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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Book ChapterDOI
Evaluation of the use of a model rhizodeposition technique to separate root and microbial respiration in soil
TL;DR: A model rhizodeposition technique to estimate the root and microbial components of 14C soil/root respiration in pulse-labelling experiments is described and the use of the method in rhizosphere carbon budget estimations is evaluated.
Journal ArticleDOI
Estimation of carbon allocation to the roots from soil respiration measurements of oil palm
TL;DR: In this article, the authors measured CO2 flux from the soil under oil palms in southern Benin and determined carbon allocation to the roots, and found that root respiration accounted for 30% of the efflux when at field capacity and 80% when the soil was dry with a pF close to 4.2.
Journal ArticleDOI
The contribution of plant C to soil CO2 measured using δ13C
Journal ArticleDOI
Carbon fluxes in the rhizosphere of sweet chestnut seedlings (Castanea sativa) grown under two atmospheric CO2 concentrations : 14C partitioning after pulse labelling
TL;DR: Partitioning of 14C was assessed in sweet chestnut seedlings (Castanea sativa mill) grown in ambient and elevated atmospheric [CO2] environments during two vegetative cycles as mentioned in this paper.
Journal ArticleDOI
Litter input, litter decomposition and the evolution of carbon dioxide in a beech woodland-Wytham woods, Oxford.
TL;DR: Tree litter fall was measured from May 1969 to April 1973 and varied between 205 and 388 g m-2a-1 and soil metabolism, measured as carbon dioxide evolution, showed a significant correlation with temperature and during 1973–1974 had a dry matter equivalent of 342 gm-2 a-1.