Changes in water extractable organic matter (WEOM) in a calcareous soil under field conditions with time and soil depth

“…It is likely the surface soil layers contain more energy-rich, plant-derived compounds, which may decline with depth in relation to microbially-derived compounds (Baldock and Skjemstad, 2000;Kramer and Gleixner, 2008;Spielvogel et al, 2008;Hassouna et al, 2010;Rumpel and KogelKnabner, 2011;Gabor et al, 2014). Microbial polysaccharides tend to be nutrient-rich and less energy-dense (K€ ogel-Knabner, 2002).…”

Section: Biological Stability and Energetics Of Som With Depthmentioning

confidence: 99%

Relating the biological stability of soil organic matter to energy availability in deep tropical soil profiles

Stone

Plante

2015

Soil Biology and Biochemistry

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“…Soil organic matter (SOM) consists of compounds of vastly different structures and properties. It is commonly perceived that the fraction of less reactive and more recalcitrant organic matter increases with increasing soil depth, meaning that the organic matter at depth is less biodegradable and has more complicated structure than the organic matter at surface (Rumpel et al 2002;Spielvogel et al 2008;Hassouna et al 2010). Kinetic theory predicts that the intrinsic temperature sensitivity of decomposition increases with increasing recalcitrance of the carbon compounds (Bosatta and Ǻ gren 1999).…”

Section: Introductionmentioning

confidence: 99%

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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Changes in water extractable organic matter (WEOM) in a calcareous soil under field conditions with time and soil depth

Cited by 83 publications

References 60 publications

Geochemical mapping of organic carbon in stalagmites using liquid-phase and solid-phase fluorescence

Geochemical mapping of organic carbon in stalagmites using liquid-phase and solid-phase fluorescence

Relating the biological stability of soil organic matter to energy availability in deep tropical soil profiles

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

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