New research explores the impact of cover crop residues on weed control

April 23, 2020

WESTMINSTER, Colorado - April 23, 2020 - Cover crops have a well-documented role to play in suppressing troublesome weeds. But what happens as those cover crops degrade?

A new study featured in the journal Weed Science explores whether cover-crop residues help to suppress summer annual weeds and promote greater crop yields. Researchers planted single cover-crop treatments of cereal rye, hairy vetch, crimson clover and forage radish in the fall, as well as two-way and three-way mixtures. Each was followed by corn and soybean crops.

The team tracked the biomass of each cover crop and the residual components produced - uncovering several key trends. They found that cover-crop biomass and the ratio of carbon to nitrogen influenced weed suppression and its duration. For example, a 9 to 1 ratio of carbon to nitrogen suppressed pigweed by 50 percent at four weeks after treatment, while a 20 to 1 ratio delivered the same level of control eight weeks after treatment.

Similarly, a cover-crop biomass of 2,800 kg per hectare was needed for 50 percent suppression four weeks after treatment, while a biomass of 6,610 kg per hectare was needed for the same level of suppression at eight weeks after treatment.

In fields where the cover crop was the only weed control measure used, corn and soybean yields increased as both cover crop biomass and carbon to nitrogen ratios increased.

Researchers found that most mixtures of cover crops produced more biomass than individual cover crops alone. Carbon to nitrogen ratios produced by cereal rye and a cereal rye-forage radish mixture were 36 to 1 - greater than all the other cover crop treatments. Hairy vetch and crimson clover had ratios of 12 to 1 and 17 to 1, which were the lowest ratios produced by any of the cover crops.

"Our study shows that the biomass of the cover crop isn't all that matters," says Kara Pittman of Virginia Tech, lead researcher for the study. "The composition of the residues the cover crop leaves behind are also important to weed control."
-end-
To learn more, read the article "Cover Crop Residue Components and their Effect on Summer Annual Weed Suppression in Corn and Soybean" online.

About Weed Science

Weed Science is a journal of the Weed Science Society of America, a nonprofit scientific society focused on weeds and their impact on the environment. The publication presents peer-reviewed original research related to all aspects of weed science, including the biology, ecology, physiology, management and control of weeds. To learn more, visit http://www.wssa.net.

Cambridge University Press

Related Biomass Articles from Brightsurf:

Bound for the EU, American-made biomass checks the right boxes
A first-of-its-kind study published in the journal Scientific Reports finds that wood produced in the southeastern United States for the EU's renewable energy needs has a net positive effect on US forests--but that future industry expansion could warrant more research.

The highest heat-resistant plastic ever is developed from biomass
The use of biomass-derived plastics is one of the prime concerns to establish a sustainable society, which is incorporated as one of the Sustainable Development Goals.

Laser technology measures biomass in world's largest trees
Laser technology has been used to measure the volume and biomass of giant Californian redwood trees for the first time, records a new study by UCL researchers.

Inducing plasma in biomass could make biogas easier to produce
Producing biogas from the bacterial breakdown of biomass presents options for a greener energy future, but the complex composition of biomass comes with challenges.

Microbes working together multiply biomass conversion possibilities
Non-edible plants are a promising alternative to crude oil, but their heterogenous composition can be a challenge to producing high yields of useful products.

Evergreen idea turns biomass DNA into degradable materials
A Cornell-led collaboration is turning DNA from organic matter -- such as onions, fish and algae -- into biodegradable gels and plastics.

Upgrading biomass with selective surface-modified catalysts
Loading single platinum atoms on titanium dioxide promotes the conversion of a plant derivative into a potential biofuel.

A novel biofuel system for hydrogen production from biomass
A recent study, affiliated with South Korea's Ulsan National Institute of Science and Technology (UNIST) has presented a new biofuel system that uses lignin found in biomass for the production of hydrogen.

Biomass fuels can significantly mitigate global warming
'Every crop we tested had a very significant mitigation capacity despite being grown on very different soils and under natural climate variability,' says Dr.

Traditional biomass stoves shown to cause lung inflammation
Traditional stoves that burn biomass materials and are not properly ventilated, which are widely used in developing nations where cooking is done indoors, have been shown to significantly increase indoor levels of harmful PM2.5 (miniscule atmospheric particulates) and carbon monoxide (CO) and to stimulate biological processes that cause lung inflammation and may lead to chronic obstructive pulmonary disease (COPD), according to new research published online in the Annals of the American Thoracic Society.

Read More: Biomass News and Biomass Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.