Carbon Isotope Measurements to Determine the Turnover of Soil Organic Matter Fractions in a Temperate Forest Soil

Soil organic matter (SOM) is a combination of materials having different origin and with different stabilization and decomposition processes. To determine the different SOM pools and their turnover rates, a silt loam-textured Luvisol from West Hungary was taken from the 0–20 cm soil depth and incubated for 163 days. Maize residues were added to the soil in order to obtain natural 13C enrichment. Four different SOM fractions—particulate organic matter (POM), sand and stable aggregate (S + A), silt- plus clay-sized (s + c) and chemically resistant soil organic carbon (rSOC) fractions—were separated and analyzed using FT-IR, δ13C, and 14C measurements. The mean residence time (MRT) of the new C and the proportion of maize-derived C in the fractions were calculated. The POM fraction was found to be the most labile C pool, as shown by the easily decomposable chemical structures (e.g., aliphatic, O-alkyl, and polysaccharides), the highest proportion (11.7 ± 2.5%) of maize-derived C, and an MRT of 3.6 years. The results revealed that the most stable fraction was the rSOC fraction which had the smallest proportion of maize-derived C (0.18 ± 2.5%) and the highest MRT (250 years), while it was the only fraction with a negative value of Δ14C (−75.0 ± 2.4‰). Overall, the study confirmed the hypothesis that the SOM associated with finer-sized soil particles decomposes the least, highlighting the significance of the fractionation process for more accurate determination of the decomposition processes of SOM pools.

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Influence of animal manure application on the chemical structures of soil organic matter as investigated by advanced solid-state NMR and FT-IR spectroscopy

Geoderma ◽

10.1016/j.geoderma.2008.06.003 ◽

2008 ◽

Vol 146 (1-2) ◽

pp. 353-362 ◽

Cited By ~ 77

Author(s):

Jingdong Mao ◽

Dan C. Olk ◽

Xiaowen Fang ◽

Zhongqi He ◽

Klaus Schmidt-Rohr

Keyword(s):

Organic Matter ◽

Solid State ◽

Soil Organic Matter ◽

Ir Spectroscopy ◽

Solid State Nmr ◽

Animal Manure ◽

Manure Application ◽

Chemical Structures ◽

Ft Ir ◽

Ft Ir Spectroscopy

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Soil Organic Matter Fractions under Managed Pine Plantations of the Southeastern USA

Soil Science Society of America Journal ◽

10.2136/sssaj2004.0950 ◽

2004 ◽

Vol 68 (3) ◽

pp. 950 ◽

Cited By ~ 12

Author(s):

Marietta E. Echeverría ◽

Daniel Markewitz ◽

Lawrence A. Morris ◽

Ronald L. Hendrick

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Pine Plantations ◽

Southeastern Usa ◽

Soil Organic Matter Fractions ◽

Organic Matter Fractions

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The Soil Organic Matter in Connection with Soil Properties and Soil Inputs

Agronomy ◽

10.3390/agronomy11040779 ◽

2021 ◽

Vol 11 (4) ◽

pp. 779

Author(s):

Václav Voltr ◽

Ladislav Menšík ◽

Lukáš Hlisnikovský ◽

Martin Hruška ◽

Eduard Pokorný ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Texture ◽

Management Practices ◽

Soil Depth ◽

Operating Conditions ◽

Hot Water ◽

Natural Soil ◽

Soil Productivity ◽

Linear Regression Models

The content of organic matter in the soil, its labile (hot water extractable carbon–HWEC) and stable (soil organic carbon–SOC) form is a fundamental factor affecting soil productivity and health. The current research in soil organic matter (SOM) is focused on individual fragmented approaches and comprehensive evaluation of HWEC and SOC changes. The present state of the soil together with soil’s management practices are usually monitoring today but there has not been any common model for both that has been published. Our approach should help to assess the changes in HWEC and SOC content depending on the physico-chemical properties and soil´s management practices (e.g., digestate application, livestock and mineral fertilisers, post-harvest residues, etc.). The one- and multidimensional linear regressions were used. Data were obtained from the various soil´s climatic conditions (68 localities) of the Czech Republic. The Czech farms in operating conditions were observed during the period 2008–2018. The obtained results of ll monitored experimental sites showed increasing in the SOC content, while the HWEC content has decreased. Furthermore, a decline in pH and soil´s saturation was documented by regression modelling. Mainly digestate application was responsible for this negative consequence across all soils in studied climatic regions. The multivariate linear regression models (MLR) also showed that HWEC content is significantly affected by natural soil fertility (soil type), phosphorus content (−30%), digestate application (+29%), saturation of the soil sorption complex (SEBCT, 21%) and the dose of total nitrogen (N) applied into the soil (−20%). Here we report that the labile forms (HWEC) are affected by the application of digestate (15%), the soil saturation (37%), the application of mineral potassium (−7%), soil pH (−14%) and the overall condition of the soil (−27%). The stable components (SOM) are affected by the content of HWEC (17%), soil texture 0.01–0.001mm (10%), and input of organic matter and nutrients from animal production (10%). Results also showed that the mineral fertilization has a negative effect (−14%), together with the soil depth (−11%), and the soil texture 0.25–2 mm (−21%) on SOM. Using modern statistical procedures (MRLs) it was confirmed that SOM plays an important role in maintaining resp. improving soil physical, biochemical and biological properties, which is particularly important to ensure the productivity of agroecosystems (soil quality and health) and to future food security.

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Dating of Prehistoric Burial Mounds by 14C Analysis of Soil Organic Matter Fractions

Radiocarbon ◽

10.1017/s0033822200032434 ◽

2003 ◽

Vol 45 (1) ◽

pp. 101-112 ◽

Cited By ~ 27

Author(s):

Søren M Kristiansen ◽

Kristian Dalsgaard ◽

Mads K Holst ◽

Bent Aaby ◽

Jan Heinemeier

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Soil Science ◽

Ams Dating ◽

Buried Soil ◽

Archaeological Artifacts ◽

Burial Mounds ◽

Organic Matter Fractions ◽

Age Estimates ◽

Organic Remains

Dating of prehistoric anthropogenic earthworks requires either excavation for archaeological artifacts or macroscopic organic matter suitable for 14C analysis. Yet, the former, in many cases, is undesirable and the latter is difficult to obtain. Here we present a soil science procedure, which has the potential to overcome these problems. It includes careful sampling of buried former soil surfaces, acid-alkali-acid fractionation of soil organic matter (SOM), and subsequent 14C AMS dating. To test the procedure, soil from one of the largest known burial mounds in Scandinavia, Hohøj, and 9 other Danish burial mounds were sampled. The 14C dates from extracted SOM fractions were compared to reference ages obtained by other methods. We show that humic acid fractions in 7 of the 10 mounds had the same age as the reference, or were, at maximum, 280 yr older than the reference ages. The best age estimates were derived from an organic-rich layer from the upper cm of buried soil or sod. Differences among SOM fraction ages probably indicate the reliability of the dating. Hohøj dated to approximately 1400 BC and, thus, was up to 500 yr older than other dated Scandinavian mounds of comparable size. The remaining investigated burial mounds were dated to between 1700 and 1250 BC. We conclude that combined sampling of buried soil surfaces, SOM fractionation, and 14C analysis allows for dating of archaeological earthworks when minimal disturbance is required, or if no macroscopic organic remains are found.

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Impact of Gliricidia sepium intercropping on soil organic matter fractions in a maize-based cropping system

Agriculture Ecosystems & Environment ◽

10.1016/j.agee.2010.04.008 ◽

2010 ◽

Vol 138 (3-4) ◽

pp. 139-146 ◽

Cited By ~ 56

Author(s):

T.L. Beedy ◽

S.S. Snapp ◽

F.K. Akinnifesi ◽

G.W. Sileshi

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Cropping System ◽

Gliricidia Sepium ◽

Soil Organic Matter Fractions ◽

Organic Matter Fractions

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Long residence times of rapidly decomposable soil organic matter: application of a multi-phase, multi-component, and vertically-resolved model (TOUGHREACTv1) to soil carbon dynamics

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-815-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 815-870 ◽

Cited By ~ 6

Author(s):

W. J. Riley ◽

F. M. Maggi ◽

M. Kleber ◽

M. S. Torn ◽

J. Y. Tang ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Reactive Transport ◽

Lignin Content ◽

Sensitivity Analyses ◽

Rooting Depth ◽

Carbon Substrate ◽

Advective Transport ◽

Turnover Rates ◽

Multi Phase

Abstract. Accurate representation of soil organic matter (SOM) dynamics in Earth System Models is critical for future climate prediction, yet large uncertainties exist regarding how, and to what extent, the suite of proposed relevant mechanisms should be included. To investigate how various mechanisms interact to influence SOM storage and dynamics, we developed a SOM reaction network integrated in a one-dimensional, multi-phase, and multi-component reactive transport solver. The model includes representations of bacterial and fungal activity, multiple archetypal polymeric and monomeric carbon substrate groups, aqueous chemistry, aqueous advection and diffusion, gaseous diffusion, and adsorption (and protection) and desorption from the soil mineral phase. The model predictions reasonably matched observed depth-resolved SOM and dissolved organic carbon (DOC) stocks in grassland ecosystems as well as lignin content and fungi to aerobic bacteria ratios. We performed a suite of sensitivity analyses under equilibrium and dynamic conditions to examine the role of dynamic sorption, microbial assimilation rates, and carbon inputs. To our knowledge, observations do not exist to fully test such a complicated model structure or to test the hypotheses used to explain observations of substantial storage of very old SOM below the rooting depth. Nevertheless, we demonstrated that a reasonable combination of sorption parameters, microbial biomass and necromass dynamics, and advective transport can match observations without resorting to an arbitrary depth-dependent decline in SOM turnover rates, as is often done. We conclude that, contrary to assertions derived from existing turnover time based model formulations, observed carbon content and δ14C vertical profiles are consistent with a representation of SOM dynamics consisting of (1) carbon compounds without designated intrinsic turnover times, (2) vertical aqueous transport, and (3) dynamic protection on mineral surfaces.

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