Factors in soils

Pesticides, especially OCPs, remain a constantly active factor in soil contamination for many years. 

Figure 2.2. F.lemental enrichment factors in soils, plotted on a log scale against the ionic potential of the elements...

Robert M, Berthelin J (1986) Role of biological and biochemical factors in soil mineral weathering. In Huang PM, Schnitzer M (eds) Interactions of soil minerals with natural organics and microbes. Soil Sci Soc Am, Madison WI USA, pp 453 195... 

Table 1 Average elemental concentrations in the earth s crust and in soil, and the enrichment factor in soil...

Intact soil life an important factor in soil fertility... 

Jenny H. J. (1941) Factors in Soil Formation. McGraw-Hill, New York. 

Retallack G. J. (1994c) The environmental factor approach to the interpretation of paleosols. In Factors in Soil Formation A Fiftieth Anniversary Retrospective, Soil Sci. Soc. Am. Spec. Publ. (eds. R. Amundson, J. Harden, and... 

Robert, M., and Berthelin, J. (1986). Role of biological and biochemical factors in soil mineral weathering. In Interactions of Soil Minerals with Natural Organics and Microbes, ed. Huang, P. M., and Schnitzer, M., Soil Science Society of America, Madison, WI, 453-495. 

Figure 8.10. The boundary between structural stability (flocculation zone) and instability (dispersion zone) as influenced by chemical factors in soils.

Slatyer, R. O., and Mcllroy, I. C. (1961). Practical Microclimatology with Special Reference to the Water Factor in Soil-Plant-.Atmosphere Relations. UNESCO. 

Glaciers have also been major factors in soil formation, as,for example, in the soils of the Corn Belt. Soils and rocks that at one time were in southern Canada and the northern portion of the United States were scooped out, pulverized and mixed by the moving ice and deposited further south when the ice melted. The scouring and scooping action was responsible for the formation of the Great Lakes. 

Animal life in and on the soil, wliich is of course dependent upon plant life, is also a considerable factor in soil formation, as is brought out in Chapter 4. 

Bacteria are of two general types. These are heterotrophic that depend on organic compounds, synthesized by chlorophyll-containing plants, for their nutrition and autotrophic that are either able to oxidize certain inorganic compounds or which contain chlorophyll and can utilize sunlight as their energy source. The photosynthetic bacteria are not an important factor in soil and hence need not be considered in the present discussion. 

Effective dose fi-om y-emitters distributed in soil for depth d > 0 is less than assessed by the coefficient Ky due to absorption in the soil layer above the radionuclides. The attenuation coefficient and build-up factor in soil depends primarily on the y energy, depth of distribution, soil composition, and density. 

Table 6.37 indicates that the absence or presence of significantly deteriorated exterior LBP is a major factor in soil Pb concentration. At the 400 ppm or higher bare soil hazard level, the presence of significantly deteriorated exterior LBP increases the Pb concentration almost fourfold (30% versus 8%). The ratios are even more telling at the upper end of the soil Pb thresholds. With significant LBP deterioration, soils with Pb s5,000 ppm are about eightfold higher than test sites without LBP. 

It is well documented that, excessive soil Se concentrations (>3 mg kg" ) occur in areas of North America, China and Ireland, whereas deficient soil Se concentrations (<0.125 mg kg" ) occur in Siberia, New Zealand and the Keshan area of China (Table 6.10 Broadley et al. 2006). The most important factors in soil Se supply to... 

The third class of soils comprises materials that are soluble in neither aqueous nor nonaqueous systems. In both aqueous and nonaqueous systems, these materials are removed by peptization. The amount of literature on either removal or redeposition of insoluble soils in nonaqueous systems is scanty. In dry cleaning, the moisture content of fibers is the prime factor in soil redeposition, as the moisture content may vary from almost completely dry to up to the amount of regain moisture that they normally contain at a relative humidity of 75%. 

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