Characterization of rice grown under traditional and alternative irrigation strategies: As, Cd, and Zn dynamics across multiple varieties, growing seasons, and pore water chemical conditions

Authors: ABU-ALI, LENA - Cornell University; YOON, HYUN - Cornell University; MAGUFFIN, SCOTT - Southern Oregon University; Rohila, Jai; McClung, Anna; REID, MATTHEW - Cornell University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2021
Publication Date: 11/9/2021
Citation: Abu-Ali, L., Yoon, H., Maguffin, S., Rohila, J.S., McClung, A.M., Reid, M.C. 2021. Characterization of rice grown under traditional and alternative irrigation strategies: As, Cd, and Zn dynamics across multiple varieties, growing seasons, and pore water chemical conditions. ASA-CSSA-SSSA Annual Meeting Abstracts. Salt Lake City, Utah. November 7-10, 2021.

Interpretive Summary:

Technical Abstract: Rice paddies are a key environment for studying arsenic (As) fate and transport. Because it is a staple food for half of the world, rice cultivation receives much attention for being a major source of dietary exposure to As. Rice has also been identified as the primary source of cadmium (Cd) intake in the general Japanese population. The Alternate Wetting and Drying (AWD) irrigation practice prevents plant accumulation of As by altering the biogeochemistry of the rice paddy. The introduction of oxygen into the soil column causes reduced, mobile As(III) to be oxidize to As(V) and absorb to the re-oxidized Fe minerals, rendering the As unavailable for plant uptake. However, AWD also favors the mobility and bioavailability of Cd, a carcinogen, and zinc (Zn), an important nutrient. The objective of this project was to quantify rice-grain metal concentrations and As speciation in multiple varieties of rice grown under continuously flooded or AWD irrigation strategies. One, two, and three drains were tested to evaluate the efficacy of drain frequency using AWD. Field plots were prepared at the Dale Bumpers National Rice Research Center in 2017 and 2018. In 2018, rice paddy soil physical chemical properties were monitored with in-situ sensors and porewater samplers. Brown rice samples were extracted for total grain As, Cd, Mn, Fe, Zn, and As speciation and relationships between irrigation treatment, rice variety, and trace metal concentration and speciation in rice grains, and rice yields were explored. A rich dataset of pore water chemistry will be used as a resource for data interpretation. We hypothesize that AWD decreases grain As content while increasing grain Cd and Zn content, with pore water chemistry predicting rice grain chemistry. Additionally, we hypothesize that rice cultivars bred to be drought-resistant will be less susceptible to any yield reductions caused by AWD.