Saline soil characterization

Cilenti, A., Provenzano, M. R., and Senesi, N. (2005). Characterization of dissolved organic matter from saline soils by fluorescence spectroscopy. Environ. Chem. Lett. 3(2), 53-56. 

Soils are said to be sodic if they contain an excess of sodium. According to their content of salts and sodium, soils are grouped in saline-nonsodic, saline-sodic, nonsaline-sodic, and normal soils. In arid regions, soils rich in sodium are widely distributed due to salt accumulation as sodium chloride and sodium sulfate. The salt-affected soils are chemically characterized by the specific conductivity (mS-cm ) [S = Siemens] of the saturation extract and the saturation of the CEC (%) with sodium. The major cationic constituents of the soluble salts in saline soils are sodium, calcium, and magnesium. Precipitation of Ca and Mg as carbonates effects an increase in the proportion... 

The basement complex for the Patagonian desert and arid northeastern Brazil is formed by metamorphosed Precambrian rocks. Landscapes are characterized by level erosion surfaces of different ages. The landscape is dissected by a large number of valleys. Large depressions are filled with marine and continental beds of sedimentary rocks. Rocks in the Andean system, that stretches the entire length of the west side of the continent, vary greatly. Many depressions are filled with sediments. In addition, many active volcanoes are responsible for periodic lava flows and the deposition of volcanic ash. East of the Andes, the land surface is level and slopes towards the Atlantic Ocean. Broad depressions contain saline or sodic soils. 

Workers at the U.S. Salinity Laboratory proposed the sodium adsorption ratio (SAR) to characterize the sodium status of irrigation waters and soil solutions ... 

The analytical methods used for the determination of uranium in environmental samples are basically the standard methods reviewed in brief in Chapter 1. The main differences are in the sample preparation procedures required for the analysis of the variety of environmental samples that include soil of different types, sediments, diverse types of vegetation, water from different sources with a wide range of acidity, salinity, suspended matter, etc. In addition, the environmental samples may include airborne particulate matter, vapors, and gases, as well as special samples involved in the food chain that may affect humans. Einally, the interplay of uranium (and other contaminants) between the environmental compartments—for example, the transfer factors of uranium from soil-to-plant or from vegetation to food products (e.g., free-range grazing cattle) are also part of the media that need to be characterized. 

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