Soil alkaline

Residuals Produced The residual produced from the alkali metal dechlorination of soils is reported to be an alkaline soil which requires neutralization. 

Injection of acidic, nutrient-rich water into the highly alkaline soils resulted in "cementing" of the soils. 

Sulphates, silicates, carbonates, colloids and certain organic compounds act as inhibitors if evenly distributed, and sodium silicate has been used as such in certain media. Nitrates tend to promote corrosion, especially in acid soil waters, due to cathodic de-polarisation and to the formation of soluble nitrates. Alkaline soils can cause serious corrosion with the formation of alkali plumbites which decompose to give (red) lead monoxide. Organic acids and carbon dioxide from rotting vegetable matter or manure also have a strong corrosive action. This is probably the explanation of phenol corrosion , which is not caused by phenol, but thought to be caused by decomposition of jute or hessian in applied protective layers. ... 

FIGURE 11.11 The color of these hydrangeas depends on the acidity of the soil in which they are growing acid soil results in blue flowers, alkaline soil results in pink flowers. 

P. F. White, Soil and plant factors relating to the poor growth of Lupinus species on fine-textured alkaline soils. Aust. J. Agric. Res. 4l il (1990). 

Although iron (Fe) is one of the major soil constituents (0.5-5%), where it is usually present in the oxidized state (Felll), plant availability is severely limited by the low solubility of Fe-(hydr)oxides at pH levels favorable for plant growth. Therefore, plants need special mechanisms foraquiring Fe from sparingly soluble Fe forms to fit the requirements for growth, especially in neutral and alkaline soils, where the availability of Fe is particularly low (151). Mechanisms involved in iron acquisition by plants are also discussed in Chap. 8. 

Actinomycetes are typically most abundant in well drained, circumneu-tral to alkaline soils having abundant organic matter. Water-logging and low pH may reduce populations (37, 38). The numbers of actinomy-cetous organisms isolated from the various soil samples in our study follow this pattern. No clear trend emerged as to a particular edaphic or biotic factor causing an increase in the proportion of inhibitory isolates in a soil sample. 

Grave wax" is a term for a crumbly, waxy substance called adipocere. Adipocere starts to form on the human body about a month after it is buried. It forms easily on the fatty parts of the body such as the cheeks, abdomen, and buttocks. The waxy adipocere protects the body from further decomposition and has even been found on 10O-year-old exhumed corpses. This buildup occurs when a body is buried in highly basic (alkaline) soil. The waxy substance is produced by a chemical reaction between the basic soil and fats in the body in a process called saponification. Saponification is also the process used in the manufacture of soap. 

The pH of Soils. 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... 

Garten and Tucker [49] also studied the soil-to-plant transfer of "Tc. They compared plant uptake of "Tc freshly added to soil with that of "Tc that had aged in the soil for more than a decade. The combination of alkaline soil and freshly added "Tc increased the uptake into radish foliage. The plant/soil concentration ratio was found to be about 40. 

Badawy et al. (2002) reported that in near neutral and alkaline soils, representative alluvial, desertic and calcareous soils of Egypt, lead activity ranged from 10 677 to 10 4 83 M, and was negatively correlated with soil and soil solution pH. It could be predicted in soil solution from the equation log (Pb2+) = 9.9-2pH. In German noncontaminated soil with 2.3% CaC03 and soil pH 8.5, Zn, Cu and Cd are 1.87, 0.66, and 0.20 pM/L in soil solution, respectively (Helal et al., 1996). 

Most primary and secondary minerals found in soil systems are barely soluble in the soil solution. The amount of mass from the bulk phase to hydrated ions in soil solution is negligible compared to the total mass of the solid phase. In arid and semi-arid soils, concentrations of most trace metals in soil solution may be controlled by their carbonates and to some extent by their hydroxides. Other than carbonates, trace elements in arid and semi-arid soils may also occur as sulfate, phosphate or siliceous compounds, or as a minor component adsorbed on the surface of various solid phase components. The solubility of carbonates, sulfates and other common minerals of trace elements in arid and semi-arid soils will be discussed in Chapter 5. Badawy et al. (2002) reported that in near neutral and alkaline soils representative of alluvial, desertic and calcareous soils of Egypt, the measured Pb2+ activities were undersaturated with regard to the solubility of... 

Soil pH affects the transformation of Cr between Cr(III) and Cr(VI) in soils. Since Cr(VI) has greater bioavailability and mobility in soils than Cr(III), which is strongly bound by soil solid matrix (Han and Banin, 1997). Cr(III) can be oxidized by soil manganese oxides into Cr(VI), while Cr(VI) can be reduced by organic matter, Fe(II) and microorganisms in soils. Reduction of Cr(VI) has been found to occur much slower in alkaline soils compared to acid soils (Cary et al., 1997). 

James B.R. Hexavalent chromium solubility and reduction in alkaline soils enriched with chromite ore processing residue. J Environ Qual 1994 23 227-233. 

Soltanpour P.N., Schwab A. P. A new soil test for simultaneous extraction of macro- amd micro-nutrients in alkaline soils. Commun Soil Sci Plant Anal, 1977 8 195-207. 

Nickel normally occurs in the 0 and +2 oxidation states, although other oxidation states are reported (NAS 1975 Nriagu 1980b Higgins 1995). In natural waters Ni2+ is the dominant chemical species in the form of (Ni(H20)6)2+ (WHO 1991 Chau and Kulikovsky-Cordeiro 1995). In alkaline soils, the major components of the soil solution are Ni2+ and Ni(OH)+ in acidic soils, the main solution species are Ni2+, NiS04, and NiHP04 (USPHS 1993). Most atmospheric nickel is suspended onto particulate matter (NRCC 1981). 

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