9781 Review of 2008 by Region - Southeast

Tuesday, January 6, 2009: 10:41 AM
Lila Cockrell Theatre (Henry B. Gonzalez Convention Center)
C. Dale Monks, Auburn University, Auburn, AL

Residual Effect of Primary Tillage on Weed Control and Cotton Yield
C. D. Monks1, M. G. Patterson2, and A. Price3
1,2Ala.
Coop. Ext. System, Auburn University, and 3USDA-ARS

Abstract

A field trial was initiated (2006) to evaluate the effect of at-plant soil preparation, PRE, and POST programs on weed control and cotton yield; and to determine residual effect in subsequent years.  Cotton was planted in a completely randomized experimental design with a 4 X 3 X 2 factorial arrangement of treatments, with at-plant PREP (main plots), PRE herbicide systems (sub-plots), and POST herbicide treatments (sub-sub plots).  At-plant PREP treatments included:  inversion fb disking with pendimethalin PPI; two diskings with pendimethalin PPI; no-tillage with pendimethalin PRE, and no-tillage alone.  PRE treatments included: fluometuron PRE, prometryn PRE, and no PRE. POST treatments included:  glyphosate POST and no POST.   Following initiation in 2006, the trial was planted no-till in 2007 and 2008 using pendimethalin PRE.  After three years, glyphosate-susceptible redroot pigweed populations were significantly reduced when glyphosate was applied POST regardless of the PRE program.  Susceptible pigweed populations were lowest for the no-till/pendimethalin PRE/glyphosate POST program and yield was comparable to the inversion, disk/pendimethalin PPI/glyphosate program.  When no POST glyphosate treatment was applied, population was highest and yield lowest in the no-till plots.  Given the reproductive potential of pigweed, surviving glyphosate-resistant plants in producer's fields would likely continue to infest affected fields.  Further research is required to determine the utility of tillage for herbicide resistance management.