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Legume species identity and soil nitrogen supply determine symbiotic nitrogen‐fixation responses to elevated atmospheric [CO 2 ]
Author(s) -
West Jason B.,
HilleRisLambers Janneke,
Lee Tali D.,
Hobbie Sarah E.,
Reich Peter B.
Publication year - 2005
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2005.01444.x
Subject(s) - nitrogen fixation , legume , nitrogen , ecosystem , fixation (population genetics) , biology , agronomy , dilution , botany , ecology , chemistry , biochemistry , physics , organic chemistry , gene , thermodynamics
Summary• In nitrogen (N)‐limited systems, the response of symbiotic N fixation to elevated atmospheric [CO 2 ] may be an important determinant of ecosystem responses to this global change. Experimental tests of the effects of elevated [CO 2 ] have not been consistent. Although rarely tested, differences among legume species and N supply may be important. • In a field free‐air CO 2 enrichment (FACE) experiment, we determined, for four legume species, whether the effects of elevated atmospheric [CO 2 ] on symbiotic N fixation depended on soil N availability or species identity. Natural abundance and pool‐dilution 15 N methods were used to estimate N fixation. • Although N addition did, in general, decrease N fixation, contrary to theoretical predictions, elevated [CO 2 ] did not universally increase N fixation. Rather, the effect of elevated [CO 2 ] on N fixation was positive, neutral or negative, depending on the species and N addition. • Our results suggest that legume species identity and N supply are critical factors in determining symbiotic N‐fixation responses to increased atmospheric [CO 2 ].