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| Improvement and performance of open-top chambers used for simulating elevated CO2 under field conditions |
| Received:January 15, 2017 |
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| KeyWord:elevated CO2;open-top chamber;simulation in situ;improved effect;spring maize |
| Author Name | Affiliation | E-mail | | GUO Yan-liang | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Environment and Resources, Northwest A&F University, Yangling 712100, China | | | WANG Xiao-lin | College of Environment and Resources, Northwest A&F University, Yangling 712100, China | | | ZHANG Xiao-yuan | College of Environment and Resources, Northwest A&F University, Yangling 712100, China | | | WANG Li-mei | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Environment and Resources, Northwest A&F University, Yangling 712100, China | sdwanglimei@163.com | | ZHENG Ji-yong | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Environment and Resources, Northwest A&F University, Yangling 712100, China | | | LI Shi-qing | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Environment and Resources, Northwest A&F University, Yangling 712100, China | |
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| Abstract: |
| In order to improve the applicability and accuracy of Open-Top Chambers(OTCs) in simulating the effects of elevated CO2 on crop growth and yield under field conditions, the open-top area of the chamber was increased, the shape of the bottom was modified from octagonal to square, a new material was used for the chamber walls, and fans were installed in the chamber to increase air circulation. These improved OTCs were used for simulating elevated CO2 concentration in spring maize farmland in 2015 and 2016. The chamber measured 4.0 m × 4.0 m × 3.0 m(length × width × height) and was equipped with an automated CO2 delivery system designed to maintain the CO2 concentration at 700 μmol·mol-1 in the chamber. During the maize growth period, CO2 concentration, air temperature, and relative humidity were measured automatically every 10 minutes both inside and outside the OTCs. The CO2 concentration, air temperature, and relative humidity inside the OTCs were compared to those under natural conditions, and the simulation performance was analyzed. The results demon strated that the CO2 concentration could be well controlled by the improved OTC system. The deviation from the targeted CO2 concentration ranged from -17.2 μmol·mol-1 to 0.2 μmol·mol-1 in 2015 and from -5.4 μmol·mol-1 to 0.1 μmol·mol-1 in 2016. The mean air temperature inside the OTCs was 0.8 ℃ higher than that of the natural air during daytime in 2015(P<0.05), and no significant difference in such was observed for 2016. There was no significant difference in relative humidity between inside and outside of the chambers(P>0.05). Our results indicated that the improved OTC has stable performance and high accuracy and can be used for future field simulation experiments. |
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