Rice grown in the South-Central USA tends to accumulate a larger fraction of methylarsenic species than rice grown in other regions, and the reason for these patterns are not clear. The goal of this study was to determine how soil management conditions influence the persistence and plant uptake of methylarsenic species in rice paddy soils, using field-scale experimental plots in Arkansas, USA. We expect methylated arsenic to persist in pore water and be more abundant in biomass in continuously flooded grown rice.