to be quite compatible with the original analytical scheme. Incidentally, El-Attar and Jackson (1973) have observed considerable thermal decomposition at 550~ of Fe-rich layers and/or interlayers in montmorillonitic soils of Nile River alluvium. Additional information that can be deduced from the above procedure is the CEC and K § -fixation capacity of the amorphous constituents of the clays pr...

Given a montmorillonitic clay soil at high porosity and saturated by monovalent counterions, we investigate the particle level responses of the clay to different external loadings. As analytical solutions are not possible for complex arrangements of particles, we employ computational micromechanical models (based on the solution of the Poisson-Nernst-Planck equations) using the finite element m...

Soil specific surface area (SA) reflects the quantity and quality of soil mineral organic fractions. For samples that have similar clay types, content or carbon (OC) contents are good predictors SA. However, magnitude OC contribution to SA for different types is unclear, particularly since varies depending on which method probe molecule used measure it. Consequently, we set out (i) quantify tot...

In order to accurately model soil reclamation with concentrated electrolytes such as CaCl2 or sea water, it must be determined if there is an effect of salinity on the Na-Ca exchange selectivity. A new procedure for determining Na-Ca selectivity in calcareous and gypsiferous soils was used to study the effects of ionic strength and mineralogy on Na-Ca exchange. Four specimen clay minerals and t...

The roles of NH.-N diffusion, NH.-N oxidation, NO3-N diffusion, and NO3-N reduction in controlling N loss from continuously flooded soil were evaluated in independent experiments. Applied NH,-N moved from zones of high NH4-N concentration to the zones of low NH4-N concentration. The average diffusion coefficient (D) for NH.-N in flooded soil ranged from 0.059 to 0.216 cm" day for different soil...

Clay mineral studies in the U.S.S.R., mainly since 1960, are summarized. Electron diffraction techniques especially have been developed and used extensively. Methods have been developed for simultaneous recording of DTA curves and other properties. Polytypism of phyllosilicates has been studied intensively by Zvyagin and others. Mucfi new information on the structure and morphology of halloysit...

Given a montmorillonite clay at high porosity and saturated by monovalent counterions, the particle level responses of the clay to different external loadings are investigated. As analytical solutions are not possible for complex arrangements of particles, computational micromechanical models are employed (based on solution of the Poisson-Nernst-Planck equations) using the finite element method...