Application of Triple Superphosphate to Alleviate Arsenic Toxicity in Rice

Rice is highly susceptible to arsenic accumulation comparing to other cereal crops. Accumulation of arsenic in plant at high level can severely inhibit plant growth. According to previous study which reported that phosphate fertilizer application can decrease As toxicity due to the similarity of chemical properties between arsenate and phosphate. Both ions are taken up by plants by the same uptake system but phosphate is more competitive compare to arsenate. Therefore, the study was aimed to investigate the effect of phosphate fertilizer on growth, arsenic and nutrient uptake of rice. The different levels of phosphate were added to soil with different levels of arsenic. The soil with high arsenic concentration (10 mg As kg-1) and not too high (no As added) but higher concentration than As citrical level showed arsenic toxicity symptom in rice during panicle initiative stage. Application of phosphate fertilizer in soil with too high arsenic concentration did not alleviate arsenic toxicity in rice, resulting in decreased plant growth and nutrient uptake.  However, in soil with not too high arsenic concentration, plant growth and nutrient uptake tended to increase and arsenic in grain decreased. Therefore, application of phosphate fertilizer to alleviate arsenic toxicity is a suitable strategy in soils that are not too high in arsenic concentration.