Effect of cover crop biomass, strip-tillage residue width, and pre-herbicide placement on cotton weed control, yield, and economics

Authors: Price, Andrew; NICHOLS, ROBERT - Cotton, Inc; Morton, Trent; Balkcom, Kipling; LI, STEVE - Auburn University; GREY, TIMOTHY - University Of Georgia

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2021
Publication Date: 1/26/2021
Citation: Price, A.J., Nichols, R., Morton, T.A., Balkcom, K.S., Li, S., Grey, T. 2021. Effect of cover crop biomass, strip-tillage residue width, and pre-herbicide placement on cotton weed control, yield, and economics. Weed Technology. 35:385–393. https://doi.org/10.1017/wet.2021.8.
DOI: https://doi.org/10.1017/wet.2021.8

Interpretive Summary: Conservation tillage hecterage continues to be threatened by glyphosate-resistant Palmer amaranth and other troublesome weeds. Integrated control practices, including PRE-herbicides and high cover crop biomass conservation systems, decrease weed emergence. Field experiments were conducted from autumn 2010 through crop harvest in 2013 at two locations in Alabama to evaluate the effect of integrated weed management practices on weed control and seed cotton yield in glyphosate-resistant cotton. A cereal rye cover crop system was evaluated consisting of high or low biomass, each followed with wide or narrow within-row strip-tillage. Additionally, four herbicide regimes were evaluated. In most comparisons, tillage width, residue amount, and soil applied herbicide placement did not influence within-row weed control; however, broadcast PRE resulted in increased weed control in row middles compared to plots receiving banded PRE. Banded PRE herbicides resulted in equivalent yields compared to broadcast PRE in most comparisons, thus saving time and input costs. Conservation tillage cotton would likely benefit from broadcast soil-applied herbicide applications regardless of residue amount and tillage width when infested with Palmer amaranth and other troublesome weed species.

Technical Abstract: Conservation tillage hecterage continues to be threatened by glyphosate-resistant Palmer amaranth and other troublesome weeds. Integrated control practices, including PRE-herbicides and high cover crop biomass conservation systems, decrease weed emergence. Field experiments were conducted from autumn 2010 through crop harvest in 2013 at two locations in Alabama to evaluate the effect of integrated weed management practices on weed control and seed cotton yield in glyphosate-resistant cotton. A cereal rye (Secale cereale L.) cover crop system was evaluated consisting of high or low biomass, each followed with wide or narrow within-row strip-tillage. Additionally, four herbicide regimes consisted of 1) pendimethalin at 0.84 kg ae/ha-1 plus fomesafen at 0.28 kg ai/ha-1 applied PRE broadcast, 2) pendimethalin plus fomesafen applied PRE banded on the row, or 3) no PRE, with each (1-3) followed by (fb) glyphosate (1.12 kg ae ha-1) applied POST fb a LAYBY applications of diuron (1.12 kg ai ha-1) plus MSMA (2.24 kg ai ha-1). Low residue plots ranged in biomass from 85 kg ha-1 to 464 kg ha-1, while high biomass plots ranged from 3119 kg ha-1 to 6929 kg ha-1. In most comparisons, tillage width, residue amount, and soil applied herbicide placement did not influence within-row weed control; however, broadcast PRE resulted in increased weed control in row middles compared to plots receiving banded PRE. Banded PRE herbicides resulted in equivalent yields compared to broadcast PRE in most comparisons, thus saving time and input costs. Conservation tillage cotton would likely benefit from broadcast soil-applied herbicide applications regardless of residue amount and tillage width when infested with Palmer amaranth and other troublesome weed species.