|CULPEPPER, S - University Of Georgia|
|KELTON, J - Auburn University|
|NICHOLS, R - Cotton, Inc|
|BURMESTER, CHARLES - Auburn University|
Submitted to: World Congress on Conservation Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2014
Publication Date: 7/7/2014
Citation: Price, A.J., Balkcom, K.S., Culpepper, S.A., Kelton, J.A., Nichols, R.L., Burmester, C.H., Schomberg, H.H. 2014. Glyphosate resistant weeds - a threat to conservation agriculture. World Congress on Conservation Agriculture, June 23-25, 2014, Winnepeg, Canada. p. 3-4.
Technical Abstract: Glyphosate-resistant weeds are now present throughout the Southeast. Hundreds of thousands of conservation tillage cotton acres, some currently under USDA Natural Resources Conservation Service (NRCS) conservation program contracts, are at risk of being converted to higher-intensity tillage systems. The shift to higher-intensity tillage facilitates burial of small weed seed as well as use of preplant incorporated herbicides for control of problematic weeds, especially in dry-land cotton production. In conservation tillage systems, a heavy residue cover crop like rye can help reduce the emergence of glyphosate-resistant weeds by suppressing weed germination and growth. When the winter cover crop is planted early and managed for maximum growth, a dense mat is formed on the soil surface. In addition, conservation tillage systems that minimize soil disturbance (direct seeding or minimum tillage) can help reduce seed germination. Since weed emergence and growth are suppressed by the physical barrier and shading of the residue, more residue results in better weed control. Depending on the severity of the glyphosate-resistant weed infestation, multiple strategies involving integration of cultural as well as chemical weed control will be needed to overcome this threat. Integrating high-residue cover crop systems may help facilitate weed control in row middles; however, weeds emerging in the crop row remain a threat to crop performance, especially in dry land cotton. Much research is needed to solve this threat to conservation tillage production.