scholarly journals Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tope O. Bolanle-Ojo ◽  
Abiodun D. Joshua ◽  
Opeyemi A. Agbo-Adediran ◽  
Ademola S. Ogundana ◽  
Kayode A. Aiyeyika ◽  
...  

Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+were carried out on three surface (0–30 cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27 cmolc kg−1) but relatively high base saturations (≫50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. TheKeqvalues obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions.

2005 ◽  
Vol 62 (6) ◽  
pp. 552-558 ◽  
Author(s):  
Adriel Ferreira da Fonseca ◽  
Luís Reynaldo Ferracciú Alleoni ◽  
Adolpho José Melfi ◽  
Célia Regina Montes

The addition of Na-rich anthropogenic residues to tropical soils has stimulated the scientific community to study the role of sodium in both the soil solution and the exchange complex. In this study, several different methods were used to calculate the concentration of exchangeable and soluble cations and this data was then used to establish correlations between the level of these cations and both the accumulation of various elements and the dry weight of maize grown in a greenhouse under different conditions. In the closed environments of the pots, the most suitable method for calculating the effective cation exchange capacity (ECEC) was the cation exchange capacity calculated by cations removed with barium chloride solution (CEC S). Then again, the actual cation exchange capacity (CEC A) should be measured by using Mg adsorption to prevent ionic force from influencing electric charges. A strong positive correlation was obtained between the concentrations of Na in the 1:2 soil:water extracts and the accumulation of Na in the maize plants, indicating saline or double acid extractors are not needed when monitoring the Na concentration only.


Author(s):  
Antonio Carlos Saraiva da Costa ◽  
Ivan Granemann de Souza ◽  
Leila Cristina Canton ◽  
Luciano Grillo Gil ◽  
Rodolfo Figueiredo

1969 ◽  
Vol 36 (2) ◽  
pp. 155-160
Author(s):  
M. A. Lugo López ◽  
F. Abruña ◽  
J. Roldán

The quantity of limestone required to bring the pH of various acid Puerto Rican soils to 6.5 was investigated and found to vary from several hundred to several thousands pounds per acre. To investigate the relation of clay-mineral type, clay content, cation-exchange capacity, organic-matter content, and pH to lime requirement, these properties were determined for several soils. A highly significant regression of lime requirement on pH was obtained which can be expressed by the equation: Y = 18.39 — 3.196 X, where Y is the lime requirement and X is the pH value. Multiple regressions including other factors did not significantly increase the variability which could be explained on terms of the first regression. Further analysis were made by arranging the data according to the predominant clay mineral. For kaolinitic soils highly significant correlations were obtained between lime requirement and either pH or cation exchange capacity. The regressions were: (a) Y = 15.26 — 2.632 pH, and (b) Y = 3.048 + 0.5774 (cation-exchange capacity), where Y is the lime requirement. A regression of lime requirement on both factors did not significantly increase the variability explained by the second equation. No significant regressions were obtained for beidellitic soils.


1962 ◽  
Vol 10 (3) ◽  
pp. 194-210
Author(s):  
P. Delver

Data on soil texture, lime, gypsum, cation-exchange capacity, salinity, alkalinity, hydraulic conductivity and their interrelations and variations are discussed. An equation expresses the relationship between exchangeable Na and cations soluble in 1: 1 extracts. Special attention is paid to whether alkalization and structure deterioration will occur during reclamation. Gypsum contents seem to be adequate for replacement of Na by Ca during leaching but temporary decrease in permeability in early stages of leaching may occur due to retarded exchange reactions caused by the nature of the clay minerals. (Abstract retrieved from CAB Abstracts by CABI’s permission)


Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 177 ◽  
Author(s):  
Z Hochman ◽  
DC Edmeades ◽  
E White

Eleven acidic soils from northern N.S.W., having a wide range of values for ECEC, A1 and soil organic carbon (%C), were treated in the field with five rates of lime. The relationships between soil pH and the effective cation exchange capacity (ECEC), and between pH and exchangeable aluminium (Al), were investigated for the top 10 cm of these soils. Increases in the total exchangeable cations (TEC) calculated as ECEC-Al, were shown to be madelup almost entirely by increases in exchangeable calcium. There were no consistent changes in the amount of exchangeable magnesium, potassium or sodium due to liming these acidic soils. Formulae used to predict changes in A1 and ECEC with pH in the 'Lime-it' model were tested and modified on the 11 soils from northern N.S.W. A strong linear relationship was observed in each soil between Al and pH (transformed to hydrogen ion concentration x 103). The slope of this relationship (SALs) can be predicted from the pH and A1 values of unlimed soils. Strong linear relationships were also observed between pH and TEC, for each of the 11 soils. The SL, (the slope of the linear relationship TEC/pH for any soil 's') was shown by multiple regression analysis to be a function of TECi/pHi (where TECi is the sum of exchangeable cations of unlimed soil 's'; and pHi is the pH value of unlimed soil 's'), %C of the unlimed soil, and SALs. By using the measured values of pH, ECEC, Al and %C of unlimed soils, the values of Al, and TEB can be predicted for any pH value that may be measured (or predicted) after liming. The predictive relationships developed on N.S.W. soils were tested against independent data from New Zealand. The results confirmed the Al/pH predictions (R2 = 0.955), while the TEC/pH predictions were less well matched (R2= 0.62) possibly due to unusual clay mineralogy or organic matter fractions of 3 of the 18 soils tested.


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