Soil, cation-exchange capacity

AGRICULTURAL CROPS Sewage sludge (kg/ha) Missouri Maximum addition when soil cation exchange capacity (in meq/100 g) is ... 

Soil cation exchange capacity ranges from less than 5 to more than 15 meq/100 g. 

Soil cation exchangeable capacity is an index used both to evaluate the nutrient and water retention ability of the soil and as an important basis for the amelioration of soil and to apply, rationally, fertiliser. Exchangeable cations absorbed by soil colloid include K+, Na+, Ca2+, Mg2+, Al3+ and H+. K+, Na+, Ca2+ and Mg2+ are exchangeable bases. Al3+ and H+ are exchangeable acids and the sum of these ions is known as the cation exchangeable capacity. Exchangeable Cu2+, Zn2+ and Mn2+ are present at negligible concentrations. 

Helling, S. C., Chesters, G., and Corey, R. B. (1964). Contribution of organic matter and clay to soil cation-exchange capacity as affected by the pH of the saturating solution. Soil Sci. Soc. Am. Proc. 28, 517-520. 

CURTIN D. and SMILLIE G.W. 1978. Estimation of components of soil cation exchange capacity from measurements of specific surface and organic matter. Soil Science Society of America Proceedings, 40, 461-462. 

Cation exchange capacity The ability of a soil or other solid to exchange cations (positive ions such as calcium) with a liquid. 

Methyl parathion is only slightly soluble in pH 7 water (55-60 ppm). This affects its mobility in water and its ability to be leached or solubilized into the water phase of a soil-water system. Factors most likely to affect the adsorption of methyl parathion in soil are organic matter content and cation exchange capacity. In soils of low organic matter (e.g., subsurface soils), calcium concentration, which affects the hardness of the water, may also be important (Reddy and Gambrell 1987). Several studies have shown... 

The main parameters that affect the cost-effectiveness of soil washing include the physicochemical parameters of the soil (grain size distribution, cation exchange capacity, percentage of silt, clay, or organic matter), and the type and concentration of contaminants. 

Soils and vadose zone information, including soil characteristics (type, holding capacity, temperature, biological activity, and engineering properties), soil chemical characteristics (solubility, ion specification, adsorption, leachability, cation exchange capacity, mineral partition coefficient, and chemical and sorptive properties), and vadose zone characteristics (permeability, variability, porosity, moisture content, chemical characteristics, and extent of contamination)... 

Lead may be taken up in edible plants from the soil via the root system, by direct foliar uptake and translocation within the plant, and by surface deposition of particulate matter. The amount of lead in soil that is bioavailable to a vegetable plant depends on factors such as cation exchange capacity, pH, amount of organic matter present, soil moisture content, and the type of amendments added to the soil. Back-... 

The protocol involving NaOAc-HOAc at pH 5 was first proposed and used by Jackson (1958) to remove carbonates from calcareous soils to analyze soil cation exchange characteristics (Grossman and Millet, 1961). Other researchers used HOAc for the extraction of metals from sediments and soils (Nissenbaum, 1972 Mclaren and Crawford, 1973). Tessier et al. (1979) first used the NaOAc-HOAc solution at pH 5 to dissolve the carbonate fraction from sediments. Since then, the NaOAc-HOAc buffer has been widely used as a specific extractant for the carbonate phase in various media (Tessier et al., 1979 Hickey and Kittrick, 1984 Rapin et al., 1986 Mahan et al., 1987 Han et al., 1992 Clevenger, 1990 Banin et al., 1990). Despite its widespread use, this step is not free from difficulties, and further optimization is required in its application. Questions arise with regard to this step in the elemental extraction from noncalcareous soils, the dissolution capacity and dissolution rates imposed by the buffer at various pHs, and the possibility that different carbonate minerals may require different extraction protocols (Grossman and Millet, 1961 Tessier et al., 1979). 

Maryland Soils with low cation exchange capacity vs. high 5 vs. 10 kg Cd/surface ha 11... 

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