title: Atmospheric CO2 enrichment facilitates cation release from soil.
abstract: Atmospheric CO(2) enrichment 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 CO(2) enrichment on cation availability in soil. In this study, we present evidence for a novel mechanism of CO(2)-enhancement of cation release from soil in rice agricultural systems. Elevated CO(2) increased organic C allocation belowground and net H(+) excretion from roots, and stimulated root and microbial respiration, reducing soil redox potential and increasing Fe(2+) and Mn(2+) in soil solutions. Increased H(+), Fe(2+), and Mn(2+) promoted Ca(2+) and Mg(2+) release from soil cation exchange sites. These results indicate that over the short term, elevated CO(2) may stimulate cation release from soil and enhance plant growth. Over the long-term, however, CO(2)-induced cation release may facilitate cation losses and soil acidification, negatively feeding back to the productivity of terrestrial ecosystems.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: L
authors.initials: L
authors.lastname: Cheng
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.forename: G
authors.initials: G
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.forename: N-H
authors.initials: NH
authors.lastname: Oh
authors.forename: T W
authors.initials: TW
authors.lastname: Rufty
authors.forename: D deB
authors.initials: Dd
authors.lastname: Richter
authors.forename: S
authors.initials: S
authors.lastname: Hu
mesh_terms: D000693:Anaerobiosis; D001272:Atmosphere / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D002412:Cations / Q000737:chemistry; D019069:Cell Respiration; D012275:Oryza / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012987:Soil; D012988:Soil Microbiology
chemical_list: D002412:Cations; D012987:Soil; D002245:Carbon Dioxide