To clarify how straw pretreatment regulates fomesafen (FOM) residue-induced maize phytotoxicity, material characterization, batch adsorption experiments and pot trials were conducted in a soil-maize system. Crushed straw (CS), decomposed straw (DS) and carbonized straw (BS) were compared in terms of FOM partitioning, soil nutrient status and FOM accumulation in maize. Under equivalent raw-straw input, DS and BS enhanced FOM partitioning into the soil solid phase. Equal external organic carbon validation showed that BS and DS had similar FOM partitioning capacities in soil-straw mixtures, both higher than CS, indicating that treatment differences were not determined solely by external organic carbon input. In the pot trial, straw incorporation reduced shoot FOM concentrations by 43.77%-66.04% and promoted FOM retention in roots. BS increased shoot biomass under FOM stress by 56.30%, whereas DS improved soil carbon and nitrogen status and increased root biomass by 34.10%. Dual-function analysis indicated that BS was more effective in alleviating shoot phytotoxicity, whereas DS showed a more balanced response between pollution control and nutrient compensation. These results provide a basis for selecting straw pretreatment and returning strategies for FOM-contaminated fields in the Mollisols region of Northeast China.