title: Elevated CO2 increases nitrogen rhizodeposition and microbial immobilization of root-derived nitrogen.
abstract: With this study, we aimed to determine how elevated CO(2) affects rhizodeposition and the cycling of rhizodeposited nitrogen (N) in the soil under C(3) and C(4) plants. In addition, we examined how cultivated genotypes of wheat (Triticum turgidum) and maize (Zea mays) responded to elevated CO(2) in comparison with their wild relatives. By constructing an N-transfer experiment we could directly assess cycling of the rhizodeposited N and trace the fate of rhizodeposited N in the soil and in receiver plants. Biomass production, rhizodeposition and cycling of root-borne N in maize genotypes were not affected by elevated CO(2). Elevated CO(2) stimulated above- and below-ground biomass production of the wheat genotypes on average by 38%, and increased rhizodeposition and immobilization of root-derived N on average by 30%. Concurrently, elevated CO(2) reduced mineral (15)N and re-uptake of the root-derived N by 50% in wheat. This study shows that elevated CO(2) may enhance N limitation by increasing N rhizodeposition and subsequent immobilization of the root-derived N.
authors.affiliation: Department of Plant Sciences, University of California-Davis, Davis, CA 95616, USA.|Department of Environmental Sciences, Laboratory of Soil Science and Geology, Wageningen University, 6700 AA Wageningen, the Netherlands.
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: De Graaff
authors.affiliation: Department of Plant Sciences, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Johan
authors.initials: J
authors.lastname: Six
authors.affiliation: Department of Plant Sciences, University of California-Davis, Davis, CA 95616, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Van Kessel
mesh_terms: D001272:Atmosphere; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism* / Q000382:microbiology; D012988:Soil Microbiology; D014908:Triticum / Q000378:metabolism / Q000382:microbiology; D003313:Zea mays / Q000378:metabolism / Q000382:microbiology
chemical_list: D009587:Nitrogen Isotopes; D002245:Carbon Dioxide; D009584:Nitrogen