Author
|
Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only Publication Acceptance Date: 11/8/2003 Publication Date: 1/26/2004 Citation: Johnson, III, W.C. 2004. The non-chemical weed control research program in Georgia: The Good, The Bad, The Ugly [abstract]. Proceedings of the Southern Weed Science Society. 57:376. Interpretive Summary: Technical Abstract: Weed management in organic crop production systems requires an integration of cultural and mechanical controls, augmented with thermal and biological tactics. Successful weed control depends on careful integration of these tactics, tailored to the crop, weed species composition, and tillage system. Unfortunately, there is little research information on non-chemical weed control on crops grown in the southeastern coastal plain. Therefore, research projects were initiated in 2003 to evaluate nonchemical weed controls in leguminous vegetables, peanut, and turnip green. Solarization is a proven means of weed control in regions of intense solarization, i.e. the Middle East. In these regions, sunlight is intense enough to heat soil covered by clear plastic to temperatures lethal to weed seed and other propagules. Previous research in the southeastern U. S. has shown unsatisfactory weed control by short-term solarization. It is hypothesized that sacrificing the use of field for an entire summer for solarization and repeated fallow tillage may help reduce densities of yellow nutsedge in future crops. Therefore, trials were initiated in Tifton, GA in 2003 to determine if combinations of summer solarization and frequent fallow tillage deplete populations of yellow nutsedge and provide acceptable non-chemical weed control in fall seeded turnip green. This trial was conducted in a field with a heavy infestation of yellow nutsedge (>50 plants/m2). Treatments included all possible combinations of solarization (beginning in May, July, September, and nonsolarized) and frequency of shallow tillage (weekly, monthly, and nontilled). Plots were solarized using clear plastic, spread over moist clean seedbeds at the designated times and remained covered for the duration of the summer. Plots were shallow tilled to a depth of 7.6 cm at the appropriate times using a power tiller. Preliminary data analysis showed that weekly tillage and solarization beginning in May reduced the number of yellow nutsedge tubers in the soil and numbers of yellow nutsedge plants in direct seeded turnip green compared to the nontilled and nonsolarized controls. The preliminary analysis of these data suggests that densities of troublesome weeds may be reduced by summer solarization and tillage, which can be useful in organic cropping systems. Trials were initiated in 2003 to evaluate systems of weed management in peanut using propane flaming. Propane flaming provided acceptable control of small broadleaf weeds, however annual grasses were not controlled. Peanut was very tolerant to over-the-top propane flaming. These preliminary studies show that propane flaming is not a stand-alone practice for non-chemical weed control in peanut due to poor control of annual grasses, but offers potential when carefully integrated with other strategies. |
