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
Responses of Soils to Climate Change
TL;DR: In this paper, the effects of climate on carbon dynamics in soils through interactions of vegetation, topography, soil physicochemical conditions and parent material are considered, which show that the carbon pools formed in cold soils are susceptible to increased mineralization rates if soil temperatures increase.
Journal ArticleDOI
Below-ground respiratory responses of sugar maple and red maple saplings to atmospheric CO2 enrichment and elevated air temperature
TL;DR: In this article, the authors examined the below-ground respiratory responses of sugar maple (Acer saccharum Marsh.) and red maple seedlings to elevated atmospheric [CO2] and temperature.
Book ChapterDOI
The Role of Soil Invertebrates in Turnover of Organic Matter and Nutrients
TL;DR: Substantial proportions of organic substances which originate in plants or animals eventually reach the soil, where they may remain for only a few hours or days if they are readily decomposable or as long as several decades if they decay slowly.
Book ChapterDOI
Soil pCO 2 , soil respiration, and root activity in CO 2 - fumigated and nitrogen-fertilized ponderosa pine
Dale W. Johnson,Donn Geisinger,Roger F. Walker,John Newman,James M. Vose,Katherine Elliot,Timothy Ball +6 more
TL;DR: In this paper, the effects of CO2 and N treatments on soil pCO2, calculated CO2 efflux, root biomass and soil carbon in open-top chambers planted with Pinus ponderosa seedlings were described.
Journal ArticleDOI
Root respiration rate before and just after clear-felling in a mature, deciduous, broad-leaved forest
Abstract: Soil respiration was measured throughout the year (June 1992 to May 1993) in a mature, deciduous, broad-leaved forest and an adjacent, clear-felled stand which was made in November 1991, in Hiroshima Prefecture, west Japan. The same soil temperature and soil moisture content as those in the forest stand were maintained in two frame boxes covered with sheets of white netting in the clear-felled stand to observe soil respiration. A herbicide was applied to the cut end of all stumps in one of the two frame boxes in order to kill the root system. There was no significant difference in the aboveground biomass and soil environmental conditions between the forest and the frame boxes in the clear-felled stands. The difference in soil respiration rate between the forest and the frame box, in which the root system was killed by the herbicide, was considered to be due largely to the contribution of root respiration. Taking into consideration CO2 evolution due to the decomposition of roots killed and the change in A0 layer respiration rate after clear-felling, the proportion of root respiration to the total soil respiration before clear-felling was estimated to be 51% annually, which coincides closely with those values estimated previously in mature forests by other methods. The difference in the soil respiration rate between the two frame boxes (one with killed roots and the other with undisturbed roots) suggested that the annual root respiration rate just after clear-felling dropped to about two-thirds (70%) of that before clear-felling.