Influence of cropping rotation and straw management on Cd accumulation in rice ( Oryza sativa L.): a perspective from the rape ( Brassica campestris )–rice system

Cadmium (Cd) contamination is a major concern due to its toxicity and bioaccumulation in crops. The study researched the impact of rape (Brassica campestris) cultivation and influence of straw management on Cd accumulation in rice (Oryza sativa L.) under rape-rice rotation system. Field experiments were set in moderately Cd-contaminated farmlands, with treatments including rape-rice rotation with straw removal (NR), rape-rice rotation with straw return (RR), and single cropping rice (SR). In contrast with SR, the NR effectively reduced 6.67-19.59% soil available Cd and the 37.18-39.10% rice grains Cd accumulation during 3 years. Compared with the RR, SR significantly decreased 17.17-27.78% soil available Cd concentrations and 33.30-53.84% rice grain Cd accumulation. Soil physical and chemical properties were influenced by rape cultivation and straw return, further affecting Cd mobility. This study underscores that rape-rice rotation with straw removal can be an effective tactic for reducing the Cd contamination in rice grains and improve soil environment. This research provides critical insights into sustainable agricultural practices for Cd-contaminated soils, offering practical solutions for mitigating Cd risk in rice, while highlighting the importance of straw management in crop rotations.