Termite mound (heuweltje) cross-sections in Namaqualand, South Africa
These data present soil profile descriptions and photographs of transects through termite mounds known as heuweltjies the semi-arid to arid Namaqualand region in the Northern Cape Province of South Africa. Two heuweltjie mounds near the town of Buffelsrivier in the Buffels River valley, approximately 43 km west of Springbok, were excavated with a 220 PC Komatsu excavator. These heuweltjies were labelled H1 and H4. Location H1: -29.766540° 17.636620°. Location H4: -29.762680° 17.639690° Chemistry data is included for H1 and H4 The sample numbers for H1 and H4 are in the form: HX-Y-Z where HX refers to which specific heuweltjie the sample is taken from and can be either H1 or H4; Y is the cross section distance from the west end of the heuweltjie, in metres, at which the sample was taken (1 – 58 m), and Z refers to the depth, in cm, down the specific sediment profile at that point. For example, if a sample was taken for H1 at a cross section distance of 4 m and a depth of 30 cm, the sample is called H1-4-30. If only HX-Y is mentioned, with no Z, this refers to the entire soil profile at that distance from the west end. A third heuweltjie was sampled in the open face of a mining excavation on the farm Nuttabooi. Location: -29.576843°; 17.362836°. Sample name prefix NB. Location Kleinzee: Termite nests and activity in the sidewalls of mining excavations on the coast north of the Buffels River mouth near the town of Kleinzee (Kleinsee). Co-ordinates given in file at each location. Location Koingnaas: Termite nests and activity in the sidewalls of mining excavations on the coast south of the Buffels River mouth near the town of Koingnaas. Co-ordinates given in file at each location. The folder named termite pictures includes pictures and descriptions all the termites identified in the field areas.
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Soil chemistry 1:1 soil: DI water extracts were prepared for the grid samples (selecting profiles every second meter) and the horizons of the 15 representative profiles from both heuweltjies. The samples were shaken for an hour, as outlined by Rhoades (1996), and extracted through suction filtration with Buchner funnels collecting the water in plastic containers. The extracts were further filtered with 0.45 µm cellulose acetate filters. The extracts were analysed for pH and EC using Eutech pH700 and Eutech CON700 probes, respectively. Major anions were analysed via ion chromatography while cations were analysed using ICP-AES (Thermo iCAP 6200) at the Central Analytical Facilities at Stellenbosch University. Alkalinity was measured using a 702 SM Titrino automatic titrator with a standard 0.1 M HCl solution. Phosphate analysis was performed colorimetrically following the procedure outlined by Murphy & Riley (1962). Dissolved silica was analysed using the blue silicimolybdous method outlined by Jones and Dreher (1996). Jones, R.L., Dreher, G.B., 1996. Silicon. In: D. Sparks, P. A, H. P, L. R, P. Soltanpour, T. MA, J. CT, S. ME (Eds.), Methods of Soil Analysis. Soil Science Society of America, Madison. WI, pp. 627-637. Murphy, J., &; Riley, H. P. (1962). A modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta, 27, 31–36. Rhoades, J.D., 1996. Salinity: Electrical conductivity and total dissolved solids. In: D.L. Sparks (Ed.), Methods of Soil Analysis. Part 3. Chemical Methods. Soil Science Society of America, Madison, WI, pp. 417-437.