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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #304764
Title: Reducing greenhouse gas emissions, water use and grain arsenic levels in rice systems

Author
item LINQUIST, BRUCE - University Of California
item ANDERS, MERLE - University Of Arkansas
item ADVIENTO-BORBE, MARIA - University Of California
item Chaney, Rufus
item NALLY, LAWTON - University Of Arkansas
item DA ROSA, ELIETE - Federal Institute Of Technology
item VAN KESSEK, CHRIS - University Of California

Submitted to: Global Change Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2014
Publication Date: 1/15/2015
Citation: Linquist, B., Anders, M.A., Adviento-Borbe, M., Chaney, R.L., Nally, L., Da Rosa, E., Van Kessek, C. 2015. Reducing greenhouse gas emissions, water use and grain arsenic levels in rice systems. Global Change Biology. 21(1);407-417. doi: 10.1111/GCB.12701.

Interpretive Summary: Production of rice using continuous flood irrigation has been found to cause increased greenhouse gas emissions (methane and nitrous oxide), compared to more aerobic water managment. In addition, flood management increases grain arsenic concentrations compared to three methods of “alternate wetting and drying (AWD)” irrigation management. To evaluate the effect of water management on both productivity, greenhouse gas production and arsenic in grain, rice was grown in Arkansas in several years, within two crop rotations with regular measurement of gas emissions, and recording of water use and rainfall to characterize efficiency of water use in rice production. AWD management strongly reduced methane and nitrous oxide emissions and increased carbon dioxide emissions somewhat. Overall, summed greenhouse gas emissions were strongly reduced by AWD. Yield was affected only in the driest of four AWD practices, with highest emissions CO2-equivalent from rice-rice rotation compared with rice-soybean rotation. Water use efficiency was significantly improved using AWD compared to continuous flood. Grain arsenic was strongly reduced by AWD management, which avoided flood after the initial flood treatment post germination. Overall, the findings of this study indicate that important environmental and food safety benefits can be obtained without sacrificing yield. Breeding cultivars adapted to this AWD management might provide further improved yields and reduced grain arsenic under AWD management.

Technical Abstract: Agriculture is faced with the challenge of providing healthy food for a growing population while minimizing environmental consequences. Rice (Oryza sativa), the staple crop for the largest number of people on earth, is grown under flooded soil conditions and uses more water and has higher greenhouse gas (GHG) emissions than most crops. The objective of this study was to test the hypothesis that alternate wetting and drying (AWD - flooding the soil and then allowing to dry down before being reflooded) water management practices will maintain grain yields and concurrently water use, greenhouse gas emissions and arsenic (As) levels in rice will be reduced. Various treatments ranging in frequency and duration of AWD practices were evaluated at three locations over two years. Relative to the flooded control treatment and depending on the AWD treatment, yields were reduced by < 1 to 13%; water use efficiency was improved by 18 to 63%, global warming potential (GWP of CH4 and N2O emissions) reduced by 45 to 90%, and grain As concentrations reduced by up to 63%. In general, as the severity of AWD increased by allowing the soil to dry out more between flood events, yields declined while the other benefits increased. The reduction in GWP was mostly attributed to a reduction in CH4 emissions as changes in N2O emissions were minimal among treatments. When AWD was practiced early in the growing season followed by flooding for the remainder of the season, similar yields as the flooded control were obtained but reduced water use (18%), GWP (45%) and yield-scaled GWP (45%). This highlights that environmental benefits can be realized without sacrificing yield both in terms of climate change mitigation and adaptation (e.g., to reduced water). However, adoption of these practices will require that they are economically attractive and can be adapted to field scales.