Integrated Use of Soil Solarization (SS) and Anaerobic Soil Disinfestation (ASD) Reduces Weed Emergence in Tomato and Bell Pepper Production in South Carolina

Anaerobic soil disinfestation (ASD) and soil solarization (SS) are promising nonchemical management approaches that leverage biological and physical processes to manage weeds, soilborne pathogens, and modify soil chemical properties in vegetable production. Field trials were conducted to evaluate SS-ASD using molasses (M), mustard seed meal (MSM), and their combination (M+MSM), under clear polyethylene mulch, with or without sealed beds to create SS-ASD or USS (unsealed soil solarization) conditions. SS-ASD treatments provided stronger soil disinfestation than SS alone, characterized by redox potential (Eh) below −140 mV, soil pH 5.3, and mean soil temperatures of 39.6 °C, with temperatures exceeding the critical 40 °C threshold for 120 hours. SS-ASD treatments with carbon sources reduced yellow nutsedge shoot density by >90% and grass weeds by nearly 80% at 90 days after treatment. SS-ASD treatments resulted in improved marketable yield in some cases; however, responses were inconsistent across years, and early-season phytotoxicity was observed in tomato ( Solanum lycopersicum L.) and bell pepper ( Capsicum annuum L.). This study demonstrated that integrating SS-ASD can effectively control weeds; however, additional research is needed to validate crop safety and optimization under production systems.