Effects of Functional Vermicompost Application on Cd Migration Control and Environmental Impacts in a Soil-Celery System: A Field Study

Cadmium (Cd) contamination in agricultural soils poses a significant threat to soil quality and food safety. In-situ stabilization is an effective technology to remediate Cd contamination in soil. This study investigated the application of two functional vermicompost (VS and VB separately derived by vermicomposting cow dung added with struvite and biochar) as amendments in soils planted with celery (Apium graveolens L.). The objective was to evaluate their effects on celery growth, Cd migration, as well as the changes in physicochemical and biological properties in soil. The results indicated that, compared to no amendment (CK) and pure vermicompost (VK), the application of VS and VB enhanced celery growth including plant height, fresh weight, and chlorophyll content, etc. Additionally, functional vermicompost effectively retarded Cd migration from soil to celery by reducing its bioavailability coefficient and biological transport coefficient. Besides, the application of VS notably increased soil parameters as available nitrogen (AN), available phosphorus (AP), and the activities of β-glucosidase (β-GC) and sucrase (SU), while VB significantly improved cation exchange capacity (CEC), organic matter (OM), available potassium (AK) content and the activities of urease (UA) and catalase (CAT) in soil. Furthermore, the application of functional vermicompost enhanced bacterial diversity and richness in soil, while also increasing the relative abundance of metal-resistant bacterial taxa including Firmicutes, Proteobacteria and Myxococcota, etc. These findings indicate that both VS and VB have significant potential as effective remediation materials for Cd-contaminated soils, thereby supporting the development of sustainable agricultural practices and environmental restoration efforts.