Department of science Laboratory Technology, Federal Polytechnic, Ilaro, Nigeria.
* Present address: Department of Soil Science and Agricultural Mechanization, University of Agriculture, Abeokuta, Nigeria.
The use of direct colorimetric indophenol blue method of NH4+-N was evaluated for the determination of CEC. Preliminary study shows that the recovery of NH4 + ion is virtually quantitative, accurate and highly reproducible. Forty soil samples from different ecological zones of South-Western Nigeria were analysed. The method compares well with the conventional distillation method. The least squares regression of the two sets of analyses of 40 soils was Y = 0.95 + 0.96 X. However, the direct colorimetric method was more reproducible, faster and simpler than the distillation method.
Colorimetric determination of CEC, indophenol blue, tropical soils
