Effectiveness of anaerobic soil disinfestation for weed and nematode management in organic sweetpotato

Authors: SINGH, SIMARDEEP - Clemson University; Rutter, William; Wadl, Phillip; CAMPBELL, HARRISON - Clemson University; KHANAL, CHURAMANI - Clemson University; CUTULLE, MATTHEW - Clemson University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2024
Publication Date: 8/28/2024
Citation: Singh, S., Rutter, W.B., Wadl, P.A., Campbell, H.T., Khanal, C., Cutulle, M.A. 2024. Effectiveness of anaerobic soil disinfestation for weed and nematode management in organic sweetpotato. Agronomy 2024. 14(9):1935. https://doi.org/10.3390/agronomy14091935.
DOI: https://doi.org/10.3390/agronomy14091935

Interpretive Summary: Among organic vegetable crops in the United States, sweetpotato ranks fifth in terms of commodity sales. Despite the added value, organic sweetpotato production is anticipated to yield lower than conventional systems due to management challenges of weeds and nematodes. Due to the aggressive nature of weeds and the lack of effective methods for the management of root-knot nematodes that invade organic sweetpotato fields, there is an urgent need to develop alternative non-chemical based management strategies. Anaerobic soil disinfestation (ASD) is a promising non-chemical based alternative to soil fumigation for organic production systems. Therefore, Clemson University and USDA researchers investigated the success of ASD to control weeds and root-knot nematode in sweetpotato for three soil types (clay, sandy loam, and Wagram sand) in South Carolina. Results suggested that the plots that went anaerobic generally had fewer weeds and nematodes when compared to plots that did not go anaerobic. The addition of cotton seed meal as a carbon source for ASD resulted in similar foliar biomass of sweetpotato compared to no carbon amendment treatments. Overall, this study will improve our understanding of using ASD to manage root-knot nematodes and weed infestation in sweetpotato.

Technical Abstract: Weeds and nematodes are particularly problematic in organic sweetpotato production due to the lack of effective pesticides. Anaerobic soil disinfestation (ASD) has the potential to fit into current pest management practices as an alternative to pesticides. Greenhouse studies were conducted at the Clemson Coastal Research and Education Center in Charleston, SC, to specifically investigate the impact of carbon source and soil type on cumulative anaerobicity, weed control, nematode population level, and sweetpotato vigor. Microcosms were filled with one of three different soil types (Charleston-loamy/native, Blackville-coarse high sand content, and Clemson-high clay content) and were mixed with cottonseed meal or no carbon amendment. Tiff film was then sealed over the pots for 6 weeks followed by transplanting of sweetpotato (cv Bayou Belle) slips. Results suggested that the plots receiving the carbon amendment spent the most time under anaerobic conditions. Experimental units that went anaerobic generally had fewer weeds (49%) and nematodes (13/100 cm3 soil) when compared to plots that did not go anaerobic. The addition of cotton seed meal as a carbon source resulted in similar above-ground biomass of sweetpotato compared to no carbon amendment treatments. Overall, this study will improve our understanding of using ASD to manage root-knot nematodes and weed infestation in sweetpotato.