Soil Reserves of Potassium: Release and Availability to Lolium perenne in Relation to Clay Minerals in Six Cropland Soils from Eastern China

2017 ◽  
Vol 28 (5) ◽  
pp. 1696-1703 ◽  
Author(s):  
Ting Li ◽  
Huoyan Wang ◽  
Xiaoqin Chen ◽  
Jianmin Zhou
Keyword(s):  
Clay Minerals ◽  
Lolium Perenne ◽  
Eastern China ◽  
Potassium Release

The solubility of potassium from soil illites. II. Mechanisms of potassium release

Soil Research ◽  
1964 ◽  
Vol 2 (1) ◽  
pp. 67 ◽  
Author(s):  
BM Tucker
Keyword(s):  
Clay Minerals ◽  
Silicic Acid ◽  
Calcium Ions ◽  
Hydrogen Ion ◽  
Displacement Reaction ◽  
Potassium Release ◽  
Ph Values ◽  
Soil Clays ◽  
Mineral Structure

The release of potassium from four soil clays containing illites of different degrees of degradation was found to be independent of the solution of silicic acid or aluminium from the clay minerals. The lattice potassium is released into solution by a displacement reaction. The displacement of potassium by calcium ions is dependent on the prior release of one lattice potassium by one hydrogen ion, presumably because the entry of the hydrogen ion makes the potassium at neighbouring sites in the lattice accessible to other cations. The reaction may be written as 7Ks+ + H+ + 3Ca2+ 7K+ + 3CaS2+, where the subscript S refers to the solid (clay) phase. At pH values above pH 11, potassium is released by breakdown of the mineral structure by the action of hydroxyl ions.

scholarly journals Chemical compaction of deep buried mudstone and its influence on pressure prediction

2020 ◽  
Vol 600 (1) ◽  
pp. 012012
Author(s):  
Li Chao ◽  
Luo Xiaorong ◽  
Zhang Likuan ◽  
Lei Yuhong ◽  
Chen Ming ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Clay Minerals ◽  
Eastern China ◽  
Bohai Bay ◽  
Dongying Depression ◽  
Pore Pressure Prediction ◽  
Shahejie Formation ◽  
Vertical Effective Stress ◽  
The Impact ◽  
Transformation Of Clay Minerals

Abstract The chemical compaction of mudstones which is dominated by the transformation of clay minerals leads to significant changes in the mineral composition and microstructure of mudstone during process of deep burial. In particular, the transformation of smectite to illite in mudstones results in noticeable impact on the pore pressure formation and the overpressure logging responses. At present, the study about the pressurization mechanism of chemical compaction and the impact on overpressure logging responses is really weak, which made it hard to pore pressure identification and pressure prediction for deep buried formations. Taking the Paleogene Shahejie Formation in the Dongying depression of the Bohai Bay Basin in eastern China as typical case, this paper analyses the characteristics of clay mineral transformation of the Shahejie Formation in the Dongying depression, the logging responses of overpressures, and the influence of chemical compaction on the prediction of pore pressure. The results showed that the chemical compaction of mudstones changes the relationship between the petrophysical properties of mudstone and vertical effective stress and the logging responses of overpressure. The typical characteristic of chemical compaction manifested as density increase continuous with the depth. The normal compaction trends of the different compaction stages are the basis for overpressure mechanisms identification and pore pressure prediction. The depth of the rapid transformation of clay minerals has a good consistency with the top of overpressure zone (2000–2800 m) in Dongying depression, which indicates that the overpressure and its logging responses may be related to the chemical compaction of mudstones. The measured pressure in intervals deeper than 3000 m is closer to the predicted pressure based on the normal compaction trend of chemical compaction.

Hydrated form of some clay minerals observed using a film sealed environmental cell

1978 ◽  
Vol 36 (1) ◽  
pp. 72-73
Author(s):  
N. Kohyama ◽  
K. Fukushima ◽  
A. Fukami
Keyword(s):  
Clay Minerals ◽  
Morphological Changes ◽  
Carbon Film ◽  
Electron Microscopic Observation ◽  
Adsorbed Water ◽  
Electron Microscopic ◽  
Hydrated Form ◽  
Thin Carbon ◽  
Environmental Cell ◽  
Thin Carbon Film

Since the interlayer or adsorbed water of some clay minerals are quite easily dehydrated in dried air, in vacuum, or at moderate temperatures even in the atmosphere, the hydrated forms have not been observed by a conventional electron microscope(TEM). Recently, specific specimen chambers, “environmental cells(E.C.),” have been developed and confirmed to be effective for electron microscopic observation of wet specimen without dehydration. we observed hydrated forms of some clay minerals and their morphological changes by dehydration using a TEM equipped with an E.C..The E.C., equipped with a single hole copper-microgrid sealed by thin carbon-film, attaches to a TEM(JEM 7A) with an accelerating voltage 100KV and both gas pressure (from 760 Torr to vacuum) and relative humidity can be controlled. The samples collected from various localities in Japan were; tubular halloysite (l0Å) from Gumma Prefecture, sperical halloysite (l0Å) from Tochigi Pref., and intermediate halloysite containing both tubular and spherical types from Fukushima Pref..

Techniques for preparing the Lolium perenne coleorhiza for scanning electron microscope evaluation

1992 ◽  
Vol 50 (1) ◽  
pp. 766-767
Author(s):  
Susan B.G. Debaene ◽  
John S. Gardner ◽  
Phil S. Allen
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Lolium Perenne ◽  
Morphological Study ◽  
Root Hairs ◽  
Inner Pressure ◽  
Water Potentials ◽  
Radicle Emergence ◽  
Standard Fixation ◽  
Scanning Electron

The coleorhiza is a nonvascular sheath that encloses the embryonic radicle in Poaceae, and is generally the first tissue to emerge during germination. Delicate hairlike extensions develop from some coleorhiza cells prior to radicle emergence. Similar to root hairs, coleorhiza hairs are extremely sensitive to desiccation and are damaged by exposure to negative water potentials. The coleorhiza of Lolium perenne is somewhat spherical when first visible, after which a knob forms at a right angle to the caryopsis due to inner pressure from the elongating radicle. This knob increases in length until the radicle finally punctures the coleorhiza. Standard fixation procedures cause severe desiccation of coleorhiza cells and hairs, making morphological study of the coleorhiza difficult. This study was conducted to determine a more successful process for coleorhiza preservation.

Colloidal systems in soils

1994 ◽  
Vol 52 ◽  
pp. 64-65
Author(s):  
J. Thieme ◽  
J. Niemeyer ◽  
P. Guttman
Keyword(s):  
Clay Minerals ◽  
Polymeric Materials ◽  
Spatial Arrangement ◽  
High Specific Surface Area ◽  
Turnover Rates ◽  
Colloidal Systems ◽  
Chemical Conditions ◽  
Aggregation Phenomena ◽  
Iron And Manganese ◽  
Soil Colloids

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

PAH contamination of the grass Lolium perenne exposed to vehicular traffic

Agronomie ◽  
2004 ◽  
Vol 24 (8) ◽  
pp. 503-506 ◽  
Author(s):  
Cécile Crépineau-Ducoulombier ◽  
Abdourahamane Tankari Dan-Badjo ◽  
Guido Rychen
Keyword(s):  
Lolium Perenne ◽  
Vehicular Traffic
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