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ARS Home » Southeast Area » Auburn, Alabama » Soil Dynamics Research » Research » Publications at this Location » Publication #361216

Research Project: Conservation Systems to Improve Production Efficiency, Reduce Risk, and Promote Sustainability

Location: Soil Dynamics Research

Title: Influence of cover crop mixture, cover crop placement, and herbicides on weed control in cotton

item JOHNSON, ANNA - Auburn University
item Price, Andrew

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/2019
Publication Date: 2/6/2019
Citation: Johnson, A., Price, A.J. 2019. Influence of cover crop mixture, cover crop placement, and herbicides on weed control in cotton [abstract]. Southern Weed Science Society Annual Meeting. p. 145.

Interpretive Summary:

Technical Abstract: The inclusion of winter cover crops is a common tool for integrated weed management in both conventional and conservation systems. Two trials at E.V. Smith Research Center in Shorter, AL were established in November of 2016 to evaluate the efficacy of several cover crop systems as an additional form of weed control in cotton. One trial evaluated herbicide timing over a rye (Secale cereal) treatment and a mixture of rye, oats (Avena sativa), wheat (Triticum aestivum), crimson clover (Trifolium incarnatum), and tillage radish (Raphanus sativus) in comparison to winter fallow. Each cover crop system was evaluated under four herbicide regimes including non-treated, PRE only (pendimethalin and fomesafen), POST only (dicamba and glyphosate), and PRE+POST treatments. The second trial compared several cover crop mixtures and precision drill placements (under a PRE+POST herbicide system). The treatments included winter fallow, rye through the whole plot and row middles only, a mixture of crimson clover and tillage radish through the whole plot and in-row only, and a mixture of rye, crimson clover, and tillage radish over the whole plot and with precision placements. Cover crop biomass was lower in 2018 in both trials due to delayed planting. In the cover crop mixture and herbicide timing trial, Amaranthus spp. pressure was generally higher in 2018 compared to 2017, with control highest in the PRE+POST treatments and the PRE only rye treatment. Large crabgrass (Digitaria sanguinalis) also differed between treatments with the least control under the nontreated winter fallow system. Cover crops did not influence yield compared to winter fallow. However, yields differed between years and herbicide treatments. In the cover crop placement trial, there were no differences between cover crop treatments in terms of weed control and yield. Yield was higher in 2018, which varied from 4321 to 4805 kg ha–1, while 2017 yield ranged from 3205 to 3600 kg ha–1.