Abstract
Rice is a staple food and primary source of calories for much of the world. However, rice can be a dietary source of toxic metal(loid)s to humans, and its cultivation creates atmospheric greenhouse gas emissions and requires high water use. Because rice production consumes a significant amount of natural resources and is a large part of the global agricultural economy, increasing its sustainability could have substantial societal benefits. There are opportunities for more sustainable field production through a combination of silicon (Si) management and conservation irrigation practices. As a Si-rich soil amendment, rice husks can limit arsenic and cadmium uptake, while also providing plant vigor in drier soil conditions. Thus, husk addition and conservation irrigation may be more effective to attenuate the accumulation of toxic metal(loid)s, manage water usage and lower climate impacts when implemented together than when either is implemented separately. This modified field production system would take advantage of rice husks, which are an underutilized by-product of milled rice that is widely available near rice farm sites, and have ~10% Si content. Husk application could, alongside alternate wetting and drying or furrow irrigation management, help resolve multiple sustainability challenges in rice production: (1) limit arsenic and cadmium accumulation in rice; (2) minimize greenhouse gas emissions from rice production; (3) decrease irrigation water use; (4) improve nutrient use efficiency; (5) utilize a waste product of rice processing; and (6) maintain plant-accessible soil Si levels. This review presents the scientific basis for a shift in rice production practices and considers complementary rice breeding efforts. It then examines socio-technical considerations for how such a shift in production practices could be implemented by farmers and millers together and may bring rice production closer to a bio-circular economy. This paper's purpose is to advocate for a changed rice production method for consideration by community stakeholders, including producers, millers, breeders, extension specialists, supply chain organizations, and consumers, while highlighting remaining research and implementation questions.
Highlights
Rice (Oryza sativa L.) is a staple food for half of the global population (Seck et al, 2012), yet its production has several potential undesirable outcomes
We propose that combined AWD and Si management is beneficial, as rice husk amendments may decrease As uptake and alleviate some of the unwanted side effects of the AWD practice
We suggest that further research across the rice production system, including farm and mill activities and processes, and user co-designed decision-support tools are both needed to optimize water management and amendment strategies that balance As and Cd uptake, CH4 and N2O emissions, harvest yield, and farm and supply chain management
Summary
Rice (Oryza sativa L.) is a staple food for half of the global population (Seck et al, 2012), yet its production has several potential undesirable outcomes. The introduction of oxic conditions during the rice growth cycle in AWD management increases the average soil redox potential, thereby decreasing CH4 production and decreasing As availability in the soil and accumulation by the plant (Linquist et al, 2015; Chou et al, 2016; Das et al, 2016). Developing rice varieties with increased tolerance to water deficits would decrease risk of yield losses and could allow extended drying times during AWD to further decrease irrigation costs, CH4 emissions, and grain As accumulation. Husk addition may provide soil health benefits that can benefit rice production in the long-term and should be further investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
