See more from this Session: General Global Agronomy: II
Wednesday, October 19, 2011: 10:50 AM
Hilton Palacio del Rio, Corte Real DEF, Concourse Level
The effect of elevated carbon dioxide concentration [CO2] on symbiotic nitrogen (N2) fixation by soybean under open-air conditions has not been reported. Two soybean cultivars (Glycine max (L.) Merr. cv. Zhonghuang 13 and cv. Zhonghuang 35) were grown to maturity under ambient (415 ± 16 mmol mol–1) and elevated (550 ± 17 mmol mol–1) [CO2] at the Free-Air Carbon dioxide Enrichment (FACE) experimental facility in a semi-arid region in northern China. Elevated [CO2] increased above- and below-ground biomass by 17% and 16%, respectively, but had no significant effect on the tissue total N and total C concentration at maturity. Elevated [CO2] marginally increased the percentage of N derived from the atmosphere (%Ndfa, estimated by natural abundance) from 59 to 79% for the above-ground parts of Zhonghuang 13, and the amount of N fixed from 1.1 to 1.9 g N plant–1 (16.6 to 27.5 g N m–2), but had no significant effect on either parameter for Zhonghuang 35. It appears that impact of elevated [CO2] on N2 fixation of soybean in this semi-arid region is cultivar dependent and that these differences could be exploited to improve N supply in these cropping systems in future high carbon dioxide atmospheres.
Free-air carbon dioxide enrichment (FACE), symbiotic nitrogen fixation, nodulation, natural abundance, soybean cultivar