Properties of Soils

Over 98% of the soil is made up of only eight major chemical elements, listed in Table 51, in order of decreasing abxmdance. The 90-odd others make up the remaining 2% many occur in the soil as secondary or minor elements, while a large number of still others are present in only very low, often trace, concentrations. Thus all soils contain main, minor, and trace elements combined into chemical compounds and aggregated into complex parhcles of varying shape, size, and chemical composition (see Textbox 8). 

The size, and particularly the size distribution of the particles (or PSD, as particle size distribution is often abbreviated), which is closely related to the texture of the soil, is an important characteristic that determines many of the 

The pH of Sotts. The pH of soils (see Textbox 48) varies widely with location and climate the local climate of a region usually provides a clue as to the pH of the soil. In high-rainfall regions, for example, soils are generally acid. Alkaline soils, in contrast, typically occur in low-rainfall areas the actual value of the pH varies over a wide range, from below 5 in very acid 

TABLE 52 Soil Particle Size and Soil Types 

With very few exceptions, naturaiiy occurring acids and aikaiies are weak. Aii acids known in antiquity were of organic origin some occur in fruits, especiaiiy in unripe fruitjuices. Most ancient aikaiies were derived from the ash of piants such as bariiia, Salsola soda and Salsola kali (Russian thistie), and keip. 

---

Easily observed physical properties of soils often are useful indexes of behavior. These index properties include texture and appearance, specific weight, moisture content, consistency, permeability, compressibility, and shearing strength [37,38]. 

Ralston, C.W. Hatchell, G.E. Effects of prescribed burning on physical properties of soil Prescribed Burning Symp. Proc. USDA For. Serv. Southeast For. Exp. Sta. Asheville, NC, 1971 pp 68-85. 

Brady, N. C. and Weil, R. (1999). "The Nature and Properties of Soils," 12th edn. Prentice Hall. 

Pedro, G. (1982). The conditions of formation of secondary constituents. In "Constituents and Properties of Soils" (M. Bonneau and B. Souchier, eds), pp. 63-81. Academic Press, New York. 

Irrigation has been practiced from the ancient time it is only in the twentieth century that the importance of the irrigation water quality was recognized [7]. The use of saline water may result in the reduction of crop yields. A high sodicity of water for irrigation may cause the deterioration in the physical properties of soils... 

Table I. Properties of Soils Used in Mobility Studies with the Chlorodioxins...

Handbook of Soil Conditioners Substances That Enhance the Physical Properties of Soil, edited by Arthur Wallace and Richard E. Terry Environmental Chemistry of Selenium, edited by William T. Frankenberger, Jr., and Richard A. Engberg... 

Direct shear test of soils under consolidated drained conditions Consolidated-undrained triaxial compression test on cohesive soils One-dimensional consolidation properties of soils One-dimensional consolidation properties of soils using controlled-strain loading... 

Alternative final cover systems, such as the innovative evapotranspiration (ET) cover systems, are increasingly being considered for use at waste disposal sites, including municipal solid waste (MSW) and hazardous waste landfills when equivalent performance to conventional final cover systems can be demonstrated. Unlike conventional cover system designs that use materials with low hydraulic permeability (barrier layers) to minimize the downward migration of water from the cover to the waste (percolation), ET cover systems use water balance components to minimize percolation. These cover systems rely on the properties of soil to store water until it is either transpired through vegetation or evaporated from the soil surface. 

Because of the water-holding properties of soils and the fact that most precipitation returns to the atmosphere via ET, it is possible to devise a landfill cover to meet remediation requirements, and yet contain no barrier layer. The ET cover consists of a layer of soil covered by native grasses it contains no barrier or impermeable layers. The ET cover uses two natural processes to control infiltration (1) soil provides a water reservoir and (2) natural evaporation from the soil plus plant transpiration (ET) empties the soil water reservoir.32-38 The ET cover is an inexpensive, practical, and easily maintained biological system that will remain effective during extended periods of time—perhaps centuries—at low cost. 

Soils altered in the past by human habitation are not difficult to find. Farmers in many regions of North America, for example, noted that the soil of old Indian villages was more productive than adjacent soils. The unique properties of soils from ancient inhabited places have frequently been put to use in many places in the world farmers in the Ashdod area in Israel and El Phosfat in Egypt, for example, used the soil that they excavated from ancient archaeological sites to fertilize the land they cultivated (Wright 1986). 

Brady NC, Weil RR. The Nature and Properties of Soil. 14lh ed. Upper Saddle River, New Jersey Prentice-Hall 2008. 975 p. 

Watanabe A, Kimura M. Influence of chemical properties of soils on methane emission from rice paddies. Comm. Soil Sci. Plant Anal. 1999 30 2449-2463. 

In addition, the removal of organic matter and Fe oxides from soils and sediments is common practice as a pretreatment for soils prior to physical, chemical and biological analyses. The effects of the removal of these components on physicochemical and surface chemical properties of soils will be discussed as well. 

In summary, the removal of organic matter and Fe oxides significantly changes the physicochemical and surface chemical properties of soils. Thus, this pretreatment affects the overall reactivity of heavy metals in soils. The removal of organic matter and Fe oxides may either increase or decrease heavy metal adsorption. The mechanisms responsible for the changes in metal adsorption in soils with the removal of organic matter and Fe oxides include increases in pH, surface area, CEC and electrostatic attraction, decreases in the ZPC, shifts of positive zeta potentials toward... 

Metal oxides have a significant role in influencing physical, chemical, and biological properties of soils. They may exist as ciystalline minerals, as short-range ordered (SRO) mineral colloids, or as surface coatings on clay minerals and organic matter. Organic compounds influence the formation, transformation, and surface properties of these metal oxides. The SRO A1... 

Tejada M, Garcia C, Gonzalez JL, Hernandez MT (2006) Use of organic amendment as a strategy for saline soil remediation Influence on the physical, chemical and biological properties of soil. Soil Biol Biochem 38 1413-1421... 

Guisquiani PL, Marucchini C, Businelli M (1988) Chemical properties of soils amended with compost of urban waste. Plant Soil 109 73-78... 

These properties of soils in Steppe ecosystems are favorable to the formation of uppermost humus barrier, where the accumulation of almost all the chemical species occur. The concentration of chemical elements is slightly decreasing downward in soil profile, in parallel with decreasing soil humus content (Figure 2). 

The characteristic property of soils from Mangrove ecosystems is related to the accumulation of mobile water-soluble forms of iron, aluminum and silicon. The downward increase in soil profile was shown for iron and aluminum and an opposite trend for silicon (Table 14). 

These values are significantly different from those that have been earlier calculated by RAIN-ASIA model (World Bank, 1994). These differences might be related to the much more detailed and comprehensive national data sets on geological, soil, climate (precipitation, temperature, evapotranspiration, runoff, etc.) and vegetation mapping, physico-chemical properties of soils and geological rocks. This allows the authors to calculate more precise values of all constituents used for maximum sulfur critical load calculation and mapping. 

The series is indeed being well received, and is growing prosperously. New volumes, on fractal properties of soil particles and physical techniques for micro/nanoparticle characterisation respectively, are in an early stage of preparation. As with all books in the series, these volumes will present critical reviews that reflect the current state of the art and provide guidelines for future research in the field. 

Brady, N.C. and Buckman H.O. (1990). The Nature and Property of Soils. Prentice Hall, Upper Saddle River, New Jersey, 10th edn. 

Fujitake N, Kusumoto A, Tsukamoto M, Kawahigashi M, Suzuki T, Otsuka H. Properties of soil humic substances in fractions obtained by sequential extraction with pyrophosphate solutions at different pHs I. Yield and particle size distribution. Soil Sci. Plant Nutr. 1998 44 253-260. 

---