3.2.5 A summary of chemical data
Overall, in terms of chemistry, soils in Anak Krakatau and also profiles Panjang1, Rakata1, and Sebesi1, which all were located at a higher elevation, showed the least development. Soils at the coast of Rakata and Sebesi showed a reasonable development in terms of higher pH, CEC, and OC content. In contrast, soils in Sebesi were most developed with higher values of pH, CEC, OC, and Alo, Sio, and Feo.
In summary, we performed a linear discriminant analysis on the soil chemical properties as a function of the four islands. We combined data on each isle at all depths as a group as the profile data represents the typical soil materials in the area. In addition, there was minimal soil development, and soil depth variation can only be seen in a few properties (e.g., O C, CEC). Figure 9 shows the biplot of the first two canonical axes of the discriminant analysis. It confirms that soils of Rakata and Panjang displayed similar properties, but they were distinct from the soils of Sebesi and Anak Krakatau. Soils of Sebesi had chemical characteristics (higher CEC, Sio, Alo, Feo), indicating a more developed stage than soils of the other islands. Soils in Anak Krakatau were least developed (Figure 9).