The influence of elevated CO2 and soil depth on rhizosphere activity and nutrient availability in a mature Eucalyptus woodland
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Published:2023-02-02
Issue:3
Volume:20
Page:505-521
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ISSN:1726-4189
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Container-title:Biogeosciences
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language:en
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Short-container-title:Biogeosciences
Author:
Pihlblad JohannaORCID, Andresen Louise C.ORCID, Macdonald Catriona A., Ellsworth David S., Carrillo Yolima
Abstract
Abstract. Elevated carbon dioxide (eCO2) in the atmosphere increases forest biomass productivity but only where soil nutrients, particularly nitrogen (N) and phosphorus (P), are not limiting growth. eCO2, in turn, can impact rhizosphere nutrient availability. Our current understanding of nutrient cycling under eCO2 is mainly derived from surface soil, leaving mechanisms of the impact of eCO2 on rhizosphere nutrient availability at deeper depths unexplored. To investigate the influence of eCO2 on nutrient availability in soil at depth, we studied various C, N, and P pools (extractable, microbial biomass, total soil C and N, and mineral-associated P) and nutrient cycling processes (enzyme activity and gross N mineralisation) associated with C, N, and P cycling in both bulk and rhizosphere soil at different depths at the Free Air CO2 enrichment facility in a native Australian mature Eucalyptus woodland (EucFACE) on a nutrient-poor soil. We found decreasing nutrient availability and gross N mineralisation with depth; however, this depth-associated decrease was reduced under eCO2, which we suggest is due to enhanced root influence. Increases in available PO43-, adsorbed P, and the C : N and C : P ratio of enzyme activity with depth were observed. We conclude that the influences of roots and of eCO2 can affect available nutrient pools and processes well beyond the surface soil of a mature forest ecosystem. Our findings indicate a faster recycling of nutrients in the rhizosphere, rather than additional nutrients becoming available through soil organic matter (SOM) decomposition. If the plant growth response to eCO2 is reduced by the constraints of nutrient limitations, then the current results would call to question the potential for mature tree ecosystems to fix more C as biomass in response to eCO2. Future studies should address how accessible the available nutrients at depth are to deeply rooted plants and if fast recycling of nutrients is a meaningful contribution to biomass production and the accumulation of soil C in response to eCO2.
Funder
Australian Research Council Svenska Forskningsrådet Formas
Publisher
Copernicus GmbH
Subject
Earth-Surface Processes,Ecology, Evolution, Behavior and Systematics
Reference86 articles.
1. Achat, D. L., Augusto, L., Gallet-Budynek, A., and Loustau, D.: Future
challenges in coupled C–N–P cycle models for terrestrial ecosystems under
global change: a review, Biogeochemistry, 131, 173–202,
https://doi.org/10.1007/s10533-016-0274-9, 2016. 2. Adeleke, R., Nwangburuka, C., and Oboirien, B.: Origins, roles and fate of
organic acids in soils: A review, South Afr. J. Bot., 108,
393–406, https://doi.org/10.1016/j.sajb.2016.09.002, 2017. 3. Ainsworth, E. A. and Long, S. P.: What have we learned from 15 years of
free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of
photosynthesis, canopy properties and plant production to rising CO2, New
Phytol., 165, 351–372,
https://doi.org/10.1111/j.1469-8137.2004.01224.x, 2005. 4. Allison, S. D. and Vitousek, P. M.: Responses of extracellular enzymes to
simple and complex nutrient inputs, Soil Biol. Biochem., 37,
937–944, https://doi.org/10.1016/j.soilbio.2004.09.014, 2005. 5. Andresen, L. C., Carrillo, Y., Macdonald, C. A., Castañeda-Gómez,
L., Bodé, S., and Rütting, T.: Nitrogen dynamics after two years of
elevated CO2 in phosphorus limited Eucalyptus woodland, Biogeochemistry, 150, 297–312,
https://doi.org/10.1007/s10533-020-00699-y, 2020.
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