Temperature sensitivity of organic matter decomposition in two boreal forest soil profiles

Karhu, Kristiina; Fritze, Hannu; Tuomi, Mikko; Vanhala, Pekka; Spetz, Peter; Kitunen, Veikko; Liski, Jari

doi:10.1016/j.soilbio.2009.10.002

Cited by 134 publications

(84 citation statements)

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“…It is explicable that the original hydrophobicity of the manure has a potentially important effect on initiation of SOM decomposition in the amended samples. According to chemical kinetic theory, decomposition of recalcitrant organic substrates has higher activation energy (Karhu et al, 2010, and references therein). Hydrophobic organic compounds that are considered to be recalcitrant (González-Pérez et al, 2002) would require higher activation energy, and thereby can slow down the initiation of the organic matter decomposition process in originally hydrophobic CE amended samples.…”

Section: Resultsmentioning

confidence: 99%

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Leelamanie

2014

Journal of Hydrology and Hydromechanics

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Abstract:The wetting rate of soil is a measure of water repellency, which is a property of soils that prevents water from wetting or penetrating into dry soil. The objective of the present research was to examine the initial water repellency of organic manure amended soil, and its relation to the soil organic matter (SOM) depletion rates in the laboratory. Soil collected from the Wilpita natural forest, Sri Lanka, was mixed with organic manure to prepare soil samples with 0, 5, 10, 25, and 50% organic manure contents. Locally available cattle manure (CM), goat manure (GM), and Casuarina equisetifolia leaves (CE) were used as the organic manure amendments. Organic matter content of soils was measured in 1, 3, 7, 14, and 30 days intervals under the laboratory conditions with 74±5% relative humidity at 28±1°C. Initial water repellency of soil samples was measured as the wetting rates using the water drop penetration time (WDPT) test. Initial water repellency increased with increasing SOM content showing higher increasing rate for hydrophobic CE amended samples compared with those amended with CM and GM. The relation between water repellency and SOM content was considered to be governed by the original hydrophobicities of added manures. The SOM contents of all the soil samples decreased with the time to reach almost steady level at about 30 d. The initial SOM depletion rates were negatively related with the initial water repellency. However, all the CE amended samples initially showed prominent low SOM depletion rates, which were not significantly differed with the amended manure content or the difference in initial water repellency. It is explicable that the original hydrophobicity of the manure as well has a potentially important effect on initiation of SOM decomposition. In contrast, the overall SOM depletion rate can be attributed to the initial water repellency of the manure amended sample, however, not to the original hydrophobicity of the amended manure. Hydrophobic protection may prevent rapid microbial decomposition of SOM and it is conceivable that hydrophobic substances in appropriate composition may reduce organic matter mineralization in soil. These results suggest the contribution of hydrophobic organic substances in bioresistance of SOM and their long-term accumulation in soils.

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Section: Resultsmentioning

confidence: 99%

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Leelamanie

2014

Journal of Hydrology and Hydromechanics

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“…In general, with increasing soil depth, organic matter becomes increasingly chemically recalcitrant (Rumpel et al 2002;Lorenz and Lal 2005;Spielvogel et al 2008). Therefore, the temperature sensitivity of SOC decomposition should theoretically increase with depth (Lomander et al 1998;Fierer et al 2003;Karhu et al 2010). However, our results did not support this prediction, suggesting mechanisms other than chemical recalcitrance are needed to explain our results.…”

Section: Discussionmentioning

confidence: 99%

“…However, previous studies have shown inconsistent patterns of Q 10 values of soil respiration with soil depth. Increase (Lomander et al 1998;Fierer et al 2003;Jin et al 2008;Karhu et al 2010), decrease (Winkler et al 1996;MacDonald et al 1999;Gillabel et al 2010), or no changes (Fang et al 2005;Leifeld and Fuhrer 2005;Rey et al 2008) in apparent Q 10 values with increasing soil depth have been observed in different studies. Much of the variation in the apparent temperature sensitivity of SOC decomposition may be related to the fact that labile substrate availability is often unaccounted for in these studies Gershenson et al 2009;Conant et al 2011).…”

Section: Introductionmentioning

confidence: 96%

Labile substrate availability controls temperature sensitivity of organic carbon decomposition at different soil depths

et al. 2015

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The decomposition of soil organic carbon (SOC) is intrinsically sensitive to temperature. However, the degree to which the temperature sensitivity of SOC decomposition (as often measured in Q 10 value) varies with soil depth and labile substrate availability remain unclear. This study explores (1) how the Q 10 of SOC decomposition changes with increasing soil depth, and (2) how increasing labile substrate availability affects the Q 10 at different soil depths. We measured soil CO 2 production at four temperatures (6, 14, 22 and 30°C) using an infrared CO 2 analyzer.Treatments included four soil depths (0-20, 20-40, 40-60 and 60-80 cm), four sites (farm, redwood forest, ungrazed and grazed grassland), and two levels of labile substrate availability (ambient and saturated by adding glucose solution). We found that Q 10 values at ambient substrate availability decreased with increasing soil depth, from 2.0-2.4 in 0-20 cm to 1.5-1.8 in 60-80 cm. Moreover, saturated labile substrate availability led to higher Q 10 in most soil layers, and the increase in Q 10 due to labile substrate addition was larger in subsurface soils (20-80 cm) than in surface soils (0-20 cm). Further analysis showed that microbial biomass carbon (MBC) and SOC best explained the variation in Q 10 at ambient substrate availability across ecosystems and depths (R 2 = 0.37, P \ 0.001), and MBC best explained the variation in the change of Q 10 between control and glucose addition treatment (R 2 = 0.14, P = 0.003).Xueyong Pang and Biao Zhu contributed equally to this work.

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“…At coniferous sites the amount of recalcitrant material is higher (Landsberg and Gower, 1997;Wang et al, 2006) than at all other sites investigated. Temperature sensitivity of soil respiration increases with substrate recalcitrance as long as environmental constraints are not limiting decomposition (Conant et al, 2008;Hartley and Ineson, 2008;Karhu et al, 2010;Lützow and Kögel-Knabner, 2009;Zimmermann and Bird, 2012) because of the higher number of steps needed for decomposition of more complex substrates. Also, according to kinetic theory, the temperature sensitivity of decomposition increases with increasing molecular complexity of the substrate due to the higher activation energy of recalcitrant substrates (Hartley and Ineson, 2008;Vanhala et al, 2008).…”

Section: Temperature Sensitivitymentioning

confidence: 99%

Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

Gritsch

Zimmermann

Zechmeister‐Boltenstern

2015

Biogeosciences

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Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO 2 ) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO 2 . In order to assess CO 2 emissions from diverse European soils with different land-use types and climate (soil moisture and temperature), we conducted a laboratory incubation experiment.Emission measurements of CO 2 under controlled conditions were conducted using soil monoliths of nine sites from a European flux network (ÉCLAIRE). The sites are located all over Europe -from the United Kingdom in the west to Ukraine in the east, and from Italy in the south to Finland in the north -and can be separated according to four land-use types (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory in a two-way factorial design, with temperature (5, 10, 15, 20 and 25 • C) and water-filled pore space (WFPS; 5, 20, 40, 60 and 80 %) as the independent variables, while CO 2 flux was the response variable. The latter was measured with an automated laboratory incubation measurement system.Land use generally had a substantial influence on carbon dioxide fluxes, with the order of CO 2 emission rates of the different land-use types being grassland > peatland > forest/arable land (P < 0.001). CO 2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO 2 emissions between 40 and 70 % WFPS and a positive relationship between CO 2 emissions and temperature. The relationship between temperature and CO 2 emissions could be well described by a Gaussian model. Q 10 values ranged between 0.86 and 10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q 10 was very low. In addition, under cold temperatures Q 10 varied with moisture contents, indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. At both coniferous forest sites we found a strong increase in the temperature sensitivity at a moisture range between 20 and 40 % WFPS.We developed a new approach to calculate moisture sensitivity (MS) of CO 2 efflux. MS was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO 2 efflux and temperature for both arable lands.

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Temperature sensitivity of organic matter decomposition in two boreal forest soil profiles

Cited by 134 publications

References 50 publications

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Labile substrate availability controls temperature sensitivity of organic carbon decomposition at different soil depths

Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

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Temperature sensitivity of organic matter decomposition in two boreal forest soil profiles

Cited by 134 publications

References 50 publications

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

Labile substrate availability controls temperature sensitivity of organic carbon decomposition at different soil depths

Interdependencies between temperature and moisture sensitivities of CO&lt;sub&gt;2&lt;/sub&gt; emissions in European land ecosystems

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Product

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Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems