Soil properties control decomposition of soil organic carbon: Results from data-assimilation analysis

Xu, Xingkai; Shi, Zheng; Li, Dejun; Rey, Ana; Ruan, Honghua; Craine, Joseph M.; Liang, Junyi; Zhou, Jizhong; Luo, Yiqi

doi:10.1016/j.geoderma.2015.08.038

Cited by 176 publications

(98 citation statements)

References 49 publications

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“…5d), consistent with previous expectations (Schimel et al, 1994;Xu et al, 2016). In sites where clay content is < 50%…”

supporting

confidence: 92%

Stable isotopic constraints on global soil organic carbon turnover

Chao¹,

Houlton²,

Li³

et al. 2017

Preprint

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Abstract. Carbon dioxide release during soil organic carbon (SOC) turnover is a pivotal component of atmospheric CO2concentrations and global climate change. However, reliably measuring SOC turnover rates at large spatial and temporal scales 10 remains challenging. Here we use a natural carbon isotope approach, defined as beta (β), which was quantified from the δ 13 C of vegetation and soil reported in the literature (182 separate soil profiles), to examine large-scale controls of climate, soil physical properties and nutrients over patterns of SOC turnover across terrestrial biomes worldwide. We report a significant relationship between β and calculated soil C turnover rates (k), which were estimated by dividing soil heterotrophic respiration by SOC pools. ln(-β) exhibits a significant linear relationship with mean annual temperature, but a more complex polynomial relationship with 15 mean annual precipitation, implying strong-feedbacks of SOC turnover to climate changes. Soil nitrogen (N) and clay content correlate strongly and positively with ln(-β), revealing the additional influence of nutrients and physical soil properties on SOC decomposition rates. Furthermore, a strong (R 2 = 0.85; p<0.001) linear relationship between ln(-β) and estimates of litter and root decomposition rates suggests similar controls over rates of organic matter decay among the generalized soil C stocks. Overall, these findings demonstrate the utility of soil δ 13 C for independently benchmarking global models of soil C turnover and thereby 20improving predictions of multiple global change influences over terrestrial C-climate feedback.

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“…5d), consistent with previous expectations (Schimel et al, 1994;Xu et al, 2016). In sites where clay content is < 50%…”

supporting

confidence: 92%

Stable isotopic constraints on global soil organic carbon turnover

Chao¹,

Houlton²,

Li³

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…Those soil types have, on average, a clay content of about 30 and 45%, respectively, which may help to slowdown SOC decomposition compared to coarser soils [58,59]. This is related to the fact that clay particles can help to stabilise decomposing litter by mineral associated bonds [1,2] and the aggregation is stronger, also promoting physical inaccessibility of SOC to the microbial community [3].…”

Section: Reasons For Heterogeneitymentioning

confidence: 99%

“…However, site latitude was positively correlated to differences in full profile C stocks. Whether this is dependent on a lower decomposition rate at higher latitudes due to lower temperatures could be possible but the rates are also determined by interactions of a number of physical and chemical factors influencing the microbial enzymatic activities in soils [59].…”

Section: Reasons For Heterogeneitymentioning

confidence: 99%

How does tillage intensity affect soil organic carbon? A systematic review

et al. 2017

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Background: The loss of carbon (C) from agricultural soils has been, in part, attributed to tillage, a common practice providing a number of benefits to farmers. The promotion of less intensive tillage practices and no tillage (NT) (the absence of mechanical soil disturbance) aims to mitigate negative impacts on soil quality and to preserve soil organic carbon (SOC). Several reviews and meta-analyses have shown both beneficial and null effects on SOC due to no tillage relative to conventional tillage, hence there is a need for a comprehensive systematic review to answer the question: what is the impact of reduced tillage intensity on SOC? Methods:We systematically reviewed relevant research in boreo-temperate regions using, as a basis, evidence identified within a recently completed systematic map on the impacts of farming on SOC. We performed an update of the original searches to include studies published since the map search. We screened all evidence for relevance according to predetermined inclusion criteria. Studies were appraised and subject to data extraction. Meta-analyses were performed to investigate the impact of reducing tillage [from high (HT) to intermediate intensity (IT), HT to NT, and from IT to NT] for SOC concentration and SOC stock in the upper soil and at lower depths.Results: A total of 351 studies were included in the systematic review: 18% from an update of research published in the 2 years since the systematic map. SOC concentration was significantly higher in NT relative to both IT [1.18 g/ kg ± 0.34 (SE)] and HT [2.09 g/kg ± 0.34 (SE)] in the upper soil layer (0-15 cm). IT was also found to be significant higher [1.30 g/kg ± 0.22 (SE)] in SOC concentration than HT for the upper soil layer (0-15 cm). At lower depths, only IT SOC compared with HT at 15-30 cm showed a significant difference; being 0.89 g/kg [± 0.20 (SE)] lower in intermediate intensity tillage. For stock data NT had significantly higher SOC stocks down to 30 cm than either HT [4.61 Mg/ ha ± 1.95 (SE)] or IT [3.85 Mg/ha ± 1.64 (SE)]. No other comparisons were significant. Conclusions:The transition of tilled croplands to NT and conservation tillage has been credited with substantial potential to mitigate climate change via C storage. Based on our results, C stock increase under NT compared to HT was in the upper soil (0-30 cm) around 4.6 Mg/ha (0.78-8.43 Mg/ha, 95% CI) over ≥ 10 years, while no effect was detected in the full soil profile. The results support those from several previous studies and reviews that NT and IT increase SOC in the topsoil. Higher SOC stocks or concentrations in the upper soil not only promote a more productive soil with higher biological activity but also provide resilience to extreme weather conditions. The effect of tillage practices on total SOC stocks will be further evaluated in a forthcoming project accounting for soil bulk densities and crop yields. Our findings can hopefully be used to guide policies for sustainable management of agricultural soils.

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“…This assumption is built upon observations from litter and SOC decomposition. Analysis of data from nearly 300 studies of litter decomposition (Zhang et al, 2008), about 500 studies of soil incubation (Schädel et al, 2014;Xu et al, 2016), more than 100 studies of forest succession (Yang et al, 2011), and restoration (Matamala et al, 2008) almost all suggests that the first-order decay function captures macroscopic patterns of land C dynamics. Even so, its biological, chemical, and physical underpinnings need more study .…”

Section: Assumptions Of the C Cycle Models And Validity Of This Analysismentioning

confidence: 99%

Transient dynamics of terrestrial carbon storage: mathematical foundation and its applications

et al. 2017

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Abstract. Terrestrial ecosystems have absorbed roughly 30 % of anthropogenic CO 2 emissions over the past decades, but it is unclear whether this carbon (C) sink will endure into the future. Despite extensive modeling and experimental and observational studies, what fundamentally determines transient dynamics of terrestrial C storage under global change is still not very clear. Here we develop a new framework for understanding transient dynamics of terrestrial C storage through mathematical analysis and numerical experiments. Our analysis indicates that the ultimate force driving ecosystem C storage change is the C storage capacity, which is jointly determined by ecosystem C input (e.g., net primary production, NPP) and residence time. Since both C input and residence time vary with time, the C storage capacity is timedependent and acts as a moving attractor that actual C storage chases. The rate of change in C storage is proportional to the C storage potential, which is the difference between the current storage and the storage capacity. The C storage capacity represents instantaneous responses of the land C cycle to external forcing, whereas the C storage potential represents the internal capability of the land C cycle to influence the C change trajectory in the next time step. The influence happens through redistribution of net C pool changes in a network of pools with different residence times.Moreover, this and our other studies have demonstrated that one matrix equation can replicate simulations of most land C cycle models (i.e., physical emulators). As a result, simulation outputs of those models can be placed into a threedimensional (3-D) parameter space to measure their differences. The latter can be decomposed into traceable components to track the origins of model uncertainty. In addition, the physical emulators make data assimilation computationPublished by Copernicus Publications on behalf of the European Geosciences Union. 146Y. Luo et al.: Land carbon storage dynamics ally feasible so that both C flux-and pool-related datasets can be used to better constrain model predictions of land C sequestration. Overall, this new mathematical framework offers new approaches to understanding, evaluating, diagnosing, and improving land C cycle models.

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Soil properties control decomposition of soil organic carbon: Results from data-assimilation analysis

Cited by 176 publications

References 49 publications

Stable isotopic constraints on global soil organic carbon turnover

Stable isotopic constraints on global soil organic carbon turnover

How does tillage intensity affect soil organic carbon? A systematic review

Transient dynamics of terrestrial carbon storage: mathematical foundation and its applications

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