Arsenic (As) poses a double threat to global food security by lowering rice yields and directly impacting human health via consumption of As-contaminated grains.  Since the dominant chemical form of As in flooded paddy soil, arsenite, and dissolved silicon (Si) share a root-uptake pathway, a promising strategy to abate As uptake by rice and improve rice yields is to increase the plant-available Si in paddy soil.  However, Si and As also compete for sorption sites onto soil solids, and alteration of dissolved Si may thus affect As mobility.  Alteration of Si can also affect the mineralogy of newly formed iron (Fe) oxide plaque, which can sequester As.  Here, we incorporate different forms of Si into paddy soil and investigate the fate of As and impacts on Fe plaque using spectroscopic and conventional tools.  We show that Si alteration can affect the quantity and mineralogy of Fe oxide plaque, associated As, and can improve rice yields depending on the choice of amendment.  These processes occurring at the soil-plant interface will be discussed in the larger context of global food security.<br/>

Fate of arsenic at the soil-plant interface: Impacts of soil-incorporation of plant-available silicon on arsenic desorption, iron oxide plaque, and plant uptake

249th National Meeting (2015)

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