ABSTRACT
Rice plants have a high ability to acquire arsenic (As), from flooded paddy soils and accumulate As in rice grains, posing harmful consequences on human health. In the present study, iron-modified biochar (Fe-BC) was used with foliar silica sol (Si) in an As-contaminated paddy soil in order to reduce As accumulation in rice grains for safe production. The results showed that the amendments of Fe-BC and Si significantly increased grain yields (P < 0.05), and decreased As concentration in brown rice (P < 0.05) after application for 2 years. The amendment of Fe-BC + Si resulted in the largest reductions in As accumulation in brown rice with an average reduction of 39-48% for four growing seasons, which led to the As concentration in brown rice below 0.20 mg/kg after 2-year practice. The pH value in the soil solution increased from 4.6 to 5.1, which was significantly negative correlated with soil available As. In conclusion, co-application of iron-modified biochar and foliar silica sol could be used as an effective strategy to reduce the As contents in rice grains.
