Modification of soil

The temporal decrease in emitted mass flux in the case of particles with a wide size distribution has been shown by a few experimental studies [3-5]. These authors assume that the temporal decrease in emitted flux is due to modification of soil surface during wind erosion. These experimental studies underline the importance to consider the temporal evolution of the emitted mass flux in order to accurately estimate particles emissions with a wide size distribution. 

Pagliai, H., Guidi, G., and Petruzzelli, G. (1979). Effect of molecular weight on dextran-soil interactions. In Modifications of Soil Structure, Emerson, W. W., Bond, A. D., and Dexter, A. R., eds., John Wiley Sons, New York, pp. 175-180. 

Adani, F, Genevini, P., Ricca, G.,Tambone, F, and Montoneri, E. (2007), Modification of soil humic matter after 4 years of compost application. Waste Manage. 27, 319-324. 

The mining of massive sulfur deposits and the exposure of the element to air and water permits the development of populations of sulfur-oxidizing bacteria, with concomitant formation of acidity and sulfate ions. The occurrence of T. thiooxidans and T. thioparus in the Rozdol deposit in Russia has been described by Karavaiko (1959 1961). Similar events can occur during the industrial uss e of elemental sulfur and the amenability of sulfur to bacterial oxidation has been widely exploited agriculturally for modification of soil acidity, supply of sulfate ion and for in situ solubilisation of rock phosphate (Starkey, 1950 Gleen and Quastel, 1953 Vitolins and Swaby, 1969). While most attention has been focussed on chemolitho-trophic thiobacilli, such as T. thiooxidans and T. thioparus, an ability to oxidise elemental sulfur has been shown to be possessed by a number of heterotrophs such as the 35 species of Streptomyces examined by Yagi et al. (1971) and Arthrobacter (Ehrlich, 1962). 

The modification of soil and rock properties by filling voids and cracks dates back two centuries. The materials used to fill the voids and cracks are termed grouts. Grouts run the gamut from low viscosity liquids to thick mixtures of solids and water. Grouts which consist of a flowable mixture of solids and water are called suspended solids grouts. The most common by far is Portland cement and its many variations. 

J. P. Quirk, Some physico-chemical aspects of soil structural stability—A review, in Modification of Soil Structure (W. W. Emerson, R. D. Bond, and A. R. Dexter, eds.) Wiley, Chichester, U.K., 1978. Y. Chen and A. Banin, Scanning electron microscope (SEM) observations of soil structure changes induced by sodium-calcium exchange in relation to hydraulic conductivity, Soil Sci. 120 428 (1975). Y. Chen, J. Tarchitzky, J. Brouwer, J. Morin, and A. Banin, Scanning electron microscope observations on soil crusts and their formation, Soil Sci. 130 49 (1980). 

W. W. Emerson, R. D. Bond, and A. R. Dexter, Modification of Soil Structure. Wiley, Chichester, U.K., 1978. The first five chapters of this symposium publication provide details on many aspects of the surface chemical features of soil colloidal stability. 

WAKSMAN S.A. and WOODRUFF H.B. 1940. Survival of bacteria added to soil and the resultant modification of soil population. Soil Science, 50, 421-427. 

PAGLIAI M., GUIDO G. and PETRUZZELLI G. 1978. Effect of molecular weight on dextran - soil interactions. Chapter 21 in Modification of Soil Structure. Eds,Emerson W.W., Bond R.D. and Dexter A.R. 

Chemical modification of the wax can improve smear resistance (5). Sihcones, which do not harm furniture finishes (6), are incorporated as film-forming ingredients in furniture pohshes. The lubricant properties of sihcones improve ease of apphcation of the pohsh and removal of insoluble soil particles. In addition, sihcones make dry films easier to buff and more water-repeUent, and provide depth of gloss, ie, abihty to reflect a coherent image as a result of a high refractive index (7). Wax-free pohshes, which have sihcones as the only film former, can be formulated to dehver smear resistance (8). Another type of film former commonly used in oil-base furniture pohshes is a mineral or vegetable oil, eg, linseed oil. 

To obtain reproducible antibiotic production by fermentation, it is necessary to obtain a pure culture of the producing organism. Pure cultures are isolated from mixed soil sample populations by various streaking and isolation techniques on nutrient media. Once a pure culture has been found that produces a new antibiotic typically on a mg/L scale, improvement in antibiotic yield is accompHshed by modification of the fermentation medium or strain selection and mutation of the producing organism. Production of g/L quantities may take years to accomplish. 

Plants may be affected by indirect modifications of the environment. Soil acidification, for example, can cause the leaching of nutrients, and the release of toxic aluminum. These effects may operate together to produce nutrient deficiencies or imbalances to plants. High soil concentrations of aluminum may prevent uptake and utilization of nutrients by plants.Increased availability of aluminum in soils has been implicated as a cause of forest declines in both Europe and the United States, possibly through the toxic effects on small feeder roots 14),... 

Xenobiotics exist not only in the free state but also in association with organic and mineral components of particles in the water mass, and the soil and sediment phases. This association is a central determinant of the persistence of xenobiotics in the environment, since the extent to which the reactions are reversible is generally unknown. Such residues may therefore be inaccessible to microbial attack and apparently persistent. This is a critical factor in determining the effectiveness of bioremediation (Harkness et al. 1993). Although the most persuasive evidence for the significance of reduced bioavailability comes from data on the persistence of agrochemicals in terrestrial systems (Calderbank 1989), the principles can be translated with modification to aquatic and sediment phases that contain organic matter that resembles structurally that of soils. 

Modifiers Modification of the rhizosphere soil with (e.g., protons, reductants)... 

Protection against competition Modification of rhizosphere. soil with phytoactive compounds (e.g.. allelochemi-cals)... 

ATPase and specific modification of root cell membrane permeability directly mediated by low-molecular-weight (<5000 Da) fulvic acid-like compounds deriving from native soil organic matter (54-56) (see also Chap. 5). 

Agricultural interests have amended existing soil properties to improve productivity their experience demonstrates the power of knowledge of soil properties and the ability to control them.14 A primary benefit of these amendment efforts was improvement in soil-water-holding capacity and increased rate of water removal from all soil layers by plants. The benefits of soil modification remain effective for decades. There is opportunity for similar improvements in soil during ET landfill cover design and construction. Control of ET cover soil properties has potential to enhance cover performance and should add little to construction cost. 

FIGURE 48 A soil profile. Many of the characteristics of soils vary with depth. A convenient way of representing its varying characteristics is by dividing the soil into layers, usually referred to as horizons, identified by letter symbols. The surface layer, which is known as the A horizon, is generally rich in organic matter. Next come the B and C horizons, each of which may have compositional characteristics and modifications. The deepest soil horizon (R) is solid rock. The illustration identifies clearly defined horizons, although in most soils the horizons are not as clear and in some they may be very diffuse. 

Grossman R.B., Millet J.C. Carbonate removal from soils by a modification of the acetate buffer method. Soil Science Soc Am Proc 1961 25 325-326. 

Minimize the contact between living area and subjacent soil. Buildings with slab on grade or ventilated crawl space require less modification of the standard design than houses with basements. If basements cannot be avoided on radon dangerous soil, it is recommended to keep the basement separated from the living space by normally closed doors and if possible, install exhaust ventilation from the basement. 

Brixie JM, Boyd SA (1994) Treatment of contaminated soils with organoclays to reduce leachable pentachlorophenol. J Environ Qual 23 1283-1290 Brown MJ, Burris DR (1996) Enhanced organic contaminant sorption on soil treated with cationic surfactants. Ground Water 34 734-744 Burris DR, Antworth CP (1992) In situ modification of an aquifer material by a cationic surfactant to enhance retardation of organic contaminants. J Contam Hydrol 10 325-337... 

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