Isolating organic carbon fractions with varying turnover rates in temperate agricultural soils – A comprehensive method comparison

Poeplau, Christopher; Don, Axel; Six, Johan; Kaiser, Michael; Benbi, D. K.; Chenu, Claire; Cotrufo, M. Francesca; Derrien, Delphine; Gioacchini, Paola; Grand, Stéphanie; Gregorich, E.G.; Griepentrog, Marco; Gunina, Anna; Haddix, Michelle L.; Kuzyakov, Yakov; Kühnel, Anna; Macdonald, Lynne M.; Soong, Jennifer L.; Trigalet, Sylvain; Vermeire, Marie-Liesse; Rovira, Pere; Wesemael, Bas van; Wiesmeier, Martin; Yeasmin, Sabina; Yevdokimov, I. V.; Nieder, Rolf

doi:10.1016/j.soilbio.2018.06.025

Cited by 311 publications

(205 citation statements)

References 99 publications

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“…While POM and MAOM have been shown time and again to have highly contrasting behavior in response to cultivation (Cambardella & Elliott, ; Collins et al, ; Duval et al, ), this concept was deemphasized as attention grew around physical protection in aggregates, and the roles of different aggregate size classes as SOM diagnostic features (Plaza‐Bonilla, Álvaro‐Fuentes, & Cantero‐Martínez, ; Six et al, ). The prominence of POM and MAOM as the two physical soil fractions with the largest differences in response to cultivation and mean residence times (MRTs) was recently reiterated in a comprehensive SOM fractionation methods comparison by Poeplau et al ().…”

Section: Contrasting Responses Of Pom and Maom To Global Change Factorsmentioning

confidence: 99%

“…The reality of soil separation procedures is that they necessitate operational definitions of soil components, including POM and MAOM. Both POM and MAOM go by many different names throughout the literature (e.g., “light fraction” for light POM) and are operationally defined in various ways (Christensen, ; Curtin, Beare, Qiu, & Sharp, ; Elliott & Cambardella, ; Marzaioli et al, ; Poeplau et al, ; von Lützow et al, ). By definition, MAOM is associated with silt and clay minerals, and these are operationally defined as smaller than 20–63 µm (the upper size limit specification varies by region; Totsche et al, ).…”

Section: Operational Definitions Of Pom and Maommentioning

confidence: 99%

“…All SOM has the potential to be subject to spatial constraints; MAOM is protected by mineral association, and both POM and MAOM can be occluded within large aggregates (Table ). Occlusion in large aggregates slows decomposition, but to a lesser degree than mineral association (Kögel‐Knabner et al, ; Poeplau et al, ; Puget, Chenu, & Balesdent, ; Schrumpf et al, ). Given this, the persistence of POM is controlled mainly by microbial and enzymatic inhibition (plus some short‐term occlusion in aggregates), while that of MAOM is controlled mainly by mineral association.…”

Section: Contrasting Responses Of Pom and Maom To Global Change Factorsmentioning

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

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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: Contrasting Responses Of Pom and Maom To Global Change Factorsmentioning

confidence: 99%

Section: Operational Definitions Of Pom and Maommentioning

confidence: 99%

Section: Contrasting Responses Of Pom and Maom To Global Change Factorsmentioning

confidence: 99%

See 1 more Smart Citation

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

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796

598

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“…LF, heavy POM and MAOM can be considered primary SOM fractions that may be found in soil free or occluded in aggregates of different size classes (Christensen, 2001). Aggregates are composite dynamic structures (Jastrow, 1996;Poeplau et al, 2018;Six, Elliott, & Biochemistry, 2000). Micro-aggregates (250-53 μm) have been consistently found to resist disturbance, thus are believed to offer protection from further mineralization to the occluded primary SOM fractions (Six & Paustian, 2014).…”

Section: Introductionmentioning

confidence: 99%

Pathways of soil organic matter formation from above and belowground inputs in a Sorghum bicolor bioenergy crop

Fulton-Smith

Cotrufo

2019

GCB Bioenergy

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When aboveground materials are harvested for fuel production, such as with Sorghum bicolor, the sustainability of annual bioenergy feedstocks is influenced by the ability of root inputs to contribute to the formation and persistence of soil organic matter (SOM), and to soil fertility through nutrient recycling. Using 13C and 15N labeling, we traced sorghum root and leaf litter‐derived C and N for 19 months in the field as they were mineralized or formed SOM. Our in situ litter incubation experiment confirms that sorghum roots and leaves significantly differ in their inherent chemical recalcitrance. This resulted in different contributions to C and N storage and recycling. Overall root residues had higher biochemical recalcitrance which led to more C retention in soil (27%) than leaf residues (19%). However, sorghum root residues resulted in higher particulate organic matter (POM) and lower mineral associated organic matter (MAOM), deemed to be the most persistent fraction in soil, than leaf residues. Additionally, the overall higher root‐derived C retention in soil led to higher N retention, reducing the immediate recycling of fertility from root as compared to leaf decomposition. Our study, conducted in a highly aggregated clay‐loam soil, emphasized the important role of aggregates in new SOM formation, particularly the efficient formation of MAOM in microaggregate structures occluded within macroaggregates. Given the known role of roots in promoting aggregation, efficient formation of MAOM within aggregates can be a major mechanism to increase persistent SOM storage belowground when aboveground residues are removed. We conclude that promoting root inputs in S. bicolor bioenergy production systems through plant breeding efforts may be an effective means to counterbalance the aboveground residue removal. However, management strategies need to consider the quantity of inputs involved and may need to support SOM storage and fertility with additional organic matter additions.

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“…There are many different approaches (chemical, physical and / or biochemical) that can be used to specify fractions in a bulk soil sample 18,19 . Simple density fractionation is a physical separation which has been widely used by soil scientists to study SOM dynamics (see for instance Grunwald et al, 2017 and references therein)…”

Section: Introductionmentioning

confidence: 99%

Combined Size and Density Fractionation of Soils for Investigations of Organo-Mineral Interactions

Viret

Grand

2019

JoVE

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Combined size and density fractionation (CSDF) is a method used to physically separate soil into fractions differing in particle size and mineralogy. CSDF relies on sequential density separation and sedimentation steps to isolate (1) the free light fraction (uncomplexed organic matter), (2) the occluded light fraction (uncomplexed organic matter trapped in soil aggregates) and (3) a variable number of heavy fractions (soil minerals and their associated organic matter) differing in composition. Provided that the parameters of the CSDF (dispersion energy, density cut-offs, sedimentation time) are properly selected, the method yields heavy fractions of relatively homogeneous mineral composition. Each of these fractions is expected to have a different complexing ability towards organic matter, rendering this a useful method to isolate and study the nature of organo-mineral interactions. Combining density and particle size separation brings an improved resolution compared to simple size or density fractionation methods, allowing the separation of heavy components according to both mineralogy and size (related to surface area) criteria. As is the case for all physical fractionation methods, it may be considered as less disruptive or aggressive than chemically-based extraction methods. However, CSDF is a time-consuming method and furthermore, the quantity of material obtained in some fractions can be limiting for subsequent analysis. Following CSDF, the fractions may be analyzed for mineralogical composition, soil organic carbon concentration and organic matter chemistry. The method provides quantitative information about organic carbon distribution within a soil sample and brings light to the sorptive capacity of the different, naturally-occurring mineral phases, thus providing mechanistic information about the preferential nature of organo-mineral interactions in soils (i.e., which minerals, what type of organic matter).

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Isolating organic carbon fractions with varying turnover rates in temperate agricultural soils – A comprehensive method comparison

Cited by 311 publications

References 99 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

Pathways of soil organic matter formation from above and belowground inputs in a Sorghum bicolor bioenergy crop

Combined Size and Density Fractionation of Soils for Investigations of Organo-Mineral Interactions

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