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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #205979
Title: Potential Weed Management Systems for Organic Peanut Production

Author
item Johnson, Wiley - Carroll
item MULLINIX, JR, BENJAMIN - UNIV OF GA, TIFTON,GA

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2007
Publication Date: 5/7/2008
Citation: Johnson, W.C., Mullinix, Jr., B.G. 2008. Potential weed management systems for organic peanut production. Peanut Science. 35:67-72.

Interpretive Summary: There is increasing demand for organic peanut and currently demand exceeds supply. To meet the increasing demand, conventional peanut growers in the southeastern U. S. are interested in diversifying into certified organic peanut production. Weed control is widely considered to be a limiting factor. Studies were conducted in Tifton, GA to develop weed management systems for organic peanut production. Trials in conventional tillage production systems evaluated row patterns, cultivation, and remedial weed management using propane flaming, clove oil extract, and citric + acetic acid. Trials were conducted in sites with extraordinarily heavy weed densities due to weedy-fallow crop history. Southern crabgrass, Texas panicum, and crowfootgrass were not adequately controlled by any of the treatments evaluated. Pitted morningglory, Florida beggarweed, and smallflower morningglory were initially controlled by propane flaming and clove oil extract, but the lack of residual weed control allowed subsequent weed emergence. Peanut yields were very low in all plots, primarily due to poor control of annual grasses. Results from these trials clearly show that weed control in organic peanut production will be difficult and costly. Organic peanut production should not be attempted in fields with a recent history of weedy-fallow.

Technical Abstract: Studies were conducted in Tifton, GA to develop weed management systems for organic peanut production. Trials in 2004 and 2005 evaluated row patterns (two levels), remedial weed control (four levels), and cultivation (three levels). Row patterns were wide rows and narrow rows. Remedial weed control was early-season applications of clove oil extract, citric acid + acetic acid, broadcast propane flaming, and a nontreated control. Cultivation regimes were sweep cultivation 1X, 2X, and a non-cultivated control. The experimental sites had heavy natural infestations of annual grasses and broadleaf weeds. None of the treatment combinations effectively controlled weeds season-long and resulting peanut yields were very poor. Annual grasses were particularly troublesome due to poor efficacy from propane flaming and citric + acetic acid. Clove oil extract was slightly more effective in controlling annual grasses than the other remedial treatments, but annual grass control was still unacceptable. Dicot weeds were not effectively controlled by mid-season, although clove oil extract and propane flaming controlled the seedling weeds early season. The lack of residual weed control by the remedial weed control treatments resulted in heavy weed infestations by mid-season. Poor control of annual grasses, no residual weed control, and high cost of remedial treatments indicates that these systems of weed management in organic peanut production are poorly suited to sites with heavy weed infestations.