Tuesday, August 5, 2008: 8:20 AM
102 E, Midwest Airlines Center
Lei Cheng1, Jianguo Zhu2, Gaiping Chen2, Xunhua Zheng3, Neung-Hwan Oh4, Thomas W Rufty5, Daniel Richter6 and Shuijin Hu7, (1)Life Sciences, Zhejiang University, Hangzhou, China, (2)Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China, (3)Institute of Atmospheric Physics, Chinese Academy of Sciences, Bejing, China, (4)Forestry and Environmental Studies, Yale University, New Haven, CT, (5)Department of Plant Pathology, North Carolina State University, Raleigh, NC, (6)Environment, Duke University, Durham, NC, (7)Plant Pathology, North Carolina State University, Raleigh, NC
Background/Question/Methods Elevated atmospheric CO2 generally stimulates plant photosynthesis and nutrient uptake, modifying the local and global cycling of bioactive elements. Although nutrient cations affect the long-term productivity and carbon balance of terrestrial ecosystems, little is known about the effect of CO2 enrichment on cation availability in soil. Utilizing free-air CO2 enrichment facilities, we conducted two field experiments to investigate the effect of elevated CO2 (ambient + 200 μmol mol-1) on plant growth, soil solution chemistry and microbial activities in the rice-wheat rotation system.
Results/Conclusions
Elevated CO2 enhanced organic C allocation belowground and stimulated root and microbial respiration. Elevated CO2 significantly increased Ca2+, Mg2+, Fe2+ and Mn2+ in soil solutions. While enhancing cation uptake of rice plants, elevated CO2 also increased net H+ excretion from roots. These results indicate that over the short term, elevated CO2 may stimulate cation release from soils and plant growth. Over the long term, however, CO2-induced cation release may increase cation losses and depletion, constraining the productivity of terrestrial ecosystems
