USA
July 3, 2012

For more than a decade, consumer demand for organic products in the United States has seen double-digit growth. Organic foods now comprise more than 3 percent of U.S. food sales, and the amount of certified organic farmland is increasing as well. Yet demand still supports importation of organic products. A major limitation affecting domestic organic crop production is effective weed control.

The current issue of the journal Weed Technology discusses costs and difficulties of weed control in organic peanut. Field tests were conducted from 2008 to 2010 in the southeastern peanut-producing region of the United States. Implements and frequencies of cultivation needed to achieve the best organic crop results were tested.

Cultivation effectively eliminates weeds between crop rows. More difficult to manage are the weeds growing within the rows. The nature of the peanut plant, with its underground fruit, also limits how long and how aggressively cultivation can be applied. Hand weeding is often the solution, which adds labor costs to the organic crop.

In these field tests, researchers used a tine weeder, with multiple rows of flexible steel-rod tines, and a power take-off brush hoe, with rotating stiff brushes that scour the soil surface. These implements were applied to peanut patches at a variety of time periods, including the first emergence of vegetation, one week after emergence, two weeks after emergence, and combinations of emergence and one week later, emergence and two weeks later, and emergence and one and two weeks later.

The lesson learned from these trials was the earlier, the better. Cultivation was less effective when the initial application was delayed. Both implements performed best when used at emergence. The best combination of factors—leading to maximum peanut yield and requiring minimal hand weeding—was cultivating at both emergence and one week later, using either machine to perform a row middle sweep cultivation, and also including a preharvest mowing.
Hand weeding was required to control remaining weeds no matter what treatment was applied in these experiments. The objective became to find the combination of tool and frequency of cultivation that left behind the fewest weeds to be pulled by hand, thus reducing labor costs.

Full text of the article, “Implements and Cultivation Frequency to Improve In-Row Weed Control in Organic Peanut Production,” Weed Technology, Vol. 26, No. 2, 2012, is available at http://www.wssajournals.org/toc/wete/26/2.

Weed Technology presents (1) original research on weed/crop management systems, herbicides, weed resistance to herbicides, and weed biology; (2) reports of new weed problems, weed-related surveys, and new technologies for weed management; and (3) special articles emphasizing technology transfer to improve weed control. The journal is a publication of the Weed Science Society of America. To learn more about the society, please visit: http://www.wssa.net/.

Website: http://www.wssa.net

Published: July 3, 2012