Soil organic matter is stabilized by organo-mineral associations through two key processes: The role of the carbon to nitrogen ratio

Kopittke, Peter M.; Dalal, Ram C.; Hoeschen, Carmen; Cui, Ling; Menzies, Neal W.; Mueller, Carsten W.

doi:10.1016/j.geoderma.2019.113974

Cited by 137 publications

(79 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…respiration increased rapidly at the early stage of incubation (0-15 DAI), decreased rapidly during mid incubation (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and then decreased relatively slightly during the later stage of incubation (31)(32)(33)(34)(35)(36)(37)(38)(39)(40). These changes in SR suggested that labile organic matter may have depleted quickly along with incubation time as observed in previous studies [6].…”

Section: Plos Onesupporting

confidence: 59%

See 1 more Smart Citation

Increasing temperature can modify the effect of straw mulching on soil C fractions, soil respiration, and microbial community composition

Wang

Xie

et al. 2020

PLoS ONE

View full text Add to dashboard Cite

Straw mulching has been widely adopted in dryland cropping but its effect on soil respiration and microbial communities under warming are not well understood. Soil samples were collected from a corn field with straw mulching (SM) for nine years and without straw mulching (CK), and incubated at 15˚C, 25˚C, and 35˚C for 60 days. Soil respiration, C fractions and bacterial and fungal community structure were measured SM had greater soil organic carbon and potential C mineralization and a similar microbial biomass carbon throughout the incubation when compared with CK. Soil respiration increased with increasing temperature and its temperature sensitivity (Q 10) was lower with SM than CK. Similar microbial community composition was found in the soils with SM and CK before incubation. However, SM had a greater bacterial richness and the relative abundances of Proteobacteria, Acidobacteria, Nitrospirae, Planctomycetes, Bacteroidetes, and Basidiomycota, but lower relative abundances of Actinobacteria, Chloroflexi, and Ascomycota than CK after incubation. Bacterial richness and diversity were greater at 15˚C and 25˚C than 35˚C, but there was no difference in fungal richness and diversity among the incubation temperatures. As temperature increased, the relative abundances of Chloroflexi, Acidobacteria, and Bacteroidetes decreased, but Gemmatimonadetes and Ascomycota increased, and were significantly correlated with soil C fractions and respiration. These findings indicated that the effect of straw mulching on soil C cycling and microbial community structure can be highly modified by increasing temperature.

show abstract

Section: Plos Onesupporting

confidence: 59%

“…However, Józefowska et al [35] found a negative correlation between C content and respiration, which may be related to the protection of soil organic matter. Soil organic matter may be stabilized in the form of organo-mineral complexes [36], which are resistant to microbial degradation.…”

Section: Plos Onementioning

confidence: 99%

Increasing temperature can modify the effect of straw mulching on soil C fractions, soil respiration, and microbial community composition

Wang

Xie

et al. 2020

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Both fractions also showed distinct peaks around 170 to 175 ppm, representing partly esterified carboxyl groups and amide C that stems predominantly from proteins (Koelbl and Koegel-Knabner, 2004). The clay-sized MAOM 370 showed distinctly higher amounts of protein C (Table 3) compared to all POM fractions, which corroborates the preferential association of N-rich microbial residues at mineral surfaces (Kleber et al, 2007;Kopittke et al, 2018Kopittke et al, , 2020. This highlights the fact that the association of OM with mineral surfaces presumably follows the same mechanisms as previously described for temperate soils (Kleber et al, 2007).…”

Section: Molecular and Isotopic Analyses Confirm The Differences In Tmentioning

confidence: 65%

From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils

Prater¹,

Zubrzycki²,

Buegger³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Permafrost-affected soils of the Arctic account for 70 % or 727 Pg of the soil organic carbon (C) stored in the permafrost region and therefore play a major role in the global C cycle. Most studies on the budgeting of C storage and the quality of soil organic matter (SOM) in the northern circumpolar region focus on bulk soils. Thus, although there is a plethora of assumptions regarding differences in terms of C turnover or stability, only little knowledge is available on the mechanisms stabilizing organic C in Arctic soils besides impaired decomposition due to low temperatures. To gain such knowledge, we investigated soils from Samoylov Island in the Lena River Delta with respect to the composition and distribution of organic C among differently stabilized SOM fractions. The soils were fractionated according to density and particle size to obtain differently stabilized SOM fractions differing in chemical composition and thus bioavailability. To better understand the chemical alterations from plant-derived organic particles in these soils rich in fibrous plant residues to mineral-associated SOM, we analysed the elemental, isotopic and chemical composition of particulate OM (POM) and clay-sized mineral-associated OM (MAOM). We demonstrate that the SOM fractions that contribute with about 17 kg C m−3 for more than 60 % of the C stock are highly bioaccessible and that most of this labile C can be assumed to be prone to mineralization under warming conditions. Thus, the amount of relatively stable, small occluded POM and clay-sized MAOM that account currently with about 10 kg C m−3 for about 40 % of the C stock will most probably be crucial for the quantity of C protected from mineralization in these Arctic soils in a warmer future. Using δ15N as proxy for nitrogen (N) balances indicated an important role of N inputs by biological N fixation, while gaseous N losses appeared less important. However, this could change, as with about 0.4 kg N m−3 one third of the N is present in bioaccessible SOM fractions, which could lead to increases in mineral N cycling and associated N losses under global warming. Our results highlight the vulnerability of SOM in Arctic permafrost-affected soils under rising temperatures, potentially leading to unparalleled greenhouse gas emissions from these soils.

show abstract

“…The C/N ratios notably differed both between the single depth layers and the overall soil cores. The variable bulk soil C/N ratios with depth can be assigned to the translocation of fresh plant-derived OM from top-to subsoils by cryoturbation, leading to specific soil layers which also can contain so-called cryoturbated pockets rich in rather less decomposed OM with higher C/N ratios (Kaiser et al, 2007;Krüger et al, 2014). Such an incorporation of OM in the subsoil is also confirmed by the high amounts of POM present in these depth increments dominated by rather fibrous plant residues.…”

Section: Cryoturbation Determines Bulk Soil Organic Matter Distributionmentioning

confidence: 83%

“…showed wider C/N ratios indicative of the dominance of plant-derived OM, while the fourth core had lower C/N ratios, pointing to a larger amount of microbial-derived OM. Generally, C/N ratios decrease with ongoing decomposition (Kramer et al, 2003), as the proportion of microbial-derived OM with its characteristically low C/N ratio increases after the depolymerization of plant-derived organic macromolecules. This goes along with the increased binding of microbial residues to mineral particle surfaces and thus OM becoming less bioavailable (Connin et al, 2001;Vitousek et al, 2002).…”

Section: Cryoturbation Determines Bulk Soil Organic Matter Distributionmentioning

confidence: 99%

From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils

et al. 2020

Self Cite

View full text Add to dashboard Cite

Abstract. Permafrost-affected soils of the Arctic account for 70 % or 727 Pg of the soil organic carbon (C) stored in the northern circumpolar permafrost region and therefore play a major role in the global C cycle. Most studies on the budgeting of C storage and the quality of soil organic matter (OM; SOM) in the northern circumpolar region focus on bulk soils. Thus, although there is a plethora of assumptions regarding differences in terms of C turnover or stability, little knowledge is available on the mechanisms stabilizing organic C in Arctic soils besides impaired decomposition due to low temperatures. To gain such knowledge, we investigated soils from Samoylov Island in the Lena River delta with respect to the composition and distribution of organic C among differently stabilized SOM fractions. The soils were fractionated according to density and particle size to obtain differently stabilized SOM fractions differing in chemical composition and thus bioavailability. To better understand the chemical alterations from plant-derived organic particles in these soils rich in fibrous plant residues to mineral-associated SOM, we analyzed the elemental, isotopic and chemical composition of particulate OM (POM) and clay-sized mineral-associated OM (MAOM). We demonstrate that the SOM fractions that contribute with about 17 kg C m−3 for more than 60 % of the C stock are highly bioavailable and that most of this labile C can be assumed to be prone to mineralization under warming conditions. Thus, the amount of relatively stable, small occluded POM and clay-sized MAOM that currently accounts with about 10 kg C m−3 for about 40 % of the C stock will most probably be crucial for the quantity of C protected from mineralization in these Arctic soils in a warmer future. Using δ15N as a proxy for nitrogen (N) balances indicated an important role of N inputs by biological N fixation, while gaseous N losses appeared less important. However, this could change, as with about 0.4 kg N m−3 one third of the N is present in bioavailable SOM fractions, which could lead to increases in mineral N cycling and associated N losses under global warming. Our results highlight the vulnerability of SOM in Arctic permafrost-affected soils under rising temperatures, potentially leading to unparalleled greenhouse gas emissions from these soils.

show abstract

Soil organic matter is stabilized by organo-mineral associations through two key processes: The role of the carbon to nitrogen ratio

Cited by 137 publications

References 45 publications

Increasing temperature can modify the effect of straw mulching on soil C fractions, soil respiration, and microbial community composition

Increasing temperature can modify the effect of straw mulching on soil C fractions, soil respiration, and microbial community composition

From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils

From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils

Contact Info

Product

Resources

About