|Cheng, Lei -|
|Hu, Shuijin -|
Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 30, 2009
Publication Date: August 5, 2009
Citation: Booker, F.L., Burkey, K.O., Fiscus, E.L., Cheng, L., Hu, S. 2009. Elevated carbon dioxide and ozone effects on above- and belowground growth and decomposition in a no-till soybean-wheat system. Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting Nov 2009. Technical Abstract: Elevated atmospheric carbon dioxide and ozone concentrations often have counteracting influences on many C3 crops depending on the concentration of the gases and sensitivity of the crop although root growth and residue decomposition responses are poorly understood. The objective of this experiment was to determine the separate and combined effects of elevated carbon dioxide and ozone on above- and belowground growth and decomposition in a soybean-wheat no-till system. Plants were treated with either ambient or elevated carbon dioxide (550 µmol mol-1) in combination with charcoal-filtered (CF) air or CF air plus ozone (1.4 x ambient ozone) using open-top field chambers. Results showed that elevated carbon dioxide stimulated soybean and wheat biomass production at harvest by 25%. Soybean and wheat biomass and yield were suppressed by added ozone to a similar extent. Soybean root length at elevated carbon dioxide was similar to the control while it was 45% lower in the added ozone treatment due to lower production and early senescence. In the combined elevated carbon dioxide and ozone treatment, biomass and root length were restored to control or higher levels. The root to shoot ratio was decreased by both elevated carbon dioxide and ozone. After three years, surface litter C mass was higher in the elevated carbon dioxide treatments but similar to the control in the added ozone treatment even though 10% less residue C was added to the system. Results indicated that ozone suppressed the growth-stimulating effects of elevated carbon dioxide concentrations.