LOF.RTF
- 1. LIST OF FIGURES Figure 2.1: Map of South Africa showing the position of Mpumalanga province.............................................................................................18 Figure 2.2: Sampling sites and the basic geology of the Sabie area....................20 Figure 2.3: View from north west to south east from between compartments M-27a and M47a, of the Rhenosterhoek forest area.........................21 Figure 3.1: pHKCl values in forest soils of different ages and their adjacent Grasslands, in the Eastern Transvaal and the Natal Midlands.............................................................................................33 Figure 3.2: Acidity status in surface soils from commercial forest plantations of different ages in the Eastern Escarpment....................35 Figure 3.3: Relationship between exchangeable Al (in aqueous solution of 1M KCl) and pHKCl..........................................................................36 Figure 3.4: Changes in exchangeable basic cations / acidity ratio in soils in relation to compartment age. The Age group of 0 to 10 consists of forest compartments and their adjacent grassland soils. (data source: current study, du Toit (1993) and Nowicki (1997)).......37 Figure 3.5: Amount of Al extracted by 1M KCl and 1M CuCl2 from the soil collection............................................................................................38 Figure 3.6: Amount of Al removed by CuCl2 in relation to the organic carbon (%) present in the soil collection............................................39 Figure 3.7: State of base saturation (BS) in grassland soils and forest soils of different ages in the Eastern Escarpment and Natal Midlands......40 1
- 2. Figure 4.1: Major cation composition of saturated paste extracts of the soil collection. Concentrations (Y axis) are presented in mmolc/l.......47 Figure 4.2: Major anion composition of saturated paste extracts of the soil collection. Concentrations (Y axis) are presented in mmolc/l. Anion deficit was calculated as the difference between the sum of inorganic cations (Figure 4.1) and anions......................................48 Figure 4.3: EC levels in surface soils of pine forest soils of different ages and of their adjacent Grasslands...............................................50 Figure 4.4: Saturation indices of four selected minerals (quartz, kaolinite, gibbsite and jurbanite) for three various MINTEQA2 modeling outputs (With DOC&F, without DOC&F, Without DOC), at the pH range of the saturated pastes.......................................................55 Figure 4.5: Changes of soil solution saturation indices as a factor of pH (saturated paste) with respect to gibbsite and Al-OM complexes......56 Figure 4.6: Distribution of various Ca/Al ratios in soil solution of pine forest surface soils of different ages and of grasslands in the Sabie area..........................................................................................58 Figure 4.7: BC/AC ratio on the exchangeable sites and Ca/Al molar ratio in soil solutions of forest compartments of different ages and of natural grasslands in the Eastern Escarpment and the Natal Middlands...........................................................................................64 Figure A1: Schematic map of the Rhenosterhoek plantation.................................I Figure A2: Schematic map of the Blyfstaanhoogte plantation...............................II Figure A3: Schematic map of the Grootfontein plantation....................................III 2
- 3. Figure A4: Schematic map of the In Die Diepte plantation...................................IV Figure C.1: pH values of saturated pastes and extracts of 22 surface soils under pine plantations of different ages in the Sabie area, Mpumalanga.....................................................................................XV Figure C.2: pH values of three successive measurements in extracts of soil solution for 11 surface soils under pine plantations of different ages in the Sabie area, Mpumalanga................................................XV 3