Reactive characteristics of certain soils from south Nigeria
1987
Okusami, T.A. | Rust, R.H. | Juo, A.S.R.
Statistical relationships were determined between soil pH, effective cation exchange capacity (ECEC), surface area, and some other soil properties for selected soils of southern Nigeria. The soils were mostly hydromorphic with a pH range of 3.6 to 8.1. Exchange acidity was virtually due to exchangeable Al (r = 0.99). Negative change in pH values indicate a dominant silicate clay mineralogy. The change in pH(pH(KCl- pH(H2O) was correlated with exchangeable Na (r = -0.56), sand content (r = 0.51) and organic C (r = 0.34). Effective cation exchange capacity was low, average of 7.1 cmol(c) kg-1. No exchangeable A1 was found above a soil pH (KCl) of about 4. A derived variable, change in CEC (difference between CEC measured at pH 8.2 and ECEC), was used as a dependent variable to test pH dependence. The variability observed in change in CEC values was found to be related to clay content (r = 0.65), exchangeable K (r = -0.11), and organic C (r = 0.34). A regression analysis with BET-N2 (Brunauer, Emmett, and Teller) specific surface area as the dependent variable showed a strong relationship with clay content (r = 0.96) and change in pH (r = -0.44) in the best regression equation.
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