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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #303068
Title: Integrated palmer amaranth management in glufosinate-resistant cotton

Author
item Price, Andrew
item AULAKH, J - Auburn University
item ENLOE, S - Auburn University

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2014
Publication Date: 2/21/2014
Citation: Price, A.J., Aulakh, J.S., Enloe, S.F. 2014. Integrated palmer amaranth management in glufosinate-resistant cotton. Weed Science Society of America Meeting Abstracts. CDROM.

Interpretive Summary:

Technical Abstract: Two separate three year field experiments were conducted to evaluate: 1) the role of soil-inversion, cover crops and herbicide regimes for Amaranthus palmeri between-row (BR) and within-row (WR) management in glufosinate-resistant cotton and 2) the role of soil inversion, cover crops and spring tillage methods for Amaranthus palmeri BR and WR management in glufosinate-resistant cotton. In the first experiment, at 2 weeks after planting (WAP) cotton, Amaranthus palmeri densities, both BR and WR, were reduced =90% following all cover crop treatments in the IT. In the NIT, crimson clover reduced Amaranthus palmeri densities >65% and 50% compared to winter fallow and cereal rye covers, respectively. Averaged across three years, Amaranthus palmeri was controlled =94% in PRE and PRE + POST herbicide regimes regardless of cover crop. Herbicide regime effect on cotton yield was highly significant; the maximum cotton yield was produced by the PRE + POST herbicide regime. In the second experiment, averaged over years and soil inversion, the crimson clover produced maximum cover biomass (4390 kg ha-1) fb cereal rye (3698 kg ha-1) and winter fallow (777 kg ha-1). Two weeks after planting (WAP) and before the postemergence (POST) application, Amaranthus palmeri WR and BR density were two- and four-times less, respectively, in IT than NIT. Further, Amaranthus palmeri WR and BR density were reduced two-fold following crimson clover and cereal rye than following winter fallow at 2 WAP. Without IT, early season Amaranthus palmeri densities were 40% less following DCU, DCH and DD, when compared with IT. Following IT, no spring tillage method improved Amaranthus palmeri control. The timely application of glufosinate + S-metolachlor POST tank mixture greatly improved Amaranthus palmeri control in both IT and NIT systems. The highest cotton yields were obtained with DD following cereal rye (2251 kg ha-1), DD following crimson clover (2213 kg ha-1) and DD following winter fallow (2153 kg ha-1). On average, IT cotton yields (2133 kg ha-1) were 21% higher than NIT (1766 kg ha-1). Therefore, from an integrated weed management standpoint, an occasional fall IT could greatly reduce Amaranthus palmeri emergence on farms highly infested with glyphosate-resistant Palmer amaranth. In addition, a cereal rye or crimson clover cover crop can effectively reduce early season Amaranthus palmeri emergence in both IT and NIT systems. For effective and season-long control of Amaranthus palmeri, one or more POST applications of glufosinate + residual herbicide as tank mixture may be needed in a glufosinate-based cotton production system.