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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #418004
Research Project: Broadening and Strengthening the Genetic Base of Rice for Adaptation to a Changing Climate, Crop Production Systems, and Markets

Location: Dale Bumpers National Rice Research Center

Title: Effect of alternate wetting and drying and organic matter addition on greenhouse gas and arsenic dynamics in rice paddy soil

Author
item VEGA, MICHAEL - Cornell University
item DIGNAM, WILLIAM - Cornell University
item SLADE, AVA - Cornell University
item WEIDMAN, GIANNA - Cornell University
item Rohila, Jai
item REID, MATTHEW - Cornell University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Irrigation management and soil organic carbon (C) content are significant drivers of greenhouse gas emissions and arsenic uptake by rice plants during rice cultivation. Research has shown that alternate wetting and drying (AWD) can reduce methane emissions and increase water use efficiency, though often at the expense of denitrification-derived nitrous oxide release during re-wetting events of AWD. Experiments hypothesize that high carbon to nitrogen (C/N) ratios in soil could favor dissimilatory nitrate reduction to ammonia (DNRA) over denitrification, decreasing nitrous oxide production and retaining aqueous nitrogen as ammonium rather than exporting nitrogen as nitrous oxide gas emissions. To test this hypothesis, we conducted greenhouse scale experiments integrating AWD with the addition of dry leaves to the soil matrix as a source of organic carbon. An overarching goal of these experiments was combining AWD with increased C/N ratios to select for DNRA and reduce nitrous oxide emissions from rice paddies during re-wetting events. The increased C/N ratios stimulated DNRA reducing nitrous oxide flux, and by arsenite oxidation, helped in reducing arsenic bioavailability in the soil porewater for rice uptake. Overall, this contribution will present on soil water content, porewater (e.g., dissolved nitrogen and arsenic speciation), and greenhouse gas flux data as it interfaces with wetting/drying events and variable C/N ratios, with a goal of reducing methane and nitrous oxide emissions simultaneously, while also reducing the availability of arsenic in porewater for uptake by rice plants.