Reducing greenhouse gas emissions,water use,and grain arsenic levels in rice systems |
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Authors: | Bruce A. Linquist Merle M. Anders Maria Arlene A. Adviento‐Borbe Rufus L. Chaney L. Lanier Nalley Eliete F.F. da Rosa Chris van Kessel |
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Affiliation: | 1. Department of Plant Sciences, University of California, Davis, CA, USA;2. Department of Crop, Soil and Environmental Sciences, University of Arkansas Rice Research & Extension Center, Stuttgart, AR, USA;3. United States Department of Agriculture, Crop Systems and Global Change Laboratory, Beltsville, MD, USA;4. Department of Agricultural Economics and Agribusiness, University of Arkansas, Fayetteville, AR, USA;5. Federal Institute of Science Education and Technology Catarina, Santa Catarina, Brazil |
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Abstract: | Agriculture is faced with the challenge of providing healthy food for a growing population at minimal environmental cost. 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 reduce water use, greenhouse gas emissions and arsenic (As) levels in rice. Various treatments ranging in frequency and duration of AWD practices were evaluated at three locations over 2 years. Relative to the flooded control treatment and depending on the AWD treatment, yields were reduced by <1–13%; water‐use efficiency was improved by 18–63%, global warming potential (GWP of CH4 and N2O emissions) reduced by 45–90%, and grain As concentrations reduced by up to 64%. 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 remainder of season, similar yields as the flooded control were obtained but reduced water use (18%), GWP (45%) and yield‐scaled GWP (45%); although grain As concentrations were similar or higher. This highlights that multiple environmental benefits can be realized without sacrificing yield but there may be trade‐offs to consider. Importantly, adoption of these practices will require that they are economically attractive and can be adapted to field scales. |
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Keywords: | alternate wetting and drying arsenic greenhouse gas emissions irrigation management
Oryza sativa
sustainable intensification water‐use efficiency |
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