Journal ArticleDOI
Separating root and soil microbial contributions to soil respiration: A review of methods and observations
TLDR
In this article, three primary methods have been used to distinguish hetero- versus autotrophic soil respiration including integration of components contributing to in situ forest soil CO2 efflux (i.e., litter, roots, soil), comparison of soils with and without root exclusion, and application of stable or radioactive isotope methods.Abstract:
Forest soil respiration is the sum of heterotrophic (microbes, soil fauna) and auto- trophic (root) respiration. The contribution of each group needs to be understood to evaluate implications of environmental change on soil carbon cycling and sequestration. Three primary methods have been used to distinguish hetero- versus autotrophic soil respiration including: integration of components contributing to in situ forest soil CO2 efflux (i.e., litter, roots, soil), comparison of soils with and without root exclusion, and application of stable or radioactive isotope methods. Each approach has advantages and disadvantages, but isotope based methods provide quantitative answers with the least amount of disturbance to the soil and roots. Pub- lished data from all methods indicate that root/rhizosphere respiration can account for as little as 10 percent to greater than 90 percent of total in situ soil respiration depending on vegetation type and season of the year. Studies which have integrated percent root contribution to total soil respiration throughout an entire year or growing season show mean values of 45.8 and 60.4 percent for forest and nonforest vegetation, respectively. Such average annual values must be extrapolated with caution, however, because the root contribution to total soil respiration is commonly higher during the growing season and lower during the dormant periods of the year. Abbreviations: TScer -t otal soil CO 2 efflux rate; f - fractional root contribution to TS cer; RC - root contribution to TScerread more
Citations
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Journal ArticleDOI
Toward an ecological classification of soil bacteria.
TL;DR: Survey, experimental, and meta-analytical results suggest that certain bacterial phyla can be differentiated into copiotrophic and oligotrophic categories that correspond to the r- and K-selected categories used to describe the ecological attributes of plants and animals.
Journal ArticleDOI
Large-scale forest girdling shows that current photosynthesis drives soil respiration
Peter Högberg,Anders Nordgren,Nina Buchmann,Andy F. S. Taylor,Alf Ekblad,Alf Ekblad,Mona N. Högberg,Gert Nyberg,Mikaell Ottosson-Löfvenius,David Read +9 more
TL;DR: Girdling reduced soil respiration within 1–2 months by about 54% relative to respiration on ungirdled control plots, and that decreases of up to 37% were detected within 5 days, which clearly show that the flux of current assimilates to roots is a key driver of soil resppiration.
Journal ArticleDOI
Elevated CO2 effects on plant carbon, nitrogen, and water relations: six important lessons from FACE
Andrew D. B. Leakey,Elizabeth A. Ainsworth,Elizabeth A. Ainsworth,Carl J. Bernacchi,Carl J. Bernacchi,Alistair Rogers,Alistair Rogers,Stephen P. Long,Donald R. Ort +8 more
TL;DR: Some of the lessons learned from the long-term investment in Free-Air CO(2) Enrichment experiments are described, where many of these lessons have been most clearly demonstrated in crop systems, and have important implications for natural systems.
Journal ArticleDOI
Reduction of forest soil respiration in response to nitrogen deposition
Ivan A. Janssens,Wouter Dieleman,Sebastiaan Luyssaert,Jens-Arne Subke,Markus Reichstein,Reinhart Ceulemans,Philippe Ciais,A. J. Dolman,John Grace,Giorgio Matteucci,Dario Papale,Shilong Piao,Ernst Detlef Schulze,Jianwu Tang,Beverly E. Law +14 more
TL;DR: A meta-analysis suggests that nitrogen deposition impedes organic matter decomposition, and thus stimulates carbon sequestration, in temperate forest soils where nitrogen is not limiting microbial growth as mentioned in this paper, and the concomitant reduction in soil carbon emissions is substantial, and equivalent in magnitude to the amount of carbon taken up by trees owing to nitrogen fertilization.
Journal ArticleDOI
Plant and mycorrhizal regulation of rhizodeposition
TL;DR: Evidence is brought together to show that roots can directly regulate most aspects of rhizosphere C flow either by regulating the exudation process itself or by directly regulating the recapture of exudates from soil.
References
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Journal ArticleDOI
Evidence from chronosequence studies for a low carbon-storage potential of soils
TL;DR: This article used data from chronosequence studies to show that the production of refractory humus substances in soils sequesters only ∼ 0.4 × 1015 g C yr−1 from the atmosphere, accounting for just 0.7% of terrestrial net primary production.
Journal ArticleDOI
Belowground Carbon Allocation in Forest Ecosystems: Global Trends
TL;DR: In this paper, carbon allocation to roots in forest ecosystems is estimated from published data on soil respiration and litterfall, suggesting that above-and belowground production are controlled by the same factors.
Journal ArticleDOI
On the isotopic composition of carbon in soil carbon dioxide
TL;DR: In this paper, the isotopic composition of carbon in soil CO2 differs from that of CO2 in soil-respired CO2, which is very close to the theoretical difference of 4.4%.
Journal ArticleDOI
The fate of carbon in grasslands under carbon dioxide enrichment
Bruce A. Hungate,Bruce A. Hungate,Elisabeth A. Holland,Robert B. Jackson,F. Stuart Chapin,Harold A. Mooney,Christopher B. Field +6 more
TL;DR: In this article, the authors present an annual budget focusing on below-ground carbon cycling for two grassland ecosystems exposed to elevated CO2 concentrations, showing that CO2 doubling increased ecosystem carbon uptake, but greatly increased carbon partitioning to rapidly cycling carbon pools below ground.
Journal ArticleDOI
Belowground cycling of carbon in forests and pastures of eastern Amazonia
Susan E. Trumbore,Eric A. Davidson,Plínio Barbosa de Camargo,Daniel C. Nepstad,Luiz Antonio Martinelli +4 more
TL;DR: In this article, a model of belowground carbon cycling derived from measurements of carbon stocks and fluxes, and constrained using carbon isotopes, is used to predict C fluxes associated with conversion of deep-rooting forests to pasture and subsequent pasture management.