Permanent living mulches of white clover and bird's‐foot trefoil affect the biomass and nutraceutical quality of organic broccoli ( Brassica oleracea L. var. italica ) inflorescences

BACKGROUND: The present 2-year field trial aims to assess the effects of permanent living mulches (pLMs) of Trifolium repens (TRFRE) and Lotus corniculatus (LOTCO) on agronomic performance, and phytochemical and nutraceutical profile of broccoli (Brassica oleracea var. italica) in an organic-conservative Mediterranean vegetable system. Standard organic management, including tillage and fertilization, was used as the reference cropping system (CNT). Parameters assessed included biomass accumulation, glucosinolates (GSLs), phenols, chlorophylls, ascorbic acid, and antioxidant activity in broccoli inflorescence. RESULTS: Although broccoli cultivated with pLMs showed reduced marketable biomass in 2022, both treatments maintained stable yields across 2 years despite differing environmental conditions. In contrast, CNT, which yielded well in 2022, had a marked biomass reduction in 2024, due to soil compaction from intense post-transplant rainfall. LOTCO consistently enhanced total phenol accumulation and antioxidant capacity across seasons, while chlorophyll and ascorbic acid content fluctuated in line with biomass performance. GSL concentrations in broccoli showed marked seasonal variability, with overall higher levels in 2022 compared to 2024. This difference was particularly pronounced for glucoraphanin and 4-methoxyglucobrassicin (4OM-GBS). In both seasons, the effects of pLMs, which reflected broccoli biomass production, modulated the concentration of specific GSLs. A positive correlation was observed between broccoli biomass and GSL concentration, especially for 4OM-GBS, glucobrassicin, and neoglucobrassicin. CONCLUSION: pLMs can support broccoli production in organic and conservative cropping systems by enhancing phytochemical profiles and improving resilience to abiotic stresses. While biomass reductions may occur compared to conventional organic systems, pLMs show potential to stabilize both yield and nutraceutical quality. © 2026 Society of Chemical Industry.