Soil Science Society of America Journal

doi: 10.2136/sssaj1962.03615995002600050001xpmid: N/A

doi: 10.2136/sssaj1962.03615995002600050002xpmid: N/A

Vomocil, J. A.; Waldron, L. J.

doi: 10.2136/sssaj1962.03615995002600050003xpmid: N/A

Measurements were made of the applied tensile stress necessary to cause tensile failure of partially saturated samples of uniform sized glass beads.

Cary, J. W.; Taylor, S. A.

doi: 10.2136/sssaj1962.03615995002600050004xpmid: N/A

The theory of thermodynamics of irreversible processes and the Onsager reciprocal relation were tested for the case of thermally induced water vapor diffusion through air and through moist soil in the temperature range of 15° to 45°C. The general rate equations for heat and mass flow were transformed into simple relations giving the flux as a function of temperature.

Cary, J. W.; Taylor, S. A.

doi: 10.2136/sssaj1962.03615995002600050005xpmid: N/A

The basic rate equation developed from Onsager's theory and thermodynamics of irreversible processes was modified for liquid phase moisture diffusion. This was done by accounting for the thermal dependence of the phenomenological coefficients with Eyring's theory of rate processes.

Kunze, Raymond J.; Kirkham, Don

doi: 10.2136/sssaj1962.03615995002600050006xpmid: N/A

Miller and Elrick's method of computing capillary conductivity for nonnegligible membrane impedance has been modified to reduce the amount of calculation required for converting pressure plate outflow data to capillary conductivities. Plate impedance need not be measured and variable contact impedance is accounted for. The method is most practical if accurate time and outflow measurements can be made shortly after making a small step change in pressure. An apparatus is described to make such measurements. To minimize diffusivity changes associated with moisture outflow, only the initial portion of the outflow data resulting from the step change in pressure is used. The relationship between capillary conductivity and moisture content is shown for two soils.

Conaway, Andrew W.; Strickling, Edward

doi: 10.2136/sssaj1962.03615995002600050007xpmid: N/A

Aggregate stability was determined on samples taken from plots under 10 cropping systems on a Beltsville silt loam and on samples taken from selected soil types in Maryland, North Carolina, South Dakota, Texas, and Wisconsin. Complete aggregate and mechanical analysis curves were determined on the 2.0‐ to 4.76‐mm. fraction from each soil sample. The method of Bryant et al. (2) was also used to determine water stability of this fraction.

Taylor, Howard M.

doi: 10.2136/sssaj1962.03615995002600050008xpmid: N/A

A nonporous wax surface crust technique was devised to study seedling emergence of wheat, grain sorghum, and guar. Emergence through crusts with wax penetration numbers ranging from 15 to 80 was evaluated using crust thicknesses of ¼, ½, and 1 inch.

Jurinak, J. J.; Waldron, L. J.; Vomocil, J. A.

doi: 10.2136/sssaj1962.03615995002600050009xpmid: N/A

The importance of adsorptive forces in monodispersed glass bead systems, at high relative pressures, was studied during the adsorption of water and ethylene dibromide by microscopic Pyrex and alkali glass beads, i.e., ideal soil. The analysis of the adsorption data by the Frenkel‐Halsey‐Hill isotherm equation, applicable at high surface coverages, allowed differentiation between capillary condensation and multilayer adsorption. Polymolecular adsorption accounted for all adsorption of water up to P/P0 = 0.98 with no indication of condensation. The type of glass had a marked effect on the nature of water interaction. Evidence is presented which indicates that both ethylene dibromide and ethyl alcohol (data from literature) exhibit phase transitions in the multilayer region of adsorption.

Reed, M. G.; Scott, A. D.

doi: 10.2136/sssaj1962.03615995002600050010xpmid: N/A

A mathematical expression that describes the release of interlayer K from mica particles in NaCl‐NaTPB solutions was derived. The mica particles were assumed to be circular discs and the rate determining process for the release of K was considered to be the simultaneous diffusion of K and Na within the particle. Therefore, this derivation involved the solution of a two‐dimensional radial diffusion problem in which K diffuses from a receding weathering front to the periphery of the particle.