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Updated: Jul 17, 2026

Design and Construction of an Experimental Setup to Enhance Mineral Weathering through the Activity of Soil Organisms
Published on: November 10, 2023
Elevated CO2 increases nitrogen rhizodeposition and microbial immobilization of root-derived nitrogen
Marie-Anne De Graaff1,2, Johan Six1, Chris Van Kessel1
1Department of Plant Sciences, University of California-Davis, Davis, CA 95616, USA.
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.
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