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Living roots magnify the response of soil organic carbon decomposition to temperature in temperate grassland.

Hill PW, Garnett MH, Farrar J, Iqbal Z, Khalid M, Soleman N, Jones DL - Glob Chang Biol (2014)

Bottom Line: Most have attempted this in the absence of plants as the flux of CO2 from root and rhizomicrobial respiration in intact plant-soil systems confounds interpretation of measurements.We compared the effect of a small increase in temperature on respiration from soils without recent plant C with the effect on intact grass swards.We found that for 48 weeks, before acclimation occurred, an experimental 3 °C increase in sward temperature gave rise to a 50% increase in below ground respiration (ca. 0.4 kg C m(-2) ; Q10  = 3.5), whereas mineralisation of older SOC without plants increased with a Q10 of only 1.7 when subject to increases in ambient soil temperature.

View Article: PubMed Central - PubMed

Affiliation: School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK.

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Related in: MedlinePlus

Soil temperature and belowground respiration in the field experiment with 14C content of CO2 respired in field and laboratory. Soil temperature and belowground respiration for control and warmed swards are shown in the upper and middle panels, respectively. Values for the 14C content of respired CO2 are shown on the lower panel. All values are mean ± SEM; n = 3.
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fig01: Soil temperature and belowground respiration in the field experiment with 14C content of CO2 respired in field and laboratory. Soil temperature and belowground respiration for control and warmed swards are shown in the upper and middle panels, respectively. Values for the 14C content of respired CO2 are shown on the lower panel. All values are mean ± SEM; n = 3.

Mentions: Heating tape (RS Components, Corby, UK) was inserted in the soil of six 0.5 × 0.5 m portions of grass sward at a depth of 5 cm and at 5 cm intervals horizontally. To minimise disturbance, soil was cut with a knife and heating tape was pushed into the incision. A 4 cm long temperature probe was inserted to a depth of 7 cm between two sections of heating tape close to the centre of each plot. These probes were attached to RESOL DeltaSol Pro temperature differential regulators (RESOL, Hattingen, Germany). Three probes were used to determine ambient soil temperature (control plots) and three were used to measure the temperature in warmed plots. Polypropylene board was inserted into the soil around the plots to a depth of 20 cm to prevent lateral movement of CO2 from outside the treatment area. Swards were allowed to recover from disturbance for 6 weeks before the start of treatments. After 6 weeks, power was applied to the heating tape in three plots. The soil temperature of warmed plots was maintained at 3.0 ± 0.04 °C (mean ± SEM; n = 49; Fig.1) above controls. To avoid overheating of soil and plants close to the heating tape and/or the generation of a temperature gradient, the current supplied to the heating tape was restricted to ca. 0.2 A (240 V). Measurements with a 2 mm diameter temperature probe from 0.5 to 2.5 cm from the tape could detect no temperature gradient. The treatment was maintained continuously for 80 weeks. During this period, swards were not cut or fertilised and grazing animals were excluded by fencing.


Living roots magnify the response of soil organic carbon decomposition to temperature in temperate grassland.

Hill PW, Garnett MH, Farrar J, Iqbal Z, Khalid M, Soleman N, Jones DL - Glob Chang Biol (2014)

Soil temperature and belowground respiration in the field experiment with 14C content of CO2 respired in field and laboratory. Soil temperature and belowground respiration for control and warmed swards are shown in the upper and middle panels, respectively. Values for the 14C content of respired CO2 are shown on the lower panel. All values are mean ± SEM; n = 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4365897&req=5

fig01: Soil temperature and belowground respiration in the field experiment with 14C content of CO2 respired in field and laboratory. Soil temperature and belowground respiration for control and warmed swards are shown in the upper and middle panels, respectively. Values for the 14C content of respired CO2 are shown on the lower panel. All values are mean ± SEM; n = 3.
Mentions: Heating tape (RS Components, Corby, UK) was inserted in the soil of six 0.5 × 0.5 m portions of grass sward at a depth of 5 cm and at 5 cm intervals horizontally. To minimise disturbance, soil was cut with a knife and heating tape was pushed into the incision. A 4 cm long temperature probe was inserted to a depth of 7 cm between two sections of heating tape close to the centre of each plot. These probes were attached to RESOL DeltaSol Pro temperature differential regulators (RESOL, Hattingen, Germany). Three probes were used to determine ambient soil temperature (control plots) and three were used to measure the temperature in warmed plots. Polypropylene board was inserted into the soil around the plots to a depth of 20 cm to prevent lateral movement of CO2 from outside the treatment area. Swards were allowed to recover from disturbance for 6 weeks before the start of treatments. After 6 weeks, power was applied to the heating tape in three plots. The soil temperature of warmed plots was maintained at 3.0 ± 0.04 °C (mean ± SEM; n = 49; Fig.1) above controls. To avoid overheating of soil and plants close to the heating tape and/or the generation of a temperature gradient, the current supplied to the heating tape was restricted to ca. 0.2 A (240 V). Measurements with a 2 mm diameter temperature probe from 0.5 to 2.5 cm from the tape could detect no temperature gradient. The treatment was maintained continuously for 80 weeks. During this period, swards were not cut or fertilised and grazing animals were excluded by fencing.

Bottom Line: Most have attempted this in the absence of plants as the flux of CO2 from root and rhizomicrobial respiration in intact plant-soil systems confounds interpretation of measurements.We compared the effect of a small increase in temperature on respiration from soils without recent plant C with the effect on intact grass swards.We found that for 48 weeks, before acclimation occurred, an experimental 3 °C increase in sward temperature gave rise to a 50% increase in below ground respiration (ca. 0.4 kg C m(-2) ; Q10  = 3.5), whereas mineralisation of older SOC without plants increased with a Q10 of only 1.7 when subject to increases in ambient soil temperature.

View Article: PubMed Central - PubMed

Affiliation: School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, LL57 2UW, UK.

Show MeSH
Related in: MedlinePlus