Soil-air partitioning of semivolatile organic compounds in the Lesser Himalaya region: Influence of soil organic matter, atmospheric transport processes and secondary emissions

2021 ◽  
pp. 118006
Author(s):  
Rahat Riaz ◽  
Riffat Naseem Malik ◽  
Cynthia A. de Wit
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Compounds ◽  
Atmospheric Transport ◽  
Transport Processes ◽  
Semivolatile Organic Compounds ◽  
Lesser Himalaya ◽  
Soil Air

Spatial Arrangement of Organic Compounds on a Model Mineral Surface: Implications for Soil Organic Matter Stabilization

2013 ◽  
Vol 48 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Loukas Petridis ◽  
Haile Ambaye ◽  
Sindhu Jagadamma ◽  
S. Michael Kilbey ◽  
Bradley S. Lokitz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Compounds ◽  
Spatial Arrangement ◽  
Mineral Surface ◽  
Organic Matter Stabilization

Parts of a Soil (Soil Constituents) Air, Water, Minerals, and Organic Matter

1999 ◽  
Author(s):  
Robert F. Keefer
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Plant Growth ◽  
Soil Water ◽  
Fine Particles ◽  
Pore Space ◽  
Mineral Matter ◽  
Soil Air ◽  
Secondary Minerals ◽  
Primary Minerals

Soils physically consist of soil solids and pore space. Soil solids are composed of (a) mineral matter such as sand (coarse particles), silt (fine particles), and clay (very fine particles), and (b) soil organic matter, like decaying plant, animal, and microbial remains, along with microbial synthates. The pore space is occupied by soil air and soil water, each of which has a different makeup than atmospheric air and rainwater. Soil air often has more carbon dioxide and gases of nitrogen and sulfur compounds. Soil water has much more dissolved substances in it than rainwater. Soil solids occupy about 50% of a soil. They are made up of about 45% mineral matter and about 5% organic matter, but these proportions vary greatly. Soil mineral matter consists of very coarse rocks (primary minerals) and the three main soil parts: . . . 1. Coarse—Sand (a primary mineral, silicon dioxide) 2. Fine—Silts (both primary or secondary minerals) 3. Very Fine—Clays (secondary minerals) . . . Soil organic matter consists of plant and animal remains (in various stages of decomposition), microorganisms, and compounds synthesized by microorganisms. Soil pore space occupies about 50% of a soil and consists of the open space occupied by either air or water. The proportions of air and water that are present can greatly influence plant growth. Soil air is necessary for plants to grow, but if this component dominates, drought occurs and plant growth suffers. Soil water is also necessary for plant growth, but if this component dominates, flooding occurs and plant growth also suffers as most plants require a supply of oxygen. Soil consists of natural elements, for example, Si, Al, Fe, Ca, Mg, Na, K, Ti, P, and others. Often the elements are present in oxides, sulfides, silicates, and other combinations. These elements or their combined form are present as rocks (primary minerals), clays (secondary minerals), and available nutrients for plants. Soil contains many life forms.

scholarly journals The Influence of Soil Organic Matter Age Spectrum on the Reconstruction of Atmospheric 14C Levels Via Stalagmites

Radiocarbon ◽  
2011 ◽  
Vol 53 (1) ◽  
pp. 99-115 ◽  
Author(s):  
J Fohlmeister ◽  
B Kromer ◽  
A Mangini
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Calibration Curve ◽  
Set Covering ◽  
Vegetation Density ◽  
Data Set ◽  
Soil Air ◽  
Ne Italy ◽  
Karst Model ◽  
The Impact

The imprint of the radiocarbon bomb peak was detected in the top of stalagmite ER-77 from Grotta di Ernesto (NE Italy). This recently grown stalagmite reveals a reservoir age, also known as dead carbon fraction (dcf), of ≃1050 14C yr, or 12%. By applying a 14C soil-karst model, the age spectrum of soil organic matter (SOM) as well as the CO2 contribution of the single SOM reservoirs to the total soil CO2 can be derived. Under the assumption of constant vegetation, meaning both vegetation density and the age spectrum of SOM, it is possible to derive the soil-air 14C activity of the past using the 14C calibration curve (IntCal04). Hence, it is also possible to calculate an artificial stalagmite 14C data set covering the last 25,000 yr with parameters determined for stalagmite ER-77. With this artificially constructed data set, we derived the hypothetical atmospheric 14C activity by using the common method of applying a constant dcf on the modeled 14C data set of the stalagmite. This theoretical approach allows to analyze the impact of a constant and variable SOM age spectrum on atmospheric 14C reconstructions performed with real stalagmite 14C measurements. We observe deviations between IntCal04 and the atmospheric 14C activity as derived with our modeled 14C data set, which are larger for older SOM than for younger SOM and vary in time up to 2 pMC, depending on the strength of the variations in the atmospheric 14C level. This value is comparable with the 1-σ uncertainty given by IntCal04 for the last glacial. For a varying SOM age spectrum, the deviations between the calibration curve and 14C level of the atmosphere reconstructed with a stalagmite exceed 3 pMC, which is larger than the 1-σ uncertainty of IntCal04. In general, the SOM has smoothing, shifting, and 14C-depleting effects on the stalagmite 14C record and, therefore, on the stalagmite-derived atmospheric 14C activity. In this study, changes in soil-air pCO2 and carbonate dissolution conditions, which have also an important impact on the 14C record of a stalagmite, are not accounted for.

Sorption of anthropogenic organic compounds by soil organic matter: a mechanistic consideration

2001 ◽  
Vol 81 (3) ◽  
pp. 317-323 ◽  
Author(s):  
Baoshan Xing
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Compounds ◽  
High Surface ◽  
High Surface Area ◽  
Fate And Transport ◽  
Dual Mode ◽  
Subsurface Environments ◽  
Desorption Hysteresis ◽  
Sorption Mechanisms

Sorption experiments with apolar organic compounds (naphthalene and 1,2-dichorobenzene) were conducted to evaluate sorption mechanisms in soil organic matter (SOM). All isotherms were nonlinear and competition between solutes was observed. Nonlinearity and competition increased in an order of peat humic acid (HA) < peat < peat humin. Isotherms of Al-saturated HA (Al-HA) were more nonlinear than untreated HA and Ca-HA, and sorption/desorption hysteresis occurred only in Al-HA. These results are not consistent with partitioning theory or the presence of high-surface-area carbonaceous materials (HSACM) in soil. But the results are consistent with dual-mode sorption, where SOM is postulated to have both condensed (rigid) and expanded (flexible) domains, and adsorption takes place only in the condensed domains and partitioning in both domains. These non-ideal sorptive behaviors need to be incorporated into predictive models to more accurately describe the fate and transport of organics in soil and subsurface environments. Key words: sorption, organic compounds, organic matter, dual-mode, partition, mechanisms

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