Weed management by summer cover crops, solarization and anaerobic soil disinfestation in plasticulture

Authors: GURSEWAK, SINGH - Clemson University; WARD, BRIAN - Clemson University; Levi, Amnon; CUTULLE, MATTHEW - Clemson University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2022
Publication Date: 11/5/2022
Citation: Gursewak, S., Ward, B., Levi, A., Cutulle, M. 2022. Weed management by summer cover crops, solarization and anaerobic soil disinfestation in plasticulture. HortScience. 12(11):2754. https://doi.org/10.3390/agronomy12112754.
DOI: https://doi.org/10.3390/agronomy12112754

Interpretive Summary: Organic Agriculture is the fastest growing sector of the United States (U.S.) food industry. More than 100,000hectares are transitioning to organic production, and organic vegetable production has increased by 27% since 2017. However, weed control is the major hindrance and is one of the most challenging, costly, and time-consuming aspects of crop production for most organic crop growers. Increasing global demand for organic food, especially vegetables, necessitates the development of non-chemical methods useful for weed control in organic vegetable crops. Anaerobic soil disinfestation (ASD) is a novel non-chemical approach, generating anaerobic conditions in the topsoil layer. The concept of ASD is based adding an organic source to the topsoil which is covered with polyethylene (a large plastic sheet) for several weeks to produce anaerobic conditions resulting from intense microorganisms’ activity in the moist soil. In this study, ARS scientists collaborated with a Clemson University team on evaluating the effect of ASD versus non-ASD treatment on tometo production in Charleston, South Carolina. Tomato plants transplanted into plots that were undergone ASD treatment were more vigorous and produced higher yields compared with these in plots that did not undergo ASD. This study demonstrates that ASD could reduce weed infestation and promote organic tomato production in South Carolina. The results of this study should be useful for organic vegetable growers, extension people, and researcher interested in reducing weed infestation in organic vegetable fields.

Technical Abstract: Weeds negatively affect organic vegetable crop growing and profitability. Weed control management is the greatest challenge for vegetable organic growers since control options are limited for organic vegetable production. Anaerobic soil disinfestation (ASD) is a novel non-chemical approach, generating anaerobic conditions in the topsoil layer for a limited period. The concept of ASD is based mainly on the addition of organic sources (usually an evaporating carbon source) to the topsoil to promote anaerobic conditions driven by microorganisms in moist soil mulched with polyethylene. Cover crops can be utilized as ASD labile carbon sources. Field studies were conducted in the fall of 2020 and 2021 to determine the efficacy of warm season cover crops used as carbon sources for ASD and their role in weed management. The study included four cover crop treatments in a factorial experimental design, including Sorghum-Sudangrass, Sunn Hemp, both or none, by two polyfilm treatments (aerated or not aerated). Cover crops were grown for 75 days and incorporated into the soil and sealed with totally impermeable film (TIF) clear mulch and ASD was performed for four weeks. All incorporated cover crop treatments generated moderate to higher anaerobic conditions (0 - 150 mV) and provided adequate weed control (P < 0.05). Tomato plants transplanted in non-aerated cover crop plots were more vigorous and produced higher yields compared with these in non-treated plots. No phytotoxicity was observed on tomato plants following ASD treatment. This study demonstrated that warm season cover crops could potentially serve as a carbon source for ASD in organic tomato production.