The ignition at low temperatures of the organic matter in soils

1938 ◽  
Vol 28 (3) ◽  
pp. 393-400 ◽  
Author(s):  
J. S. Hosking
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Low Temperature ◽  
Low Temperatures ◽  
Carbonaceous Material ◽  
Volatile Constituents ◽  
Final Reaction ◽  
Major Reaction ◽  
Residual Organic Matter

The low temperature ignition of soil organic matter has been investigated for temperatures ranging from 100 to 500° C.Appreciable losses are found to occur below 100° C.; up to 200° C. heating results essentially in the distillation of volatile constituents, while between this temperature and 300° C. destructive distillation is the major reaction. These reactions are responsible for the removal of 85% of the soil organic matter.By 300° C. the greater part of the residual organic matter consists of carbonaceous material, and the final reaction is simple ignition of this material.Two hours’ heating of the soil at 450° C. or about half an hour at 500° C. are recommended for the removal of 99% of the soil organic matter.

The Conceptual Basis of LTER Studies in the Alaskan Boreal Forest

2006 ◽  
Author(s):  
John Yarie ◽  
Leslie A. Viereck
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Low Temperature ◽  
Boreal Forest ◽  
General Circulation ◽  
Global Climate ◽  
Northern Eurasia ◽  
Global Changes ◽  
Moisture Regime ◽  
Organic Layers

The boreal forest occupies 10% of the ice-free terrestrial surface and is the second most extensive terrestrial biome on Earth, after tropical forests (Saugier et al. 2001). It is a land of extremes: low temperature and precipitation, low diversity of dominant plant species, dramatic population fluctuations of important insects and mammals, and a generally sparse human population. The boreal forest is also a land poised for change. During the last third of the twentieth century, many areas of the boreal forest, such as western North America and northern Eurasia, warmed more rapidly than any other region on Earth (Serreze et al. 2000). This pattern of warming is consistent with projections of general circulation models. These models project that human-induced increases in greenhouse gases, such as carbon dioxide, will cause the global climate to warm and that the warming will occur most rapidly at high latitudes (Ramaswamy et al. 2001). If we accept the projections of these models, the climate of many parts of the boreal forest will likely continue to warm even more rapidly than it has in the past. The ecological characteristics of the boreal forest render it vulnerable to warming and other global changes. Because the boreal forest is the coldest forested biome on Earth, organisms are adapted to low temperatures, and many of its physical and biological processes are molded by low temperature. Permafrost (permanently frozen ground) is widespread and governs the soil temperature and moisture regime of a large proportion of the boreal forest. Yet permafrost temperatures are close to the freezing point throughout much of interior Alaska (Osterkamp and Romanovsky 1999), so only a slight warming of soils could greatly reduce the extent of permafrost. Low temperature and anaerobic soil conditions associated with permafrost-impeded drainage constrain decomposition rate, leading to thick layers of soil organic matter. Consequently, boreal soils account for about a third of the readily decomposable soil organic matter on Earth (McGuire et al. 1995). This represents a quantity of carbon similar to that in the atmosphere. Fire is another process that could rapidly return this undecomposed carbon from the organic layers of the soil to the atmosphere.

Impact of biochar amendment on soil organic matter composition in a heavy-metals polluted soil

2021 ◽  
Author(s):  
Arturo Santa-Olalla ◽  
Elena Fernandez-Boy ◽  
Paloma Campos ◽  
Heike Knicker ◽  
Rafael Lopez ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Trace Elements ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Carbonaceous Material ◽  
Water Holding Capacity ◽  
The European Union ◽  
European Environmental Agency ◽  
Water Holding ◽  
Biochar Amendment

<p>It is estimated that over 37 % of degraded soils in the European Union are polluted by heavy metals [1], which are non-biodegradable and persistent pollutants in soils. The application of organic amendments to soils for their remediation has been worldwide used [2]. Several studies have shown that biochar, the carbonaceous material produced by pyrolysis of organic residues, has a high potential to stabilize trace elements in soils [3]. Biochars usually have an alkaline pH and high water holding capacity (WHC), large specific surface area and cation exchange capacity, which are appropriate characteristics to reduce the availability of heavy metals in the environment [4]. Nevertheless, recent studies exhibited that biochar recalcitrance could be much lower than assumed [5].  Beside this, the effects of the addition of biochar as a soil amendment on the composition of soil organic matter (SOM) are largely unknown. Thus, the aim of this study is to investigate the effects of the application of biochars from rice husk (RHB) and olive pit (OPB) in a Typic Xerofluvent polluted with trace-elements after 24 months at field in 12 plots installed at the surroundings of the Guadiamar Green Corridor (37° 23' 7.152"N, 6° 13' 43.175"; Southwest Spain). Specifically, for this study the effects of biochar amendment on soil physical properties (pH, water holding capacity-WHC, moisture, etc), elemental composition, total SOM, the content of oxidizable SOM as well as the content and composition of humic acids (HAs) have been assessed.</p><p>Biochar application caused an increase in soil pH (around 0.4 units), soil moisture (from 6-7% to 10-18 %) and WHC. In addition, the total organic carbon and HAs content increased slightly. Preliminary results show that biochar could become part of the humified SOM in a shorter time than initially expected. Nevertheless, the spectroscopic analyses (FT-IR and <sup>13</sup>C NMR spectroscopy) documented that the qualitative composition of soil HAs was not altered due to the biochar amendment.</p><p><strong> </strong></p><p><em>References</em>:</p><p>[1] EEA; 2007. CSI 015. Copenhagen, Denmark: European Environmental Agency.</p><p>[2] Madejón, E.; Pérez de Mora, A.; Burgos, P.; Cabrera, F.; 2006. Environ. Pollut. 139, 40-52.</p><p>[3] Campos, P., De la Rosa, J.M., 2020. Sustainability 12, 6025.Uchimiya, M.; Klasson, K.T.; Wartelle, L.H.; Lima, I.M.; 2011. Chemosphere 82, 1438-1447.</p><p>[4] Campos, P., Miller, A.Z., Knicker, H., Costa-Pereira, M.F., Merino, A., De la Rosa, J.M., 2020. Waste Manag. 105, 256-267.</p><p>[5] De la Rosa, J.M.; Rosado, M.; Paneque, M.; Miller, A.Z.; Knicker, H.; 2018. Sci. Tot Environ. 613-614, 969-976.</p><p><em>Acknowledgements</em>: The Spanish Ministry of Economy, Industry and Competitiveness (MINEICO), CSIC and AEI/FEDER are thanked for funding the project CGL2016-76498-R. P. Campos thanks the “Fundación Tatiana Pérez de Guzmán el Bueno” for funding her PhD.</p>

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

INVAR M93

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Low Temperatures ◽  
Bend Strength ◽  
Temperature Performance ◽  
Ni Content ◽  
Precision Alloys ◽  
Ni Alloy

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.

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