Controls on microbially regulated soil organic carbon decomposition at the regional scale

Ali, Rana Shahbaz; Kandeler, Ellen; Marhan, Sven; Demyan, Michael Scott; Ingwersen, Joachim; Mirzaeitalarposhti, Reza; Rasche, Frank; Cadisch, Georg; Poll, Christian

doi:10.1016/j.soilbio.2017.12.007

Cited by 37 publications

(29 citation statements)

References 82 publications

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“…In our study, although some of collected several environmental and soil variables had statistical significant correlation with Q 10 values, the correlation coefficients of most relationships were relatively low, which maybe to some degree limits the implication of the findings in the study. The relative low coefficients perhaps indicated that some regulating factors of the spatial variation in Q 10 values were absent in this synthesis study such as microbial community composition (Ali et al, 2018;Thiessen et al, 2013; because most studies did not provide these data. In addition, we must be aware that a significant correlation does not imply the causality between two variables when interpreting the correlation coefficient.…”

Section: Q 10 In Different Ecosystems and Influencing Factorsmentioning

confidence: 93%

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

et al. 2019

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The response of soil organic carbon (SOC) decomposition to global warming is a potentially major source of uncertainty in climate prediction. However, the magnitude and direction of SOC cycle feedbacks under climate warming remain uncertain because of the knowledge gap about the global‐scale spatial pattern and temperature sensitivity (Q10) mechanism of SOC decomposition. Here, we collected data of Q10 and corresponding soil variables from 81 peer‐reviewed papers using laboratory incubation to explore how Q10 varied among different ecosystems at the global scale and whether labile and recalcitrant SOC pools had equal Q10 values. Q10 with a global average of 2.41 substantially varied among different ecosystems, ranging from the highest in cropland soils (2.76) and the lowest in wetland soils (1.84). Hump‐shaped correlations of Q10 values with the maximum at SOC = 190 g/kg and the minimum at clay = 37% were observed. However, the main influencing factors of Q10 differed among various ecosystems. Q10 values showed a clear decrease with increasing incubation temperature but no significant decrease above 25°C. In general, labile SOC was less sensitive than recalcitrant SOC to warming. Structural equation model analyses showed that total N and SOC accounted for 53% and 46%, respectively, of the variation in Q10 of labile SOC and recalcitrant SOC. This finding suggested that Q10 values of labile and recalcitrant SOC pools had different controlling factors. Our findings highlighted the importance of Q10’s variations in ecosystem types and the response of recalcitrant SOC to warming in predicting the soil C cycling and its feedback to climate change. Therefore, ecosystem type and difference in Q10 of labile and recalcitrant SOC should be considered to precisely predict the soil C dynamics under global warming. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13256/suppinfo is available for this article.

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Section: Q 10 In Different Ecosystems and Influencing Factorsmentioning

confidence: 93%

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

et al. 2019

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“…The respiratory coefficient represents the relation between carbon in the microbial biomass and total organic carbon (TOC). This coefficient indicates microbial biomass efficiency in using the available carbon for biosynthesis [21,22].…”

Section: Biological Indicatorsmentioning

confidence: 99%

Ecotoxicological Tests as a Tool to Assess the Quality of the Soil

Clasen¹,

Lisbôa²

2019

Soil Contamination and Alternatives for Sustainable Development

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Terrestrial ecotoxicology is used to evaluate the effects of substances that, whenever added to the soil, have impact on organisms and help measuring the responses from changes in the lethality, reproduction, development, and behavior of standardized soil organisms. Terrestrial ecotoxicology is a new tool that has been introduced in many countries, including Brazil, and yet little used. However, it is already widely used in Europe, besides being mandatory in research to indicate the toxicity of waste discharged in the soil. The aim of this chapter is to emphasize the importance and need of developing studies focused on the use of terrestrial ecotoxicology as a tool to assess fast and reliable responses from the toxicity of substances incorporated to the soil.

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“…With first-order turnover kinetics and a humification efficiency parameter (Fig. 1), the Daisy structure is similar to other widely used SOM models such as CENTURY (Parton et al, 1993) or ICBM (Andrén and Kätterer, 1997). Model SOM pool initialization using the DSI was compared to initialization via a steady-state assumption with different published turnover rates.…”

Section: Introductionmentioning

confidence: 99%

DRIFTS band areas as measured pool size proxy to reduce parameter uncertainty in soil organic matter models

et al. 2020

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Abstract. Soil organic matter (SOM) turnover models predict changes in SOM due to management and environmental factors. Their initialization remains challenging as partitioning of SOM into different hypothetical pools is intrinsically linked to model assumptions. Diffuse reflectance mid-infrared Fourier transform spectroscopy (DRIFTS) provides information on SOM quality and could yield a measurable pool-partitioning proxy for SOM. This study tested DRIFTS-derived SOM pool partitioning using the Daisy model. The DRIFTS stability index (DSI) of bulk soil samples was defined as the ratio of the area below the aliphatic absorption band (2930 cm−1) to the area below the aromatic–carboxylate absorption band (1620 cm−1). For pool partitioning, the DSI (2930 cm−1 ∕ 1620 cm−1) was set equal to the ratio of fast-cycling ∕ slow-cycling SOM. Performance was tested by simulating long-term bare fallow plots from the Bad Lauchstädt extreme farmyard manure experiment in Germany (Chernozem, 25 years), the Ultuna continuous soil organic matter field experiment in Sweden (Cambisol, 50 years), and 7 year duration bare fallow plots from the Kraichgau and Swabian Jura regions in southwest Germany (Luvisols). All experiments were at sites that were agricultural fields for centuries before fallow establishment, so classical theory would suggest that a steady state can be assumed for initializing SOM pools. Hence, steady-state and DSI initializations were compared, using two published parameter sets that differed in turnover rates and humification efficiency. Initialization using the DSI significantly reduced Daisy model error for total soil organic carbon and microbial carbon in cases where assuming a steady state had poor model performance. This was irrespective of the parameter set, but faster turnover performed better for all sites except for Bad Lauchstädt. These results suggest that soils, although under long-term agricultural use, were not necessarily at a steady state. In a next step, Bayesian-calibration-inferred best-fitting turnover rates for Daisy using the DSI were evaluated for each individual site or for all sites combined. Two approaches significantly reduced parameter uncertainty and equifinality in Bayesian calibrations: (1) adding physicochemical meaning with the DSI (for humification efficiency and slow SOM turnover) and (2) combining all sites (for all parameters). Individual-site-derived turnover rates were strongly site specific. The Bayesian calibration combining all sites suggested a potential for rapid SOM loss with 95 % credibility intervals for the slow SOM pools' half-life being 278 to 1095 years (highest probability density at 426 years). The credibility intervals of this study were consistent with several recently published Bayesian calibrations of similar two-pool SOM models, i.e., with turnover rates being faster than earlier model calibrations suggested; hence they likely underestimated potential SOM losses.

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Controls on microbially regulated soil organic carbon decomposition at the regional scale

Cited by 37 publications

References 82 publications

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

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

Ecotoxicological Tests as a Tool to Assess the Quality of the Soil

DRIFTS band areas as measured pool size proxy to reduce parameter uncertainty in soil organic matter models

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