Influence of rice cultivation on the abundance and fractionation of Fe, Mn, Zn, Cu, and Al in acid sulfate paddy soils in the Pearl River Delta

摘要: Abstract Many of the areas dominated by acid sulfate (AS) soils in southern China have been reclaimed for rice cultivation and represent an important source agricultural production food security local population. In this study, we examined abundance partitioning Fe, Mn, Zn, Cu, Al both paddy fields uncultivated using a six-step sequential extraction procedure. Rice significantly reduced acidity levels at soil depths 0–100 cm, but 100–140 cm increased significantly. A substantial loss Mn oxide acidified layer (0–100 cm) compared to underlying parent material was observed, there were few changes concentrations Fe Zn throughout profile. However, Cu substantially enriched superficial (0–40 cm) subsoil (40–140 cm). general, leaching higher because intensified irrigation flood conditions, whereas accumulation mainly form “acid soluble” “crystalline iron oxide” than fields. The most marked declines metal occurred “labile” fractions, as result cultivation, which readily mobilized fractions heavy metals these soils.