Spatial variation in soil C, N, and trace elements in paddy soil across the coastal, inland, and upland regions of central Vietnam
摘要
This study investigated the distribution of C, N, and selected trace elements (B, Cu, Mo, Zn, As, Cr, Cd, and Pb) in surface soils (0–20 cm) from two functional zones (paddy soils and bund soils) across three topographic regions (coastal, inland, and upland) in 38 long-term (over 50 years continuous crop season) rice-growing communes of central Vietnam. Multivariate analysis of variance (ANOVA) revealed that differences in the elemental concentrations were more strongly influenced by the soil type than by the regional variation (P < 0.05), while the one-way ANOVA showed that no consistent differences in the elemental content were observed among the three regions, except for the upland soils exhibiting significantly higher concentrations of Cr, Cu, and Zn (P < 0.05). Bund soils had significantly higher levels of C, N, and B than paddy soils (P < 0.05), whereas other elemental concentrations were similar between the two zones. The bioconcentration factors of Cd (4.10–15.75) and Zn (1.91–5.16) were substantially higher than those of the other elements, indicating greater mobility and plant uptake potential. Principal component analysis revealed that potential toxic elements exhibited stronger correlations with one another and with soil organic matter than with mineral nutrients, indicating similar geochemical behavior and potential co-accumulation pathways. These findings offer new insights into the spatial variability and ecological interactions of trace elements in rice agroecosystems, highlighting the requirement for site-specific soil management and contaminant risk assessment in central Vietnam.