N2 fixation and performance of 12 legume species in a 6-year grassland biodiversity experiment
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Highly variable effects of legumes have been observed in biodiversity experiments, but little is known about plant diversity effects on N2 fixation of legume species. We used the 15N natural abundance method in a non-fertilized regularly mown 6-year biodiversity experiment (Jena Experiment) to quantify N2 fixation of 12 legume species. The proportion of legume N derived from the atmosphere (%Ndfa) differed significantly among legume species. %Ndfa values were lower in 2004 after setting-up the experiment (73 ± 20) than in the later years (2006: 80 ± 16; 2008: 78 ± 12). Increasing species richness had positive effects on %Ndfa in 2004 and 2006, but not in 2008. High biomass production of legumes in 2004 and 2006 declined to lower levels in 2008. In 2006, legume positioning within the canopy best explained variation in %Ndfa values indicating a lower reliance of tall legumes on N2 fixation. In 2008, larger %Ndfa values of legumes were related to lower leaf P concentrations suggesting that the availability of phosphorus limited growth of legumes. In summary, diversity effects on N2 fixation depend on legume species identity, their ability to compete for soil nutrients and light and may vary temporally in response to changing resource availability.
KeywordsBiodiversity Jena Experiment Legumes 15N natural abundance N2 fixation Phosphorus
The Jena Experiment is funded by the German Science Foundation (FOR 456) with support by the University of Jena and the Max Planck Institute for Biogeochemistry and is coordinated by W.W. Weisser. We thank U. Gerighausen, U. Wehmeier and S. Hengelhaupt for technical assistance and all of the people who assisted in maintaining the experiment and harvesting biomass. We acknowledge H. Geilmann, I. Hilke and M. Räßler for stable isotope and elemental analyses.
- Carlsson G, Palmborg C, Huss-Danell K (2006) Discrimination against 15N in three N2-fixing Trifolium species as influenced by Rhizobium strain and plant age. Acta Agric Scand 56:31–38Google Scholar
- Ellenberg H (1988) Vegetation ecology of Central Europe. Cambridge Univ Press, CambridgeGoogle Scholar
- Habekost M (2008) Influence of plant diversity on soil organic carbon storage and microbial transformation of organic carbon in soil. Dissertation. Univ JenaGoogle Scholar
- Kluge G, Müller-Westermeier G (2000) Das Klima ausgewählter Orte der Bundesrepublik Deutschland: Jena. Ber Dtsch Wetterdienstes 213:1–290Google Scholar
- Pate JS (1986) Economy of symbiotic N fixation. In: Givnish TJ (ed) On the economy of plant form and function. Cambridge Univ Press, Cambridge, pp 299–325Google Scholar
- Shearer G, Kohl DH (1986) N2-fixation in field settings: estimations based on natural 15N abundance. Aust J Plant Physiol 13:699–756Google Scholar
- Spehn EM, Scherer-Lorenzen M, Schmid B, Hector A, Caldeira MC, Dimitrakopoulos PG, Finn JA, Jumpponen A, O’Donnovan G, Pereira JS, Schulze E-D, Troumbis AY, Körner C (2002) The role of legumes as a component of biodiversity in a cross-European study of grassland biomass nitrogen. Oikos 98:205–218CrossRefGoogle Scholar
- Spehn EM, Hector A, Joshi J, Scherer-Lorenzen M, Schmid B, Bazeley-White E, Beierkuhnlein C, Caldeira MC, Diemer M, Dimitrakopoulos PG, Finn JA, Freitas H, Giller PS, Good J, Harris R, Högberg P, Huss-Danell K, Jumpponen A, Koricheva J, Leadley PW, Loreau M, Minns A, Mulder CPH, O’Donovan G, Otway SJ, Palmborg C, Pereira JS, Pfisterer AB, Prinz A, Read DJ, Schulze E-D, Siamantziouras A-SD, Terry AC, Troumbis AY, Woodward FI, Yachi S, Lawton JH (2005) Ecosystem effects of biodiversity manipulations in European grasslands. Ecol Monogr 75:37–63CrossRefGoogle Scholar
- Vitousek PM, Field CB (1999) Ecosystem constraints to symbiotic nitrogen fixers: a simple model and its implications. Biogeochemistry 46:179–202Google Scholar