elevated CO2 levels increased growth in both types of rice but more so in red rice. Significant differences in the rates and amount of growth were visible just 27 days after the seeds were planted. These growth differences indicate that, as CO2 levels increase, so too might competition between wild and cultivated rice. One way of preventing this would be for breeders to identify genetic traits in wild rice that support increased growth and breed these traits into cultivated varieties.

Ziska also partnered with scientists in China and concluded that when there was enough nitrogen in the soil to support growth, cultivated rice production was enhanced by rising CO2 levels. But when soil nitrogen levels were low, barnyardgrass—a common weed in paddy rice—was able to thrive at the expense of cultivated rice.


Studies on corn suggest that the higher levels of CO2 do not stimulate growth. But as CO2 levels rise, so do air temperatures. The warmer conditions prompt leaves to develop earlier and slow down leaf expansion, so above-ground biomass accumulation in the corn plant is suppressed.

Other work by the scientists shows that cheatgrass and Canada thistle--which are both aggressive and invasive weeds--flourish when CO2 levels rise, and that some varieties of dandelions have the genetic ability to adapt rapidly to rising CO2 levels. On the other hand, the same variability in dandelions and other weeds that facilitates rapid adaptation to global climate change might provide genetic material that could be used to breed cultivated crops with improved vigor and yield.

This kind of information could help farmers and policymakers develop more nuanced strategies for dealing with climate change.

A 3-year field study examined the comparison of modern wheat line Oxen sensitivity to rising CO2 levels of Marquis, a wheat line widely cultivated in the first half of the 20th century. Ziska believes these findings indicate that the ability of different wheat lines to respond to CO2 may depend on how the plants process the additional carbon.

Studies that Sicher and Bunce conducted on wheat indicate that it matures earlier when CO2 levels are elevated. Although elevated CO2 treatments can increase yields depending on the variety, a shorter growing season is known to reduce wheat’s yield potential. Wheat yields are also expected to fall as ambient temperatures increase.

“It’s a double whammy for wheat,” Sicher notes.

What About Weeds?

Ziska has also collaborated on work showing that cheatgrass and Canada thistle flourish when CO2 levels rise. Cheatgrass is an invasive annual that has become a major headache for rangeland managers in the western United States because it fuels wildfires and outcompetes native grasses. Canada thistle is an aggressive perennial weed that reduces forage consumption by cattle in pastures and rangeland.

Weeds in the wild have acquired a diverse genetic pool that helps them adapt to environmental challenges such as pests, disease, or extreme weather conditions. For these plants, global climate change is just another evolutionary contest.

“The greater range of responses observed for weeds in increasing atmospheric CO2 and temperatures may be related to their greater genetic diversity relative to crops,” Ziska explains. “In other words, the greater the gene pool, the more likely it is for a species to respond to a rapid environmental change.”