Abstract
(1) Background: Elevated atmospheric CO2 concentration affects the growth and development of the rice crop. In Southern Brazil, rice is traditionally produced with continuous irrigation, implying a significant amount of water used. Besides, continuous flooding favors the uptake of toxic elements such as arsenic (As) and cadmium (Cd). In this work, one Brazilian rice cultivar (IRGA 424) was tested for the effects of elevated CO2 concentration and different water regimes on rice yield, and As and Cd accumulation in grain. (2) Methods: Rice was grown in two CO2 concentrations (400 and 700 µmol mol−1) and two irrigation regimes (continuous and intermittent). It was evaluated the number of tillers, plant height, aboveground dry weight (ADW), water use efficiency (WUE), rice yield components, and As and Cd concentration in rice grain. (3) Results: Rice plants were taller and had a higher WUE when cultivated at e[CO2]. The ADW and the rice yield component were not affected by CO2 levels nor water regimes. Intermittent flood regimes had a lower average As concentration. The Cd concentration in the samples in both growing seasons and all treatments was below the limit of quantitation (8.76 μg kg−1). (4) Conclusions: Enhanced CO2 concentration did not affect rice yield, increased the WUE, and reduced As concentration in grains. Regarding water management, the intermittent regime enhanced WUE and promoted a reduction in As concentration in grains.
Highlights
Rice (Oryza sativa L.) is a vitally important crop whose role in global food security is remarkable [1]
For the 2018/19 growing season, the average tiller number for the intermittent flooding treatment was higher under e[CO2] than a[CO2]
This study showed that the rice cultivar IRGA 424 RI had higher growth under e[CO2], but there was no increase in grain yield
Summary
Rice (Oryza sativa L.) is a vitally important crop whose role in global food security is remarkable [1]. Brazil and the U.S are world rice exporters, with more than 60% of the total rice produced in the Americas [3]. This important crop is threatened by climate change and by the declines in freshwater available. Agriculture will experience some of the most significant impacts of climate change due to its dependence on stable temperatures and reliable rainfall, being impacted by the increasing atmospheric concentration of CO2 ([CO2]) [4,5]. Extensive efforts are underway to measure and determine ways to mitigate the impact of climate change on agricultural production [7,8]
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