Winter Cover Crops and Vinegar for Early-Season Weed Control in Sustainable Cotton

Abstract

ABSTRACT. Weeds may be suppressed by winter cover crops and the use of organic herbicides such as vinegar. Black oat (Avena strigosa) and hairy vetch (Vicia villosa) winter cover crops were planted for 2 years as part of a sustainable production system for cotton in the Lower Rio Grande Valley of Texas, and were till-killed each spring prior to cotton planting. Palmer amaranth (Amaranthus palmeri), common purslane (Portulaca oleracea), and sunflower (Helianthus annuus) were frequently-encountered winter and spring weeds. Both cover crops controlled winter weeds as well as did winter tillage without cover. Black oats plots had 8% and 17% more total winter weed cover than no-cover and hairy vetch plots, respectively. Seven weeks after cotton planting, cotton cover was 10% to 15% less in former winter hairy vetch and no-cover sustainable plots than in former black oats plots, but cotton height did not vary by winter cover crop. Total spring weed, pigweed, and purslane cover did not vary between former hairy vetch, black oats, and no-cover plots. All sustainable plots had higher spring weed cover than did conventional plots maintained with cultivation and synthetic herbicides. Breakdowns in the sustainable spring weed management system (withholding of spring cultivation) or insect pest P. J. Moran and S. M. Greenberg are affiliated with the USDA-Agricultural Research Service, Beneficial Insects Research Unit, 2413 E. Hwy 83, Weslaco, TX 78596 (E-mail: Patrick.Moran@ars.usda.gov; Shoil.Greenberg@ars.usda.gov).Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.Address correspondence to: P. J. Moran at the above address.This article is a U.S. government work, and is not subject to copyright in the United States. JOURNAL OF SUSTAINABLE AGRICULTUREmanagement system (failure of alfalfa strips) led to increases of 60% or more in weed cover in sustainable plots. Cotton lint yield (kg/ha) did not differ between sustainable and conventional weed management systems. When evaluated as a cover crop and weed management tool, vinegar containing 9% acid (1,550 L/ha) reduced live hairy vetch cover to less than 5% in one of two trials, but was not effective as a burndown herbicide on black oats. Vinegar at this concentration (2,980 L/ha) killed >80% of 30-day-old or younger cotton and sunflower and 10-day-old Palmer amaranth and purslane in field trials, but caused <50% mortality to mature Palmer amaranth and purslane. More dilute vinegar solutions (0.9% to 4.5% acid) caused little or no mortality. Black oats and hairy vetch covers controlled winter but not spring weeds in this production system. With more prolonged use, winter covers could become a key spring weed control component in sustainable cotton production. Vinegar could be useful in controlling young weed seedlings in non-crop areas, or as a follow-up to cultivation.

Effects of cultural system (organic and conventional) on growth and fiber quality of two cotton (Gossypium hirsutumL.) varieties

“…Turkey, India, China, Syria, Uganda, Tanzania, Israel, USA and Pakistan are the top ten organic cotton producing countries in the world, according to Organic Exchange. However, there are few references to organic cotton in the literature 2 , 9 , 10 . A niche market for organic cotton appears to already exist and is constantly growing.…”

Global Meta‐Analysis of Cotton Yield and Weed Suppression from Cover Crops

“…The size of the cover crop effect on lint yield varied more among cultivars than it did for seed cotton yield, from −6% for Fibermax to 33% for the "other" category (Fig. Cultivars representing the 49% decrease in weed biomass were Fibermax, Campo, and Sicot (Duggan et al, 2005;Moran and Greenberg, 2008;Vasilakoglou et al, 2011). None of the individual cultivars had lint yields that were affected by cover cropping.…”

“…Cover cropping reduced weed biomass by an average of 16% in cultivar Stoneville and 22% in Deltapine. Cultivars representing the 49% decrease in weed biomass were Fibermax, Campo, and Sicot (Duggan et al, 2005;Moran and Greenberg, 2008;Vasilakoglou et al, 2011).…”

Principles and Practices of Integrated Pest Management on Cotton in the Lower Rio Grande Valley of Texas

“…Two years of winter cover cropping did not obviate the need for cultivation, and hand-weeding for sustainable spring weed management in cotton in the LRGV of Texas. (Moran & Greenberg, 2008).…”