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United States Department of Agriculture

Agricultural Research Service

Research Project: Conservation Systems Research for Improving Evnironmental Quality and Producer Profitability

Location: National Soil Dynamics Laboratory

Title: Intergrated palmer amaranth management in glufosinate-resistant cotton: I. Soil-inversion, high-residue cover crops and herbicide regimes

Authors
item Aulakh, J -
item Price, Andrew
item Enloe, S -
item Van Santen, E -
item Wehtje, G -
item Patterson, M -

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 24, 2012
Publication Date: November 5, 2012
Repository URL: http://handle.nal.usda.gov/10113/56852
Citation: Aulakh, J.S., Price, A.J., Enloe, S.F., Van Santen, E., Wehtje, G., Patterson, M. 2012. Intergrated palmer amaranth management in glufosinate-resistant cotton: I. Soil-inversion, high-residue cover crops and herbicide regimes. Agronomy. 2:295-311.

Interpretive Summary: Amaranthus control in cotton can be difficult with the loss of glyphosate efficacy, especially in conservation tillage cropping systems. Research was conducted to determine the level of glyphosate susceptible amaranthus control provided by four initial tillage and herbicide treatments including 1) moldboard plowing followed by a single pass disking and field cultivation plus pendimethalin at 1.2 kg ai ha-1 preplant incorporation (PPI), 2) two pass disking followed by field cultivation plus pendimethalin at 1.2 kg/ha-1 PPI, 3) a conservation tillage including an application of pendimethalin at 1.2 kg ai ha-1 preemergence (PRE) or 4) a non-treated conservation tillage control. Initial tillage operations including inversion with disking or disking twice resulted in pigweed density of = 4 plants m2 and 47 to 82% control while conservation tillage treatments had = 4 plants m2 and 14 to 62% control. Subsequent applications of PRE herbicides provided 53 to 98% and reduced Amaranthus density over no PRE to = 2 plants m2 regardless of tillage treatment. Results indicate that a one-time tillage operation followed by a return to conservation tillage may aid in the reduction of Amaranthus density when used with PRE applied herbicides; however, this system will likely not provide adequate control when high population densities of glyphosate resistance Amaranthus is present thus highlighting the need for a highly efficacious postemergence herbicide system.

Technical Abstract: Amaranthus control in cotton can be difficult with the loss of glyphosate efficacy, especially in conservation tillage cropping systems. Research was conduction from 2006 to 2008 at EV Smith Research Center, Shorter, Alabama, to determine the level of glyphosate susceptible amaranthus control provided by four initial tillage and herbicide treatments including 1) moldboard plowing followed by a single pass disking and field cultivation plus pendimethalin at 1.2 kg ai ha-1 preplant incorporation (PPI), 2) two pass disking followed by field cultivation plus pendimethalin at 1.2 kg/ha-1 PPI, 3) a conservation tillage including an application of pendimethalin at 1.2 kg ai ha-1 preemergence (PRE) or 4) a non-treated conservation tillage control in 2006; no further tillage practices were conducted after study initiation. Initial tillage operations including inversion with disking or disking twice resulted in Amaranthus density of = 4 plants m2 and 47 to 82% control while conservation tillage treatments had = 4 plants m2 and 14 to 62% control. Subsequent applications of PRE herbicides included pendimethalin at 1.2 kg ai ha-1 PRE plus fluometuron at 1.68 kg ai ha-1 or prometryn at 1.12 kg ai ha-1 provided 53 to 98% and 55 to 93%, respectively, and reduced Amaranthus density over no PRE to = 2 plants m2 regardless of tillage treatment. A postemergence (POST) application treatment of glyphosate at 1.0 kg ae ha-1 improved control in conjunction with almost all treatments in each year. Results indicate that a one-time tillage operation followed by a return to conservation tillage may aid in the reduction of Amaranthus density when used with PRE applied herbicides; however, this system will likely not provide adequate control when high population densities of glyphosate resistance Amaranthus is present thus highlighting the need for a highly efficacious postemergence herbicide system.

Last Modified: 8/29/2014
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