Distinct bioenergetic signatures in particulate versus mineral-associated soil organic matter

Williams, Elizabeth K.; Fogel, Marilyn L.; Berhe, Asmeret Asefaw; Plante, Alain F.

doi:10.1016/j.geoderma.2018.05.024

Cited by 61 publications

(55 citation statements)

References 46 publications

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“…Low molecular weight compounds can become MAOM in two ways: they can leach from plant litter or be produced by exoenzyme depolymerization of plant litter and associate directly with the mineral phase (the “ex vivo modification pathway” sensu Liang, Schimel, & Jastrow, , and see Sanderman, Maddern, & Baldock, ), or they can be produced by the “in vivo microbial turnover pathway” sensu Liang et al () whereby microbiota decompose and transform organic material, resulting in necromass or exudates which are then incorporated into MAOM. Compared to POM, MAOM has a lower C/N ratio, fewer plant‐derived compounds, more microbial‐derived compounds, and a higher natural abundance δ 13 C (Baldock & Skjemstad, ; Christensen, ; Poirier et al, ; von Lützow et al, ; Williams, Fogel, Berhe, & Plante, ; Table ).…”

Section: Pom and Maom: Two Fundamentally Different Som Componentsmentioning

confidence: 99%

“…• More simple compounds with low activation energies • More assimilable compounds for microbes and plants Jilling et al (2018), Kleber et al (2015), Williams et al (2018) MAOM consists of single molecules or microscopic fragments of organic material that have either leached directly from plant material or been chemically transformed by the soil biota ( Figure 1). The defining difference between them is that MAOM is protected from decomposition through association with soil minerals, while POM is not.…”

Section: Dominant Chemical Constituentsmentioning

confidence: 99%

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Conceptualizing soil organic matter into particulate and mineral‐associated forms to address global change in the 21st century

Lavallee

Soong

Cotrufo

2019

Global Change Biology

1,060

598

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Managing soil organic matter (SOM) stocks to address global change challenges requires well‐substantiated knowledge of SOM behavior that can be clearly communicated between scientists, management practitioners, and policy makers. However, SOM is incredibly complex and requires separation into multiple components with contrasting behavior in order to study and predict its dynamics. Numerous diverse SOM separation schemes are currently used, making cross‐study comparisons difficult and hindering broad‐scale generalizations. Here, we recommend separating SOM into particulate (POM) and mineral‐associated (MAOM) forms, two SOM components that are fundamentally different in terms of their formation, persistence, and functioning. We provide evidence of their highly contrasting physical and chemical properties, mean residence times in soil, and responses to land use change, plant litter inputs, warming, CO2 enrichment, and N fertilization. Conceptualizing SOM into POM versus MAOM is a feasible, well‐supported, and useful framework that will allow scientists to move beyond studies of bulk SOM, but also use a consistent separation scheme across studies. Ultimately, we propose the POM versus MAOM framework as the best way forward to understand and predict broad‐scale SOM dynamics in the context of global change challenges and provide necessary recommendations to managers and policy makers.

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Section: Pom and Maom: Two Fundamentally Different Som Componentsmentioning

confidence: 99%

Section: Dominant Chemical Constituentsmentioning

confidence: 99%

Conceptualizing soil organic matter into particulate and mineral‐associated forms to address global change in the 21st century

Lavallee

Soong

Cotrufo

2019

Global Change Biology

1,060

598

View full text Add to dashboard Cite

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“…Particle size, distribution, and mineral-metal composition can provide complementary information regarding transport velocities, weathering, and hydrologic conditions (e.g., exposure to fluctuating redox conditions). In addition to fingerprint methods, direct measurements OM age, through radiocarbon measurements (Marwick et al, 2015) or metabolic availability indicated by O/C content versus H/C content (Kim et al, 2003;Williams et al, 2018) can be achieved. When the OM chemical composition and matrix properties are used in combination then a composite picture is assembled similar to the turnover frequency histograms depicted in Figures 1, 2.…”

Section: Substrate Levelmentioning

confidence: 99%

Integrating Aquatic and Terrestrial Perspectives to Improve Insights Into Organic Matter Cycling at the Landscape Scale

et al. 2019

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Kayler et al. Landscape Organic Matter Turnover of abiotic conditions, substrate quality, and microbial community dynamics. We highlight the disproportionate impact anthropogenic activities can have on OM cycling across the landscape. This includes reversing natural OM flows through the landscape, disrupting ecosystem connectivity, and nutrient additions that cascade across the landscape. This knowledge is crucial for a better understanding of OM cycling in a landscape context, in particular since terrestrial and aquatic compartments may respond differently to the ongoing changes in climate, land use, and other anthropogenic interferences.

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“…Energy density (ED, in J mg −1 OM) was thus determined by dividing energy content by TG mass loss (Plante et al 2011;Rovira et al 2008). Activation energy (E a , in kJ mol −1 CO 2 ) was determined following the methods of Williams et al (2014), assuming first-order reaction kinetics during ramped combustion, and described in further detail in Williams et al (2018). The return-onenergy-investment (ROI) ratio (Harvey et al 2016) which has been demonstrated to be directly related to the biodegradability of pyrogenic organic matter was calculated for each biochar sample by dividing ED by E a .…”

Section: Elemental and Thermal Analysesmentioning

confidence: 99%

Effects of 7 years of field weathering on biochar recalcitrance and solubility

Williams

Jones

Sanders

et al. 2019

Biochar

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How weathering affects the physiochemical properties of biochar and its long-term carbon (C) sequestration potential remains unclear. In this study, we measured changes in biochar recalcitrance and solubility after 7 years of weathering in a cultivated field. Biochar recalcitrance and biodegradability of weathered and unweathered hardwood biochar mixtures were determined by thermal analysis (differential scanning calorimetry) and evolved gas analysis. Differences in biochar solubility and the chemical composition of biochar-derived dissolved organic carbon (DOC) were determined by repeated laboratory leaching and UV-Vis spectroscopy. The surface carbon-oxidation state (C ox) of biochar increased by 117.6-158.2% with weathering in the field, and there was an average of 0.9-1.2% decrease in biochar C contents per year. However, thermal indices of biochar recalcitrance and biodegradability, which suggested intermediate C sequestration potential, were not significantly different between weathered and unweathered biochars. The O:C ratio increased with weathering suggesting an increase in biodegradability, however, both weathered and unweathered biochars were still estimated to have half-lives of over 1000 years. Water-soluble organic carbon (WSOC) concentrations from the unweathered biochar rapidly decreased during laboratory leaching to levels similar to the field-weathered biochars, and aromaticity (SUVA 254) of WSOC increased from 5.9% in the unweathered biochar to 42% aromaticity in the biochars weathered for 7 years. We conclude that during short-term (years) weathering under field conditions, there is continued solubilization of increasingly aromatic biochar-C compounds, however, this accounts for a relatively small proportion of biochar C such that there is little-to-no change in biochar stability or C sequestration potential after field application.

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Distinct bioenergetic signatures in particulate versus mineral-associated soil organic matter

Cited by 61 publications

References 46 publications

Conceptualizing soil organic matter into particulate and mineral‐associated forms to address global change in the 21st century

Conceptualizing soil organic matter into particulate and mineral‐associated forms to address global change in the 21st century

Integrating Aquatic and Terrestrial Perspectives to Improve Insights Into Organic Matter Cycling at the Landscape Scale

Effects of 7 years of field weathering on biochar recalcitrance and solubility

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