scholarly journals Scenario modelling of carbon mineralization in 3D soil architecture at the microscale: toward an accessibility coefficient of organic matter for bacteria

2021 ◽  
Author(s):  
Bruno Mbé ◽  
Olivier Monga ◽  
Valérie Pot ◽  
Wilfred Otten ◽  
Frédéric Hecht ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Mineralization ◽  
Scenario Modelling

scholarly journals Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea)

2011 ◽  
Vol 8 (1) ◽  
pp. 549-592 ◽  
Author(s):  
L. Pastor ◽  
C. Cathalot ◽  
B. Deflandre ◽  
E. Viollier ◽  
K. Soetaert ◽  
...  
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Continental Shelf ◽  
Carbon Mineralization ◽  
River Mouth ◽  
Total Carbon ◽  
Large Contribution ◽  
Organic Carbon Content ◽  
Rhône River ◽  
Rhone River

Abstract. In-situ oxygen microprofiles, sediment organic carbon content and pore-water concentrations of nitrate, ammonium, iron, manganese and sulfides obtained in sediments from the Rhône River prodelta and its adjacent continental shelf were used to constrain a numerical diagenetic model. Results showed that (1) organic matter from the Rhône River is composed of a fraction of fresh material associated to high first-order degradation rate constants (11–33 yr−1), (2) burial efficiency (burial/input ratio) in the Rhône prodelta (within 3 km of the river outlet) can be up to 80%, and decreases to ~20% on the adjacent continental shelf 10–15 km further offshore (3) there is a large contribution of anoxic processes to total mineralization in sediments near the river mouth, certainly due to large inputs of fresh organic material combined with high sedimentation rates, (4) diagenetic by-products originally produced during anoxic organic matter mineralization are almost entirely precipitated (>97%) and buried in the sediment, which leads to (5) a low contribution of the re-oxidation of reduced products to total oxygen consumption. Consequently, total carbon mineralization rates as based on oxygen consumption rates and using Redfield stoichiometry can be largely underestimated in such River Ocean dominated Margins (RiOMar) environments.

Redox control on carbon mineralization and dissolved organic matter along a chronosequence of paddy soils

2013 ◽  
Vol 64 (4) ◽  
pp. 476-487 ◽  
Author(s):  
A. Hanke ◽  
C. Cerli ◽  
J. Muhr ◽  
W. Borken ◽  
K. Kalbitz
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Carbon Mineralization ◽  
Paddy Soils ◽  
Redox Control

Precipitation of enzymes and organic matter by aluminum-Impacts on carbon mineralization

2008 ◽  
Vol 171 (6) ◽  
pp. 900-907 ◽  
Author(s):  
Thorsten Scheel ◽  
Karin Pritsch ◽  
Michael Schloter ◽  
Karsten Kalbitz
Keyword(s):  
Organic Matter ◽  
Carbon Mineralization

scholarly journals Land use impact on carbon mineralization is mainly caused by variation of particulate organic matter content rather than of soil structure

2021 ◽  
Author(s):  
Steffen Schlüter ◽  
Tim Roussety ◽  
Lena Rohe ◽  
Vusal Guliyev ◽  
Evgenia Blagodatskaya ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Particulate Organic Matter ◽  
Soil Structure ◽  
Predictive Power ◽  
Carbon Mineralization ◽  
Basal Respiration ◽  
Microstructural Properties ◽  
Soil Functions ◽  
Microbial Hotspots

Abstract. Land use is known to exert a dominant impact on a range of essential soil functions like water retention, carbon sequestration, matter cycling and plant growth. At the same time, land use management is known to have a strong influence on soil structure, e.g. through bioturbation, tillage and compaction. However, it is often unclear whether differences in soil structure are the actual cause for differences in soil functions or just co-occurring. This impact of land use (conventional and organic farming, intensive and extensive meadow, extensive pasture) on the relationship between soil structure and short-term carbon mineralization was investigated at the Global Change Exploratory Facility, in Bad Lauchstädt, Germany. Intact topsoil cores (n = 75) were sampled from each land use type at the early growing season. Soil structure and microbial activity were measured using X-ray computed tomography and respirometry, respectively. Grasslands had a greater microbial activity than croplands, both in terms of basal respiration and rate of carbon mineralization during growth. This was caused by a larger amount of particulate organic matter (POM) in the topsoil of grasslands. The frequently postulated dependency of basal respiration on soil moisture was absent even though some cores were apparently water limited. This finding was related to microenvironments shaping microbial hotspots where the decomposition of plant residues was obviously decoupled from water limitation in bulk soil. Differences in microstructural properties between land uses were surprisingly small, mainly due huge variability induced by patterns of compacted clods and loose areas caused by tillage in cropland soils. The most striking difference was larger macropore diameters in grasslands soil due to the presence of large biopores that are periodically destroyed in croplands. Variability of basal respiration among all soil cores amounted to more than one order of magnitude (0.08–1.42 µg CO2-C h−1 g−1 soil) and was best described by POM mass (R2 = 0.53, p < 0.001). Predictive power was hardly improved by considering all bulk, microstructure and microbial properties jointly. The predictive power of image-derived microstructural properties was low, because aeration was not limiting carbon mineralization and was sustained by pores smaller than the image resolution limit (< 30 µm). The rate of glucose mineralization during growth was explained well by substrate-induced respiration (R2 = 0.84) prior to growth, which was in turn correlated with total microbial biomass, basal respiration and POM mass and again not affected by pore metrics. These findings stress that soil structure had little relevance in predicting carbon mineralization in well-aerated soil, as this predominantly took place in microbial hotspots around degrading POM that was detached from the pore structure and moisture of the bulk soil. Land use therefore affects carbon mineralization in well-aerated soil mainly by the amount and quality of labile carbon.

Biogeochemical carbon transformations in a drained coastal peatland of the southern Baltic Sea: An isotope and trace element perspective

2021 ◽  
Author(s):  
Anna-Kathrina Jenner ◽  
Iris Schmiedinger ◽  
Jens Kallmeyer ◽  
Cordula Gutekunst ◽  
Gerald Jurasinski ◽  
...  
Keyword(s):  
Organic Matter ◽  
Trace Metals ◽  
Baltic Sea ◽  
Pore Water ◽  
Research Training ◽  
Isotope Composition ◽  
Carbon Mineralization ◽  
Training Group ◽  
Iron Cycling ◽  
Coast Line

&lt;p&gt;Peatlands serve as important ecosystems since they store a substantial fraction of global soil carbon. Through draining the internal biogeochemical processes may be changed impacting the transformation of stored carbon and plant material. Pristine peatlands are primarily associated with methanogenic and iron-cycling conditions, however, minor sulfur cycling may contribute to carbon mineralization in these ecosystems depending on the amount of atmospheric sulfur deposition and accumulation. In near coastal peatlands the element budget may be altered through natural or artificial flooding by brackish/marine waters. When introducing sulfate-bearing solutions, the concentrations of electron acceptors for anaerobic mineralization or organic matter increase when compared to fresh water conditions. The investigated area is planned to be flooded by Baltic Sea coastal waters in the near future.&lt;/p&gt;&lt;p&gt;Here we present results from a study from a drained peatland located in the southern part of the Baltic Sea. In the past the area was agriculturally used as grassland. Soil cores were retrieved along a transect perpendicular to the coast line for (isotope) biogeochemical analyses of pore water and solid phases. Analyses included the CNS composition of soils, and dissolved major elements, nutrients, sulphide, trace metals and stable isotopes of water, DIC, and sulfate (H, O, C, S). Furthermore, acid-extractions of metals were carried out to identify zones of dissolution and formation of authigenic phases. For quantification of microbial sulphate reduction rates (SRR) additional cores were retrieved and SRR were measured in whole-core incubations.&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;The pore water isotopic composition is close to the local meteoric water line at the German Baltic Seas coast line. Concentration and stable isotope composition of DIC indicate mineralization of C3 type organic matter. Pore water trace metals content indicates the importance of anaerobic mineralization for release of metals into the pore and surface waters.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Acknowledgement: This study is supported by the DFG research training group BALTIC TRANSCOAST and Leibniz IOW.&lt;/p&gt;

Carbon Mineralization and Inorganic Nitrogen Pools under Terminalia chebula Retz.-Based Agroforestry System in Himalayan Foothills, India

2020 ◽  
Vol 66 (5) ◽  
pp. 634-643
Author(s):  
Amit Kumar ◽  
Gopal Krishna Dwivedi ◽  
Salil Tewari ◽  
Jai Paul ◽  
Rahul Anand ◽  
...  
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
Nutrient Management ◽  
Inorganic Nitrogen ◽  
Carbon Mineralization ◽  
Agroforestry System ◽  
Himalayan Region ◽  
Inorganic N ◽  
Nutrient Sources ◽  
Himalayan Foothills

Abstract Soil organic matter is major terrestrial pool for soil organic carbon (C) and nitrogen (N), and their decomposition is sensitive to vegetation and climate change. Integrated nutrient management (INM) deals with the combined application of chemical fertilizers and organic manures for nutritional requirement of crops and avoid the adverse effect of long-term application of chemical fertilizer on crop production and their sustainability. The present study was carried out to investigate the influence of different nutrient sources on soil C mineralization and inorganic N pools in a Terminalia chebula Retz, based on a agroforestry system. The results showed that the highest CO2 evolution was recorded in 100 percent INM and minimum in farmyard manure treatment after 120 days of incubation. Inorganic N was higher under the agroforestry system than under the open system. Among the different nutrient sources, the highest inorganic N was recorded in a 100 percent INM nutrient source and minimal in wheat straw treatment. The yield of turmeric was higher under the T. chebula-based agroforestry system (20.87 t ha–1) than under the open system (19.27 t ha–1). Results suggest that agroforestry systems using the INM approach can enhance C mineralization and inorganic N concentration with improved crop productivity in the Himalayan foothills. Study Implications: Fertilizer has been used since ancient times, and if well managed it can be an asset, promoting sustainable agriculture and increasing crop production, particularly for smallholder farmers in the Himalayan region of India. We compared fertilizer application practices under an agroforestry system in a representative Himalayan region of India. The majority of farmers in the region of the Himalayan foothills having marginal land and they are not able to produce optimum food grains for their requirement. However, their demands are increasing day by day, so to fulfill their demand, they have to adopt agroforestry. Agroforestry may be fulfilling their demand in terms of food, fuel, fodder, and other intangible benefits. Moreover, to increase the production under agroforestry, we have to apply organic and inorganic fertilizer in the soil either as the sole application or as a combination of these fertilizers. The application of these fertilizers will improve the productivity and fertility of land, especially carbon mineralization and inorganic nitrogen. These two soil properties are important to study because these are limiting to land productivity. In addition, efforts to improve integrated nutrient management in the Himalayan region of India would strengthen farmers’ incomes by strengthening land fertility and productivity. The rapid increase in human population over the last century is putting a massive pressure on existing resources, namely soil and water, resulting in environmental degradation in some regions around the world. As productive land becomes scarce, marginalized farmers are pushed into fragile croplands and forest lands unsuitable for modern agriculture which, in turn, is vulnerable, to degradation. If the present trend in population growth persists, pasture and forest lands will be further reduced (Satterthwaite et al. 2010). At this stage, the value of growing trees becomes more significant, and participation in tree planting schemes should be encouraged. However, this option is most feasible when combined with agriculture. As a result, agroforestry is an important management strategy that not only helps to meet the world food requirements but also helps to protect soil from degradation (Ram et al. 2017) and can enhance soil organic matter levels by adding the quantity of above- and below-ground organic matter inputs to soils (Nair et al. 2009, Marone et al. 2017).

scholarly journals Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment

2018 ◽  
Vol 15 (2) ◽  
pp. 471-490 ◽  
Author(s):  
Volker Brüchert ◽  
Lisa Bröder ◽  
Joanna E. Sawicka ◽  
Tommaso Tesi ◽  
Samantha P. Joye ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Mineralization ◽  
Laptev Sea ◽  
East Siberian Sea ◽  
Degradation Rates ◽  
Siberian Arctic ◽  
Sediment Carbon ◽  
The Laptev Sea ◽  
Carbon Contribution

Abstract. The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O2 microelectrode profiling; intact sediment core incubations; 35S-sulfate tracer experiments; pore-water dissolved inorganic carbon (DIC); δ13CDIC; and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope and allows us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 84 % of the depth-integrated carbon mineralization. Oxygen uptake rates and anaerobic carbon mineralization rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC ∕ NH4+ ratios in pore waters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end-member calculations, the terrestrial organic carbon contribution varied between 32 and 36 %, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using isotope end-member apportionment over the outer shelf of the Laptev and East Siberian seas suggests that about 16 Tg C yr−1 is respired in the outer shelf seafloor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3 Tg C yr−1 is degraded by anaerobic processes, with a terrestrial organic carbon contribution ranging between 0.3 and 0.5 Tg yr−1.

Effect of crop rotations and rotation phase on characteristics of soil organic matter in a Dark Brown Chernozemic soil

1992 ◽  
Vol 72 (4) ◽  
pp. 403-416 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
R. P. Zentner ◽  
S. A. Brandt ◽  
M. Schnitzer
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Respiratory Activity ◽  
Carbon Mineralization ◽  
Crop Rotations ◽  
Organic N ◽  
Microbial Biomass C ◽  
Rotation Phase

The influence of five crop rotations and the rotation phases (i.e., rotation-yr) on some soil organic matter characteristics was investigated in a long-term (23 yr) study carried out on an Orthic Dark Brown Chernozemic soil at Scott, Saskatchewan. The cropping systems included different cropping frequencies and crop types (cereals, oilseeds, and legume-hay). Soil samples were taken from the 0- to 7.5- and 7.5- to 15-cm depths in mid-September 1988, 2 wk after harvest of the grain crops (i.e., 2 mo after hay harvest and plowdown). Most effects of rotations, and rotation phases, on soil biological characteristics assessed, were significant primarily in the top 7.5-cm soil depth. Increasing the cropping frequency did not increase soil organic matter. Excessive preseeding tillage of stubble plots may have masked any potential advantage provided by frequent cropping. Including alfalfa (Medicago sativa L.) hay crops in rotation with grain crops decreased soil organic matter in the fallow and grain crop rotation phases of rotations. This was likely due to increased moisture stress depressing associated cereal production in this semiarid environment. As expected, rotation phase did not influence soil organic C, but alfalfa under-seeded into barley (Hordeum vulgare L.) increased soil organic nitrogen. We believe this was due to crop residue inputs from the seedling alfalfa. Microbial biomass C and N, C mineralization, the specific respiratory activity (ratio of CO2-C respired/microbial biomass C) and hydrolyzable amino acids were also greater in the rotation phases in which barley was underseeded with alfalfa. Carbon mineralization and specific respiratory activity were directly related to estimated crop residue-C returned to soil, but not residue-N. However, both were increased by including alfalfa in the rotation. Carbon mineralization and specific respiratory activity were more sensitive indexes of soil organic matter quality than biomass C and N per se. Hydrolyzable amino acids and amino sugars responded to the treatments in a manner similar to total soil organic N. Relative molar distribution of amino acids was unaffected by crop rotation or rotation phase. Potentially mineralizable N in this soil was low compared to other Canadian prairie soils, even though the total soil organic N of the Scott soil was relatively high. We concluded that (i) all soil biochemical characteristics studied are useful for assessing soil quality changes; (ii) when studying soil changes, thin (0- to 7.5-cm) soil slices are more likely to reveal treatment effects than thicker slices; (iii) all rotation phases should be analyzed whenever forage legumes are constituents of crop rotations. Key words: C mineralization; microbial biomass, amino acids, N mineralization, specific respiratory activity

scholarly journals Microbiological activity and carbon mineralization in pampean soils with different agricultural use intensity

2015 ◽  
Author(s):  
Ricardo A Castro-Huerta ◽  
Fernando R Momo ◽  
Liliana B Falco ◽  
César A Di Ciocco ◽  
Carlos E Coviella
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Enzymatic Activity ◽  
Microbial Biomass Carbon ◽  
Carbon Mineralization ◽  
Terrestrial Ecosystems ◽  
Mineralization Rate ◽  
Microbial Quotient ◽  
Agricultural Use

The processes involved in the flows of matter and energy of terrestrial ecosystems depends heavily on soil biological activity, the current conventional agricultural managements could alter the biological mechanisms involved in decomposition and nutrient cycling in agroecosystems. The aim of this study was to compare the activity levels and soil microbial biomass between different agricultural pampean soil uses and its relationship to carbon mineralization. 25 years of agricultural use were compared with 25 years of ecological reserve naturalized where each agroecosystem soil were collected at 61 - 125 - 183 - 236 - 302 - 368 - 431 - 488 days for measuring their moisture, organic matter, enzymatic activity, microbial biomass carbon, soil respiration, metabolic quotient, microbial quotient and carbon mineralization rate. The distance between agroecosystems is less than 800 m, thus assuming the same soil and climatic conditions. The data were evaluated by Friedman test finding significant differences in moisture, organic matter, enzymatic activity, soil respiration y microbial quotient (p< 0.01). Difference was also found in the microbial mineralization rate of carbon (p< 0.1).

Sign in / Sign up

Export Citation Format

Share Document