CO₂ and soil water potential as regulators of the growth and N fraction derived from fixation of a legume in tallgrass prairie communities
Background and Aims CO₂ enrichment may increase N input to ecosystems by increasing N₂ fixation, but the fixation-CO₂ response depends on factors such as soil water availability that are influenced by soil properties. Methods We used the δ¹⁵N natural abundance method to estimate the proportion of N...
| Veröffentlicht in: | Plant and Soil. - Springer Science + Business Media. - 409(2016), 1/2, Seite 361-370 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2016
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| Zugriff auf das übergeordnete Werk: | Plant and Soil |
| Schlagworte: | Applied sciences Biological sciences Physical sciences |
| Zusammenfassung: | Background and Aims CO₂ enrichment may increase N input to ecosystems by increasing N₂ fixation, but the fixation-CO₂ response depends on factors such as soil water availability that are influenced by soil properties. Methods We used the δ¹⁵N natural abundance method to estimate the proportion of N in the legume Desmanthus illinoensis that was derived from N₂ fixation following 2-8 years of growth along a subambient to elevated CO₂ gradient. Desmanthus was grown in tallgrass prairie communities on each of three soils of differing texture. Results Only on a clay soil was it possible to calculate fixation (Nfix; g N m⁻²). The fraction of legume N derived from fixation (Ndfa) decreased by 20 % as CO₂ increased from subambient to elevated concentrations. The negative effect of reduced Ndfa on Nfix was obscured by variation in Desmanthus production along the CO₂ gradient that was positively linked to the ANPP-CO₂ response of communities. Across soils, legume production was negatively correlated with soil water potential to 0.3 m depth (ψsoil). Conclusions Nfix in grasslands may depend primarily on ψsoil as influenced by soil hydrological properties. CO₂ enrichment may reduce Nfix during years in which the legume-CO₂ and related ANPP-CO₂ response is small by depressing Ndfa. |
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| ISSN: | 15735036 |