The Temperature Sensitivity (Q10) of Soil Respiration: Controlling Factors and Spatial Prediction at Regional Scale Based on Environmental Soil Classes

Abstract

The temperature sensitivity of heterotrophic soil respiration is crucial for modeling carbon dynamics but it is variable. Presently, however, most models employ a fixed value of 1.5 or 2.0 for the increase of soil respiration per 10°C increase in temperature (Q10). Here we identified the variability of Q10 at a regional scale (Rur catchment, Germany/Belgium/Netherlands). We divided the study catchment into environmental soil classes (ESCs), which we define as unique combinations of land use, aggregated soil groups, and texture. We took nine soil samples from each ESC (108 samples) and incubated them at four soil moisture levels and five temperatures (5–25°C). We hypothesized that Q10 variability is controlled by soil organic carbon (SOC) degradability and soil moisture and that ESC can be used as a widely available proxy for Q10, owing to differences in SOC degradability. Measured Q10 values ranged from 1.2 to 2.8 and were correlated with indicators of SOC degradability (e.g., pH, r = −0.52). The effect of soil moisture on Q10 was variable: Q10 increased with moisture in croplands but decreased in forests. The ESC captured significant parts of Q10 variability under dry (R2 = 0.44) and intermediate (R2 = 0.36) moisture conditions, where Q10 increased in the order cropland<grassland<forest. Overall, the estimated heterotrophic CO2 release from the catchment was up to 45% lower when ESC‐ and moisture‐specific Q10 values were used instead of 1.5, suggesting that scaling Q10 on the basis of both ESC and moisture might be a promising concept for spatially continuous assessments of carbon turnover at regional scales.

Global synthesis of temperature sensitivity of soil organic carbon decomposition: Latitudinal patterns and mechanisms

“…A clear picture presented that labile SOC is less sensitive to warming than recalcitrant SOC by using three methods (Figure ). Our findings were in line with the CQT hypothesis that recalcitrant SOC is more sensitive to warming than labile SOC, which was supported by some individual studies (e.g., Leifeld & Fuhrer, ; Conant et al, ; Craine et al, ; Lefèvre et al, ; Meyer et al, ). Although the kinetic theory underlying the CQT hypothesis (Davidson & Janssens, ), it is well applied only if SOC recalcitrance solely determines decomposition rates.…”

“…Furthermore, apparent increases in soil C availability at high temperature (Kadlec & Reddy, ) may intensify microbial nutrient limitation. In comparison with previous individual studies (Balogh et al, ; Meyer et al, ; Zheng et al, ), our work obtained a broad range of SOC concentration (0.5–551.6 g/kg), which may enable us to observe this threshold. Therefore, we can also assume that the various ranges of SOC contents in individual studies may cause the different correlations between Q 10 and SOC content.…”

“…Boxes show the 25% and 75% percentiles, and the black dots represent the mean of Q 10 value. Data below the box denote the sample number C r o p l a n d F o r e s t G r a s s l a n d T u n d r a P e a t l a n d W e t l a n d A n t a r c t i c among certain types of terrestrial ecosystems (Haddix et al, 2011;Meyer, Welp, & Amelung, 2018;Pang, Zhu, Lü, & Cheng, 2015).…”

Soil Respiration Components and their Temperature Sensitivity Under Chemical Fertilizer and Compost Application: The Role of Nitrogen Supply and Compost Substrate Quality

“…In the compost treatments, the lowest Q 10 value of Rh was present in BPFS. The Q 10 of Rh may not altered by the organic C quantity as observed here and by Meyer et al () but depend on C quality, with positive, negative, and nonsignificant relationships all being reported in the literature (Karhu et al, ). We found that the Q 10 of Rh increased with decreasing carbohydrates, proteins, and phenolic C, and increasing V/VSC (Figure ).…”

Litter Management as a Key Factor Relieves Soil Respiration Decay in an Urban-Adjacent Camphor Forest under a Short-Term Nitrogen Increment

“…where ST is the soil temperature, Rs is the soil respiration rate at the given soil temperature, and a and b are fitted parameters. Then, the temperature sensitivity (Q10) values were calculated by inserting the parameter b [37]:…”