Cotton seed meal and chicken manure + molasses-induced anaerobic soil disinfestation improved weed and root-knot nematode management in sweetpotato

Authors: SINGH, SIMARDEEP - Clemson University; RUTTER, WILLIAM - Kansas State University; Wadl, Phillip; CAMPBELL, H - Clemson University; BRIDGES, WILLIAM - Clemson University; KARTHIKEYAN, RAGHUPATHY - Clemson University; WARD, BRIAN - Clemson University; ALBORNOZ, KARIN - Clemson University; KHANAL, CHURAMANI - Clemson University; CUTULLE, MATTHEW - Clemson University

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2026
Publication Date: 6/30/2026
Citation: Singh, S., Rutter, W., Wadl, P.A., Campbell, H.T., Bridges, W., Karthikeyan, R., Ward, B., Albornoz, K., Khanal, C., Cutulle, M. 2026. Cotton seed meal and chicken manure + molasses-induced anaerobic soil disinfestation improved weed and root-knot nematode management in sweetpotato. Weed Technology. https://doi.org/10.1017/wet.2026.10106.
DOI: https://doi.org/10.1017/wet.2026.10106

Interpretive Summary: Anaerobic soil disinfestation (ASD) is a promising non-chemical pest management strategy for organic sweetpotato production, particularly against yellow nutsedge and southern root-knot nematode (SRKN). Field studies were conducted in South Carolina to evaluate the impact of ASD using different carbon amendments on these pests. The treatments included Brassica waste (BW), cotton seed meal (CSM), chicken manure with molasses (CM+M), and an unamended control (UC), with different sweetpotato clones. Results showed that CSM and CM+M treatments resulted in greater anaerobicity and reduced yellow nutsedge counts compared to the unamended control. The soil population densities of SRKN were also significantly reduced in the CSM and CM+M treatments, leading to increased marketable sweetpotato yield. Overall, the study demonstrated that CSM and CM+M-induced ASD can effectively manage yellow nutsedge and SRKN while boosting sweetpotato yield in organic production systems.

Technical Abstract: Yellow nutsedge and southern root-knot nematode (SRKN) management is particularly challenging in organic sweetpotato production. Anaerobic soil disinfestation (ASD) has emerged as a promising non-chemical pest management strategy achieved by incorporating labile carbon amendments into the soil, covering the soil with impermeable plastic mulch, and irrigating the amended soil to saturation. Field studies were conducted at the Coastal Research and Education Center, Clemson University, Charleston, South Carolina in the 2023 and 2024 growing seasons to evaluate the impact of ASD on yellow nutsedge and SRKN. Treatments were structured as the factorial arrangement of three carbon amendments [Brassica waste (BW), cotton seed meal (CSM), and chicken manure + molasses (CM+M)] and unamended control (UC) by four sweetpotato clones (‘Bayou Belle’, ‘Monaco’, ‘Murasaki-29’, and USDA-18-040) with four replications using a randomized complete block design . ASD was terminated after three weeks of initiation, and sweetpotato slips were planted one week after ASD termination. Greater cumulative anaerobicity was observed in the CSM and CM+M treatments three weeks after ASD initiation. Six weeks after planting, yellow nutsedge counts across all sweetpotato clones per m2 were 6 to 8 in CSM and 4 to 9 in CM+M treatments compared to 21 to 27 in UC. Both bunch (‘Monaco’ and USDA-18-040) and spreading (‘Bayou Belle’ and ‘Murasaki-29’) type sweetpotato clones resulted in similar yellow nutsedge counts. Soil population densities of SRKN at 16 weeks after planting were reduced by 29 to 46% in CSM treatments and 22 to 44% in CM+M treatments, relative to the UC. The CSM and CM+M treatments increased marketable sweetpotato yield from 31 to 57% compared to the UC. The findings of this study demonstrated that CSM and CM+M-induced ASD have the potential to manage yellow nutsedge and SRKN in organic sweetpotato production systems while increasing the marketable sweetpotato yield.