Defining and Assessing Soil Quality

Visible, near infrared, mid infrared or combined diffuse reflectance spectroscopy for simultaneous assessment of various soil properties

A computationally efficient and rigorous thermodynamic model that predicts the physical state and composition of inorganic atmospheric aerosol is presented. One of the main features of the model is the implementation of mutual deliquescence of multicomponent salt particles, which lowers the deliquescence point of the aerosol phase. The model is used to examine the behavior of four types of tropospheric aerosol (marine, urban, remote continental and non-urban continental), and the results are compared with the predictions of two other models currently in use. The results of all three models were generally in good agreement. Differences were found primarily in the mutual deliquescence humidity regions, where the new model predicted the existence of water, and the other two did not. Differences in the behavior (speciation and water absorbing properties) between the aerosol types are pointed out. The new model also needed considerably less CPU time, and always shows stability and robust convergence.

http://nenes.eas.gatech.edu/Reprints/ISORROPIA_AG.pdf

ISORROPIA: A New Thermodynamic Equilibrium Model for Multiphase Multicomponent Inorganic Aerosols

Field-flow fractionation (FFF) is a family of flexible elution techniques capable of simultaneous separation and measurement. Its sample domain extends across a broad macromolecular-colloidal-particulate continuum from about 1 nanometer to more than 100 micrometers and incorporates both simple and complex macromaterials of biological, biomedical, industrial, and environmental relevance. Complex materials are separated into components to simplify measurement. Component properties measurable by FFF include mass, size, density, charge, diffusivity, and thickness of adsorbed layers. When characterization by these properties is inadequate, other measurement tools can be readily coupled to FFF, either off-line or on-line, by virtue of its flow-elution operation. This article describes the principles and major subtechniques of the FFF family along with application of its measurement and separative capabilities.

https://science.sciencemag.org/content/sci/260/5113/1456.full.pdf

Field-flow fractionation: analysis of macromolecular, colloidal, and particulate materials

The soil organic matter (SOM) pool encompasses plant, animal, and microbial residues in all stages of decay and a diversity of heterogeneous organic substances intimately associated with inorganic soil components. The soil microbiota and fine roots may also be considered part of the SOM pool. The turnover of the different SOM components varies continuously due to the complex interaction of biological, chemical, and physical processes in soil. The complexity of SOM and its importance to soil fertility have challenged generations of soil scientists, and numerous studies, of which some date back more than two centuries (see historical review in Kononova, 1961), have covered a vast array of aspects of SOM.

Physical Fractionation of Soil and Organic Matter in Primary Particle Size and Density Separates

Book Chapter describing methods of particle-size analysis for soils. Includes a variety of classification schemes. Standard methods for size distributions using pipet and hydrometer techniques are described. New laser-light scattering and related techniques are discussed. Complete with updated references.

J. W. Bauder

Papers

Particle-size analysis.