319-3 The Effect of Si Amendments on As Accumulation and Greenhouse Gas Emissions in Rice (Oryza sativa L).

Poster Number 1327

See more from this Division: SSSA Division: Soil Chemistry
See more from this Session: Soil Biogeochemistry of Redox Driven Processes and Effects on Chemical Cycling of Nutrients and Contaminants: II

Tuesday, November 17, 2015
Minneapolis Convention Center, Exhibit Hall BC

William Teasley1, Angelia L. Seyfferth2, Andrew H Morris3 and Alaina Johansson1, (1)University of Delaware, Newark, DE
(2)152 Townsend Hall, University of Delaware, Newark, DE
(3)Ecosystem Science and Management, Pennsylvania State University, University Park, PA
Poster Presentation
  • SSSA Conference Poster Teasley-als.pdf (830.0 kB)
  • Abstract:
    The contamination of rice with arsenic is a human health problem of global significance.
    South and Southeast Asia have been afflicted by high levels of naturally derived arsenic
    in groundwater. Due to the tradition of paddy (flooded) cultivation, rice plants can
    potentially accumulate arsenic. Irrigating rice with contaminated water has led to
    elevated levels of arsenic. However, silicon, which has been shown to increase yield and
    disease resistance in rice crops, may decrease arsenic accumulation in rice. Silicon
    shares an uptake pathway with the predominant form of arsenic in paddy soils, and thus
    enriching the soil solution with dissolved silicon will result in competition between
    silicon and arsenic for rice uptake. While in practice, silicon enrichment could be
    accomplished by returning rice residues (straw and husk) back to the paddy, labile carbon
    additions (i.e. straw) to paddy fields have been implicated with increased emissions of
    methane, a potent greenhouse gas. Recognizing the need for solutions that simultaneously
    decrease arsenic uptake and GHG emissions without decreasing rice yields, we evaluated the
    effect of silicon amendments on arsenic uptake and greenhouse gas emissions in rice in a
    pot experiment. Pots were amended with 3 different high Si, low C materials (rice husk,
    husk ash, and calcium silicate). Over the course of rice growth, porewater As, Fe2+, and
    Si, pH and redox were monitored. In addition, weekly measurements of GHG fluxes were
    made. The plants were harvested at maturation and tissue samples were analyzed for
    arsenic content. We hypothesized that increasing porewater Si will decrease arsenic
    uptake in rice plants due to competition between arsenic and silicon for plant uptake. In
    addition, increased silicon in porewater may decrease methane emissions (relative to
    controls) through increased rhizosphere oxidation. These findings will be discussed in
    the context of global food security.

    See more from this Division: SSSA Division: Soil Chemistry
    See more from this Session: Soil Biogeochemistry of Redox Driven Processes and Effects on Chemical Cycling of Nutrients and Contaminants: II