Soil organic carbon under lockdown: Fresh plant litter as the nucleus for persistent carbon

Witzgall, Kristina; Vidal, Alix; Schubert, David; Höschen, Carmen; Schweizer, Steffen A.; Buegger, Franz; Pouteau, Valérie; Chenu, Claire; Mueller, Carsten W.

doi:10.21203/rs.3.rs-156043/v1

Cited by 4 publications

(4 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Plant-soil feedbacks include direct and indirect interactions between soils and plants affecting a myriad of ecosystem processes, including nutrient, water and carbon cycling, ecosystem productivity and erosion regulation (Figure 2). Plants are the main contributor of organic matter to the soil (Paul, 2016), where litter is decomposed by soil biota turning it into nutrients (which go back to plants, Throop & Archer, 2009) and into soil organic carbon (SOC; which affects soil properties and functioning Martínez-Fernández et al, 2021;Witzgall et al, 2021). Plants also regulate the effect of other abiotic factors on soils by protecting them from erosion (Schlesinger et al, 1990) and by regulating infiltration and run-off processes (Amenu & Kumar, 2008;D'Odorico et al, 2007;Laio et al, 2001).…”

Section: Mechanis Ms Link Ed To S O I L Disruption Pha Sementioning

confidence: 99%

Ecological mechanisms underlying aridity thresholds in global drylands

et al. 2021

View full text Add to dashboard Cite

1. With ongoing climate change, the probability of crossing environmental thresholds promoting abrupt changes in ecosystem structure and functioning is higher than ever. In drylands (areas where it rains <65% of what could be potentially evaporated), recent research has shown how the crossing of three aridity thresholds [at aridity (1-Aridity Index) values of 0.54, 0.70 and 0.80] leads to abrupt changes on ecosystem structural and functional attributes. Despite the importance of these findings and their implications to develop effective monitoring and adaptation actions to combat climate change and desertification, we lack a proper understanding of the mechanisms unleashing these abrupt shifts. 2. Here we review multiple mechanisms that may explain the existence of aridity thresholds observed across global drylands, and discuss the potential amplification mechanisms that may underpin hypothetical abrupt temporal shifts with climate change. 3. We propose that each aridity threshold is caused by different and specific mechanisms. The first threshold is mainly caused by physiological mechanisms of plant adaptation to water shortages. The second threshold is unleashed by different mechanisms involving soil processes and plant-soil interactions such as soil erosion, plant community shifts and nutrient cycling and circulation. The collapse of vegetation observed once the third aridity threshold (0.8) is crossed is caused by the mechanisms related to the survival limits of plants that may cause sudden cover and diversity losses and plant-atmospheric feedbacks that link vegetation collapse with further climate aridification.4. By identifying, revising and linking relevant mechanisms to each aridity threshold observed, we provide a set of specific hypotheses and identify knowledge gaps concerning the study of threshold emergence in drylands. We were also able to establish plausible factors that are context dependent and may influence the occurrence of abrupt ecosystem changes in time. Our review may help to focus future research efforts on aridity thresholds and to develop strategies to monitor, adapt to or even revert abrupt ecosystem changes across global drylands.

show abstract

Section: Mechanis Ms Link Ed To S O I L Disruption Pha Sementioning

confidence: 99%

Ecological mechanisms underlying aridity thresholds in global drylands

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Furthermore, SOC components can be classified from other perspectives, including chemical solvents, density, aggregates, and biological and physicochemical collaboration groups. The current research focuses on the differences in protection mechanisms, renewal rates, C source composition, C/N ratios, and their response mechanisms to climate change (Witzgall et al 2021, Sokol et al 2022a.…”

Section: Soc Content and Fractionsmentioning

confidence: 99%

“…Current modeling approaches consider temperature, soil water content, pH, particle size, and C and N interactions, which regulate SOC turnover time (Basile-Doelsch et al 2020). Combining mineral particles with various extents in soils controls theC pool decomposition rate (Witzgall et al 2021). Roots can stabilize SOC by forming soil aggregates, whereas mineral associations drive stabilization at depths greater than ∼30 cm (Jackson et al 2017).…”

Section: Soil Physical Propertiesmentioning

confidence: 99%

Research advances in mechanisms of climate change impacts on soil organic carbon dynamics

Guo,

Zeng,

Wang

et al. 2023

Environ. Res. Lett.

View full text Add to dashboard Cite

Soil, as the largest terrestrial carbon pool, has garnered significant attention concerning its response to global warming. However, accurately estimating the stocks and dynamics of soil organic carbon (SOC) remains challenging due to the complex and unclear influence mechanisms associated with biogeochemical processes in above- and belowground ecosystems, as well as technical limitations. Therefore, it is imperative to facilitate the integration of models and knowledge and promote dialogue between empiricists and modelers. This review provides a concise SOC turnover framework to understand the impact of climate change on SOC dynamics. It covers various factors such as warming, precipitation changes, elevated carbon dioxide, and nitrogen deposition. The review presents impact mechanisms from the perspective of organismal traits (plants, fauna, and microbes), their interactions, and abiotic regulation. Although valuable insights have been gained regarding SOC inputs, decomposition, and stabilization under climate change, there are still knowledge gaps that need to be addressed. In the future, it is essential to conduct systematic and refined research in this field. This includes standardizing the organismal traits most relevant to SOC, studying the standardization of SOC fractions and their resistance to decomposition, and focusing on the interactions and biochemical pathways of biological communities. Through further investigation of biotic and abiotic interactions, a clearer understanding can be attained regarding the physical protection, chemical stability, and biological driving mechanisms of SOC under climate change. This can be achieved by integrating multidisciplinary knowledge, utilizing novel technologies and methodologies, increasing in-situ experiments, and conducting long-term monitoring across multi-scales. By integrating reliable data and elucidating clear mechanisms, the accuracy of models can be enhanced, providing a scientific foundation for mitigating climate change.

show abstract

“…Here, we put forward a new line of evidence to estimate the contributions of plant and microbial residues to MAOM based on their stoichiometry. Plant residues are primarily incorporated into MAOM via the particulate organic matter (POM) pool (Coonan et al, 2020;Cotrufo & Lavallee, 2022;Witzgall et al, 2021), which consists largely of partially decomposed plant compounds (Guigue et al, 2021). Thus, the C/N ratio of POM can be used to estimate plant residue inputs to MAOM.…”

Section: Introductionmentioning

confidence: 99%

A stoichiometric approach to estimate sources of mineral‐associated soil organic matter

Chang,

Sokol,

van Groenigen

et al. 2023

Global Change Biology

View full text Add to dashboard Cite

Mineral‐associated soil organic matter (MAOM) is the largest, slowest cycling pool of carbon (C) in the terrestrial biosphere. MAOM is primarily derived from plant and microbial sources, yet the relative contributions of these two sources to MAOM remain unresolved. Resolving this issue is essential for managing and modeling soil carbon responses to environmental change. Microbial biomarkers, particularly amino sugars, are the primary method used to estimate microbial versus plant contributions to MAOM, despite systematic biases associated with these estimates. There is a clear need for independent lines of evidence to help determine the relative importance of plant versus microbial contributions to MAOM. Here, we synthesized 288 datasets of C/N ratios for MAOM, particulate organic matter (POM), and microbial biomass across the soils of forests, grasslands, and croplands. Microbial biomass is the source of microbial residues that form MAOM, whereas the POM pool is the direct precursor of plant residues that form MAOM. We then used a stoichiometric approach—based on two‐pool, isotope‐mixing models—to estimate the proportional contribution of plant residue (POM) versus microbial sources to the MAOM pool. Depending on the assumptions underlying our approach, microbial inputs accounted for between 34% and 47% of the MAOM pool, whereas plant residues contributed 53%–66%. Our results therefore challenge the existing hypothesis that microbial contributions are the dominant constituents of MAOM. We conclude that biogeochemical theory and models should account for multiple pathways of MAOM formation, and that multiple independent lines of evidence are required to resolve where and when plant versus microbial contributions are dominant in MAOM formation.

show abstract

Soil organic carbon under lockdown: Fresh plant litter as the nucleus for persistent carbon

Cited by 4 publications

References 34 publications

Ecological mechanisms underlying aridity thresholds in global drylands

Ecological mechanisms underlying aridity thresholds in global drylands

Research advances in mechanisms of climate change impacts on soil organic carbon dynamics

A stoichiometric approach to estimate sources of mineral‐associated soil organic matter

Contact Info

Product

Resources

About