Effect of organic fertilization practiced in paddy soils in Bangladesh on arsenic dynamics

摘要

A greenhouse rice growth trial was conducted to find the effect of Farm Yard Manure (FYM) and rice straw, at a field application rate practiced in Bangladesh (5 t/ha), on arsenic (As) mobilization in soil. Organic Matter (OM) amendments lead to considerable mobilization of As into both soil porewaters and standing surface waters. Greatly enhanced As mobilization in porewater was observed initially (<24 d), but As mobilization decreased during later rice growth, particularly at grain fill. Total soil As was 12.7 ± 0.2 mg/kg and the highest As mobilization in porewater after 10 d following transplanting was found to be 0.73 ± 0.1 and 0.85 ± 0.2 mg/L with and without OM amendment, respectively. At 108 d, As concentration reduced to 0.05 ± 0.01 and 0.04 ± 0.01 mg/L with and without OM amendment, respectively. OM fertilization greatly enhanced As mobility to surface waters, which may have major implications for fate of As in paddy agronomic ecosystems.