Stable isotopes reveal that fungal residues contribute more to mineral-associated organic matter pools than plant residues

Klink, Saskia; Keller, Adrienne B.; Wild, Andreas J.; Baumert, Vera; Gube, Matthias; Lehndorff, Eva; Meyer, Nele; Mueller, Carsten W.; Phillips, Richard P.; Pausch, Johanna

doi:10.1016/j.soilbio.2022.108634

Cited by 50 publications

(35 citation statements)

References 73 publications

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“…Rhizodeposition has the highest MAOC formation efficiency and root biomass input has the highest POC formation efficiency (Villarino et al, 2021 ). This finding is confirmed by a recent study revealing that residues from saprotrophic and mycorrhizal fungi contribute more to MAOC than plant residues (Klink et al, 2022 ). Despite the “priming effect” of root exudates (increased microbial activity leading to destabilization of already existing C pools), Panchal et al ( 2022 ) suggest that the rhizosphere environment of forests can help to stabilize root exudates due to the accumulation of microbial biomass residues, leading to long‐term sequestration.…”

supporting

confidence: 78%

Closing in on the last frontier: C allocation in the rhizosphere

Obersteiner

Klein

2022

Global Change Biology

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Increased belowground C allocation of trees, especially enhanced rhizodeposition, might lead to long‐term C sequestration in forest soil. Microbes are crucial players in this complex process of forming stable soil organic carbon (SOC). Hence, research must be accelerated to understand the complex rhizosphere processes and their effect on stable SOC formation. This is a commentary on Hikino et al., 2022, https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16388

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supporting

confidence: 78%

Closing in on the last frontier: C allocation in the rhizosphere

Obersteiner

Klein

2022

Global Change Biology

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“…Soil peptides/proteins, through turnover by microorganisms (18) and preservation in soil (14,15), are a major form of both bioavailable and sequestered OM. Once formed, these microbial-derived OMs will become more stable by binding further to minerals (65) or tannins (21,22). Some other biotic and abiotic factors, including reactive nitrogen deposition (66), past legacies of activity, and extreme events (10), need to be included for consideration in subsequent studies to quantify their relative importance determining the role proteinaceous amino acids play in soil OM formation.…”

Section: Direct and Indirect Drivers Of The Accrual Of Amino Acidsmentioning

confidence: 99%

Precipitation-derived effects on the characteristics of proteinaceous soil organic matter across the continental United States

Hong

Ma²,

Smith³

et al. 2022

Front. Soil Sci.

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Proteinaceous amino acids composed up to 50% of microbial biomass, are a primary building block of soil organic nitrogen, and play a key role in soil organic N and C cycling. However, the large-scale drivers on these organic nitrogen pools is less explored. We hypothesized that the trends related to vegetation, soil mineralogy and climate will change the composition of hydrolyzable amino acids (HAAs), both within and between each horizon. Herein we report on the patterns of HAAs, and their dependence on soil (e.g., Al, Fe, pH) and climate (e.g., precipitation) factors between soil horizons across the continental U.S. It was found that the effect of vegetation type on HAAs was greater in the A horizon than in the C horizon, which was related to the different stages of the vegetation-associated decomposition and pedogenesis processes. A similar Leu-Phe-Ile-Gly co-occurrence structure was found in both soil horizons suggesting some similarity in processes that enrich organics in soil. Precipitation, but not temperature, showed significant associations with HAA composition. The chemical properties of the soil, including pH and mineral metals (Fe, Mn, Al, Ca), also influenced the HAAs’ characteristics. In particular, some specific HAAs (Glx, Asn, and Ala) mainly reflected the HAAs’ response to the environmental gradients in both horizons. The effect of precipitation on HAAs exhibits as a complex relationship mediated through organic matter, pH and minerals. To our knowledge, this is the first study to assess continental-wide descriptors of the largest soil organic N pool, showing that pH, Fe, Ca, precipitation and vegetation explain soil AA composition. The role played by each of these drivers in the accrual and turnover of organic matter over large regional scales deserve further scrutiny. The large surface and subsurface HAA data set from this study should help change the way micro-scale conceptual and mechanistic models describe the chemical interactions and source pools that drive soil organic nitrogen, and possibly soil organic matter composition over regional scales.

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“…1). In low-salinity soil, microbial necromass accumulated at the same rate as SOC indicated that microbial anabolism had a synergistic effect with SOC accumulation (Liang et al, 2019;Klink et al, 2022). However, the decrease in the ratio of amino sugars to SOC suggested that the relative contribution of microbial anabolism to SOC accumulation decreased in mediumsalinity soil.…”

Section: Resultsmentioning

confidence: 99%

“…Lett., 2023, 5(4): 220168 decomposed plant debris is typically considered to be predominant regarding the formation of particulate organic C (POC) and directly contributes to SOC accumulation (Witzgall et al, 2021;. However, increasing evidence suggests that microbial anabolism may contribute more to SOC storage in the form of microbial necromass (Liang et al, 2017;Klink et al, 2022). Recently, accumulation of fungal and bacterial necromasses in salt-affected soils was found to depend on salinity (Chen et al, 2021;Shao et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Straw-returning reduces the contribution of microbial anabolism to salt-affected soil organic carbon accumulation over a salinity gradient

Huo

et al. 2023

Soil Ecol. Lett.

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In low-salinity soil, straw-returning did not change necromass contribution to SOC.• In medium-salinity soil, straw-returning reduced necromass contribution to SOC.• Straw-returning reduced POC contribution to SOC in lowsalinity soil.• Straw-returning increased POC contribution to SOC in medium-salinity soil.• Salinity affects the contribution of microbial-derived and plant-derived C to SOC. Salinization affects microbial-mediated soil organic carbon (SOC) dynamics. However, the mechanisms of SOC accumulation under agricultural management practices in saltaffected soils remain unclear. We investigated the relative contribution of microbial-derived and plant-derived C to SOC accumulation in coastal salt-affected soils under strawreturning, by determining microbial necromass biomarkers (amino sugars) and particulate organic C (POC). Results showed that, straw-returning increased necromass accumulation in low-salinity soil but did not change its contribution to SOC. In medium-salinity soil, straw-returning did not increase necromass accumulation but decreased its contribution to SOC. In low-and medium-salinity soils, the contribution of POC to SOC showed the opposite direction to that of the necromass. These results suggest that under straw-returning, the relative contribution of microbial-derived C to SOC decreased with increasing salinity, whereas the reverse was true for plant-derived C. Our results highlighted that straw-returning reduces the contribution of microbial anabolism to SOC accumulation in salt-affected soils with increasing salinity.

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Stable isotopes reveal that fungal residues contribute more to mineral-associated organic matter pools than plant residues

Cited by 50 publications

References 73 publications

Closing in on the last frontier: C allocation in the rhizosphere

Closing in on the last frontier: C allocation in the rhizosphere

Precipitation-derived effects on the characteristics of proteinaceous soil organic matter across the continental United States

Straw-returning reduces the contribution of microbial anabolism to salt-affected soil organic carbon accumulation over a salinity gradient

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