Cover Crops May Help Solve Weed, Pest Problems


January 3, 2013
By Logan Hawkes 
Full Article 

In the ever-changing world of agriculture, technology often leads the way in providing the latest, most current developments in modern farming. But when it comes to weed management and pest control, a return to the roots of American farming may provide our best defense to these age-old problems.
In recent years, researchers at Sustainable Agriculture Research & Education (SARE) have been working with cover crops as one of the most effective ways to improve soil health and reduce off-farm inputs and protect natural resources. A series of project grants has focused on research that utilized various cover crops to mange weeds and pests with some rather remarkable results.
In one of the projects, Cornell University researchers have demonstrated that buckwheat is gaining new popularity as a powerful weed-suppressing cover crop because of its quick establishment and dense growth, effectively eliminating 98 percent of summer weeds at one vegetable farm. In all, Cornell had helped 3,000 farmers use buckwheat successfully on a combined 18,000 acres in vegetable production.
In another grant project, SARE helped University of Hawaii researchers demonstrate how sunn hemp as a cover crop in vegetables helped control weeds, nematodes and other pests, add soil nutrients, prevent erosion, and contribute to a more robust and complex community of beneficial nematodes.
In yet another SARE-funded project, growers, researchers, and Extension personnel plan to collaborate in university and on-farm trials in western, central, and southern Illinois to evaluate the efficacy and feasibility of using cover crops for disease suppression in soybeans. As a result, growers and the academic community will increase their knowledge of the use of four cover crops for suppressing soybean diseases, and they will better understand how cover crops can integrate with current production practices.
In addition to weed management and pest control, research in the use of cover crops is indicating additional benefits. In select field projects, cover crops illustrate their benefits in helping producers save soil, nutrients and money.
Oregon State University Extension specialists have spent six years studying the role cover crops play in fertility management. Already, this research project has helped develop a calculator for estimating the cost and nitrogen contribution of cover crops, compost, and organic and synthetic fertilizers. The calculator has been used repeatedly with great success since 2010 over an area encompassing more than 52,000 acres.
Researchers say the profit potential from cover crops’ role in nutrient management is immense. In one trial, the researchers found a vetch cover crop could replace 110 pounds per acre of feather meal for a vegetable crop, leading to a cost saving of $500 per acre.
Other projects
Other cover crop research projects supported by SARE include:
  • A 2003 project involving University of Maryland researchers and farmers showed that forage radish can capture and hold up to 150 pounds of nitrogen per acre that remains in the soil after fall harvest. This work also helped lead to the widespread adoption of forage radish as a powerful method for alleviating soil compaction.
  • In 2008, an Ohio State University graduate student found compelling evidence of cover crops’ role in protecting soil from erosion, and water from nutrient leaching. During simulated rainstorms, cover crops and no-till in a corn-soybean rotation nearly eliminated runoff loss of soluble nitrogen and phosphorous.
  • An ongoing project at North Carolina State University is finding evidence that the termination method for leguminous cover crops affects how much nitrogen is made available to the subsequent cash crop. Roll-killed hairy vetch provided more available nitrogen six weeks after termination than other combinations of legumes and kill methods, including herbicides, flail mowing and tilling.
SARE researchers say while most grants over the last 25 years have focused on vegetable farming projects, many of the same principles employed by cover crops in vegetable production apply to commodity crops as well. They suggest that in a world where technology leads the way in providing new methods for modern agriculture, producers would do well to look to historical methods of sustainable agriculture in addressing age old problems facing growers in the modern world.