ANDOSOLS OF EUROPE
Soil Resources of European Volcanic Systems

  Year 1998 
  Year 1999 
  Year 2000 
  Year 2001 
  Year 2002 
    Germany 
    Hungary 
  Year 2003 

HUNGARY MEETING 18-22 september. 2002

Program Abstracts Excursion Pictures Participants Invited speakers

Dr.Christl Buhmann,
ARC-Institute for Soil, Climate and Water, Private Bag X79, Pretoria 0001. South Africa


e-mail : C. BUHMANN CBUHMANN@iscw.agric.za

The summary of her lecture on is as follows:

Soils developed from volcanic rocks in South Africa: classification, textural, chemical and mineralogical properties, land use and susceptibility to erosion by C. Bühmann, D. P. Turner & A.J. van Zyl, ARC-Institute for Soil, Climate and Water, Private Bag X79, Pretoria, South Africa.

Volcanic rocks in South Africa occur in a great variety of different geological formations, the oldest of these dating back 3.6 billion years. The two most important volcanic events, as far as the spatial extent of the lava flow is concerned, are associated with the Ventersdorp formation (2.6 billion years) and the Karoo Supergroup (180 Million years). Venterdorp lava crops out east of Vryburg, west of Pretoria, and consists of massive andesitic beds and some tuffaceous quartzite layers. Karoo volcanics consist of basalts and rhyolites and occur in three major outcrops areas: east, south and particularly south-west of Lesotho, in the Springbok Flats north-east of Pretoria and along the Lebombo monocline, a 25 km broad belt, ranging from the Natal coast northward along the border of Mozambique into Zimbabwe. The western half of this volcanic deposit consists of basalt, the eastern half of rhyolite.
The annual precipitation in the areas underlain by volcanic rocks ranges from > 2000 mm in the Highland of Lesotho to < 400 mm in the northern part of South Africa. Climate exerts a significant influence on soil morphology, genesis and classification. In drier regions, Vertisols and Mollisols predominate, although red, well-structured soils with a high base status (Alfisols) are not uncommon. In some localities, calcrete precipitates. As the climate becomes wetter, Oxisols and Ultisols are formed, and finally, in the high rainfall areas east of Lesotho, soils with a humic and occasionally even organic (organic carbon content of > 10%) A horizon are present. Red and black complexes are a striking pedological feature in many areas, with red (Alfisols, Oxisols, Ultisols) earths occupying crest and upper slope positions and black (Vertisols, Mollisols) soils areas of subdued relief. In the red and black complexes of the Springbok Flats, however, differences in hue are not related to relief but to solum thickness and lateral water movements.
Clay mineral associations are strongly soil form related, Vertisols being dominated by smectite or vermiculite, Mollisols generally by an association of smectite and kaolinite while Oxisols, Ultisols and soils with a humic A horizon are dominated by kaolinite, HIV or gibbsite, generally by an association of at least two of these minerals. The soils are mostly clay-textured, though major amounts of sand-sized quartz of aeolean or colluvial origin are common in some profiles. Chemical parameters are also closely associated with soil form: Vertisols and to a lesser extent Mollisols and Alfisols are rich in bases, particularly Ca and Mg, and have a neutral to slightly acid pH. Oxisols and Ultisols are much poorer in bases, often acid, and may be characterized by exchangeable Al at toxic levels.
Land use is closely climate-dependent. In areas with less than 400 mm annual precipitation, cattle and game farms predominate, while under higher rainfall conditions (>500 mm), wheat, maize, sorghum, sunflower and cotton are produced. In Natal, sugarcane is grown. In the high rainfall, mountainous area east of Lesotho, the Drakensberg, tourist resorts abound.
Interrill erodibility and aggregate stability determinations, based on rainfall simulator experiments, indicate that both Mollisols and humic Ferralsols are very stable and only slightly prone to erosion.


CURRICULUM VITAE DR. CHRISTL BÜHMANN 

Institute for Soil, Climate and Water of the 
Agricultural Research Council

ADDRESS: ARC-Institute for Soil, Climate and Water, Private Bag X79, PRETORIA 0001
TEL: (012) 310 2525
FAX: (012) 323 1157
E-Mail ADDRESS: CBuhmann@iscw.agric.za

PERSONAL DETAILS

SURNAME: Bühmann, neé Sattler 
FIRST NAME: Christl
DATE OF BIRTH: 1944-03-05
NATIONALITY: German
LANGUAGE PROFICIENCY: English, German
ACADEMIC QUALIFICATIONS

1966 Vordiplom (B.Sc.) in Geology; Univ. of Munich, Germany
1969﷓1970 Study interrupted due to birth of first child 
1971 Diplom (M.Sc.) in Mineralogy; Univ. of Göttingen, Germany
1971﷓1983 Housewife and mother 
1987 Ph.D. in Soil Science University of Natal, Pietermaritzburg, South Africa

PROFESSIONAL STATUS

Lecturer in Clay Mineralogy.
External examiner for 
i) Clay Mineralogy Courses (University of Natal, PMB, University of Pretoria) for the last 8 years.
ii) PhD. Theses submitted at the Annamalai University, India. 
Supervisor for M.Sc. Theses.
Organizer of international meeting, attended by researchers of 11 different countries/ 5 different continents.
Medal for best oral presentation at the Joint Congress 1995, Stellenbosch.
Medal for exceptional performance in 1998, presented by the ARC.
Medal for best oral presentation at the SSSSA Congress 1999, Pretoria.
Second Price for poster at the 2nd Intern. Conference on Land Degradation, Khon Kaen, Thailand, 30/01 - 02/02/1999.
Referee (on request) for the following international journals: Australian Journal of Soil Research; Applied Clay Science; CATENA; Clay Mineralogy; GEODERMA
BOOK REVIEWS (on request) for Sedimentary Geology and Applied Clay Science.

FIELDS OF SPECIALITY

. Mineral weathering
. Soil erosion
. Soil mineral - fertiliser interactions
. Soil forming factors
. Mineralogy in relation to soil taxonomy
. Geology - soil - interrelationships

PROFESSIONAL CAREER

from 1987 Project researcher in national Programs 
from 1989 Soil scientist at the Soil and Irrigation Research Institute (now Institute for Soil, Climate and Water), Pretoria
from 1990 Senior soil scientist at above institute 
from 1991 Principal soil scientist at above institute
from 1998 Specialist scientist and chief researcher at above institute

LIST OF PUBLICATIONS

Bühmann C., 1971. Tonmineralogische Untersuchungen an einer glaukonitführenden Schichtenfolge der Helmstedter Tertiärmulde M.Sc. Thesis (unpubl.), Georg – August University, Göttingen. pp 127.
Bühmann C., Fey M.V. and De Villiers J.M., 1985. Aspects of the X﷓ray identification of swelling clay minerals in soils and sediments. South Afr. J. Sci. 81, 505﷓509.
Bühmann C., 1987. 2:1 Layer Silicates in Southern African Soils. Ph.D. Thesis (unpubl.), University of Natal, Pietermaritzburg. pp 301.
Bühmann C., 1988. Clay minerals as palaeoenvironment indicators. Geobulletin 30, 3-12.
Bühmann C., de Villiers J.M., and Fey M.V., 1988. The Mineralogy of four heaving clays. Appl. Clay Sci. 3, 219﷓236.
Bühmann D. and Bühmann C., 1988. Glaciogenic phosphorites in Natal. Int. Correl. Program, Newsletters, 16.
Bühmann D., Bühmann C., and von Brunn V., 1989. Glaciogenic banded phosphorites from Permian sediments. Econ. Geol. 84, 741﷓750.
Bühmann C., 1990. Weathering profiles on Archaean granites. Proc. 16th Congress of the Soil Sci. Soc. of S. Africa, Pretoria, 315﷓326.
Bühmann C. and Bühmann D., 1990. Clay minerals as palaeoenvironment indicators, exemplified on a Karoo sequence from the Bothaville area, South Africa. S. Afr. J. Geol., 93, 505﷓513.
Bühmann C. and Bühmann D., 1990. Phyllosilicates in hydrothermally altered dolerite sills. S. Afr. J. Geol., 93, 446﷓453.
Bühmann C., 1991. Clay mineralogical aspects of thermally Induced parent material discontinuity. Appl. Clay Science 6, 1﷓19.
Bühmann C. and Grubb P.L.C., 1991. A kaolin/smectite interstratification sequence from a red and black complex. Clay Miner., 26, 343﷓358.
Bühmann C. and Kirsten W.F.A., 1991. A mineralogical investigation of five weathering profiles developed from Archaean granite. S. Afr. J. Plant Soil 8, 146﷓152.
Bühmann C., 1991. Burial diagenetic and contact metamorphic illitization in Permian sedimentary rocks from South Africa.7th Euroclay Conference, Dresden, Proceedings Volume, 166﷓172.
Bühmann C., 1992. Conversion of smectite to illite in a lithologically and thermally complex Permian sedimentary sequence. Clays Clay Miner. 40, 53﷓64.
Bühmann C., 1993. Contact﷓metamorphic illitization and related consequences for the functioning of backfill barriers in high level radioactive waste repositories. S. Afr. J. Sci. 89, 442﷓446.
Bühmann C., 1993. K﷓fixing phyllosilicates in soils: the role of inherited components. J. Soil Science, 44, 347﷓360.
Singer A., Kirsten W.F.A. and Bühmann C., 1993. Occurrence of sepiolite in the northern Transvaal, South Africa. S. Afr. J. Geol. 95, 165﷓170.
Bühmann C., Kirsten W.F.A., Paterson G.P. & Sobczyk, M.E. 1993. Pedogenic differences between two adjacent basalt﷓derived soil profiles I. Soil physical and chemical characteristics.S. Afr. J. Plant Soil 10, 155﷓161.
Bühmann C., Paterson G.P. & Kirsten W.F.A. 1994. Pedogenic differences between two adjacent basalt﷓derived soil profiles II. Mineralogical properties. S. Afr. J. Plant Soil 11, 5﷓11.
Bühmann C., 1994 Parent material and pedogenic processes in South Africa. Clay Miner. 29, 239﷓246.
Singer A., Kirsten W.F.A. and Bühmann C., 1994. Clay dispersitivity and crusting of soils determined by Buchner Funnel extractions. Austr. J. Soil Res. 32, 465﷓470.
Singer A., Kirsten W.F.A. and Bühmann C., 1995. Fibrous clay minerals in the soils of Namaqualand, South Africa: characteristics and formation. GEODERMA 66, 43-70.
Bühmann C. and Schoeman J.L., 1995. A clay mineralogical characterisation of vertisols from the northern regions of the Republic of South Africa. GEODERMA 66, 239-257.
Bühmann C., 1995. The swelling capacity of illite/smectite interstratifications. Acta Universitatis Carolinae Geologica, 38, 127-137.
Bühmann, C. 1995. Mineralogical and chemical properties of crusting and self-mulching Vertisols from South Africa. Proc. ARC-ISCW Symposium on Wise Land Use, Pretoria 1995, Sigma Press, Pretoria, 54-60.
Van der Merwe, G.M.E. & Bühmann, C., 1995. Water infiltration capacity of selected South African soils. Proc. ARC-ISCW Symposium on Wise Land Use, Pretoria 1995, Sigma Press, Pretoria, 65.
Bühmann C., Rapp I. and Laker M.C., 1996. Differences in Mineral ratios between disaggregated and total clay fractions in some South African soils as affected by amendments. Austr. J. Soil Res. 34, 909-923. 
Bühmann, C., van der Merwe, G.M.E., Rapp, I. & Laker, M.C., 1997. Water infiltration and crust formation characteristics of South African soils. Eighth South African National Hydrological Symposium, Pretoria. Proceedings CD. 
Bühmann, C., Rapp, I., Laker, M.C. & van der Merwe, G.M.E., 1998. AGGREGATION: the soil texture approach. Bull. Egyptian Geogr. Soc. 71, 113-135. 
Singer, A., Kirsten W.F.A. & Bühmann, C., 1999. A proposed for deposition mechanism for the formation of salt efflorescenes in the Mpumalanga Highveld, Republic of South Africa. Water, Air and Soil Pollution, 109/1-4, 313-325.
Bühmann, C., 1998. Contact metamorphic illitization: a natural analogue to backfill barriers in high level radioactive waste repositories. Proc. IAEA RCM, Mumbai; 1-29.
Bühmann, C., Samadi, M & Kirsten, W.F.A., 1998. Compositional characteristics of granite-derived soils in relation to topography and climate. 16ème Congrès Mondial de Science du Sol, Montpellier, France, Aug, 1998. Proceedings CD, Sym.15, Nr. 1899.
Bühmann, C., van der Merwe, G.M.E., Rapp, I. & Laker, M.C., 1999. Water infiltration and crust formation characteristics of South African soils. 2nd Intern. Conference on Land Degradation, January 1999, Khon Kaen, Thailand. Proceedings CD.
Bühmann, C. & Nel, J.P., 1999. Clay mineral associations in soils formed under a mediterranean-type of climate in South Africa. Proc. CD of the 6th Int. Meeting of Soils with a Mediterranean type of Climate, Barcelona, Spain, July 4-9, 1999. 
Van der Merwe, A.J., de Villiers, M., Bühmann, C., Beukes, D.J. & Walters, M.C., 2001. Vertisol Management in South Africa. In: The Sustainable Management of Vertisols (Syers J.K., Penning de Vries, F.W.T. & Nyamudeza, P., eds).CABI Publishing, CAB International, Wallingford, UK, pp 85-100.
Van der Merwe, G.M.E., Laker, M.C. & Bühmann, C., 2002. Clay mineral associations in melanic soils of South Africa. Austr, J. Soil Res. 40, 94-114.
Van der Merwe, G.M.E., Laker, M.C. & Bühmann, C., 2002. Factors that govern the formation of melanic soils in South Africa. GEODERMA (in press).

CONFERENCE CONTRIBUTIONS PUBLICATIONS IN ABSTRACT VOLUMES

Bühmann C., de Villiers J.M., and Fey M.V., 1985. The clay mineralogical basis of potassium fixation. Proc. Int. Potassium Symp., Pretoria, 63﷓65. 
Bühmann D., and Bühmann C., 1987. Phosphorites from Glaciogenic Dwyka sediments in Natal, South Africa. 14th Colloquium of Afr. Geol., TU Berlin, Abstract Volume, 113.
Bühmann C. and Bühmann D., 1988. Illite/smectite interstratifications as geothermometer: application to the coal measures of the Vryheid Formation. Geocongress '88, Durban, Extended Abstracts, 63﷓66.
Bühmann D., Bühmann C., and Lepper J., 1989. Changes in depositional environment of Karoo sedimentary rocks from southern Africa. 9th Int. Clay Conf. Strasbourg, Session 8, Abstract 166.
Bühmann C., 1990. Weathering profiles on Archaean granites. Proc. 16th Congress of the Soil Sci. Soc. of S. Africa, Pretoria, 315﷓326.
Bühmann D., Bühmann C., and Lepper J., 1990. The environment Of deposition of Karoo sedimentary rocks. Geocongress '90, Cape Town, Extended Abstracts, 72﷓75.
Bühmann C., 1992. Regional and local aspects of thermally Induced parent material discontinuity. 17th Congress of the Soil Sci.Soc. of S. Afr., Stellenbosch, Abstract volume 11, 3.1﷓3.6.
Singer A., Kirsten W.F.A. and Bühmann C., 1992. Salt efflorescences by atmospheric pollution in the Eastern Highveld. 17th Congress of the Soil Sci. Soc. of S. Afr.,Stellenbosch, Abstract volume, 3A 2.1﷓2.7.
Bühmann C., 1994. The swelling capacity of illite/smectite interstratifications. XIIIth Conference on Clay Mineralogy and Petrology, Prague, Abstract volume, Abstr. 17.
Bühmann C., 1994. A clay mineralogical characterisation of Modal vertisol profiles from the northern regions of the Republic of South Africa. 18th Congress of the Soil Sci. Soc. of S. Africa, Potchefstroom, Abstract volume, 1﷓3.
Bühmann C., Rapp I. and Laker M.C., 1995. Differences in mineral ratios between dispersed and total clay fractions in some South African soils as affected by amendments. Joint Congress 1995, Stellenbosch; Abstract volume, p. 21. (Medal for best paper of a senior author)
Sobczyk M.E. & Bühmann C., 1995. Quantification of soil smectite: the role of analytical technique. Joint Congress 1995, Stellenbosch; Abstract Volume, p. 122.
Bühmann, C., Rapp, I. & Laker, M.C., 1996. Aggregate stability characteristics of selected South African soils as influenced by soil amendments. 20th Congress of SSSSA, Bloemfontein. Abstract Volume, p. 9.
Le Roux, P.A.L., du Preez, C.C. & Bühmann, C., 1996. Verband tussen ferrolise en herverspreiding van Fe-Mn redoxmorfe gronde van die Oos-Vrystaat. 20th Congress of SSSSA, Bloemfontein. Abstract volume, p. 39
Sobczyk, M.E. & Bühmann, C., 1996. Soil Erosion: a geologic perspective. 20th Congress of SSSSA, Bloemfontein. Abstract Volume, p. 69.
Van der Merwe, G.M.E., Bühmann, C., Rapp, I. & Laker, M.C., 1996. Water infiltration capacity of selected South African soils: its dependence on soil characteristics, degree of mechanical disturbance, wetness status and soil amendments. 20th Congress of SSSSA, Bloemfontein. Abstract Volume, p. 79.
Bühmann, C., 1996. Extrapolation of short-term observations to time periods for isolation of long-lived radioactive wastes.CRP Meeting of the International Atomic Energy Agency, Vienna, pp.21. 
Bühmann C., Rapp I. Laker M.C. & van der Merwe, G.M.E., 1997. Aggregation: the soil texture approach. Soil Degradation and Desertification Symposium 1997, Cairo, Egypt. Abstract Volume, p. 7.
Bühmann, C., van der Merwe, G.M.E., Rapp, I. & Laker, M.C., 1997. Water infiltration and crust formation characteristics of South African soils. Eighth South African National Hydrological Symposium, Pretoria. Abstract CD.
Bühmann, C., Botha, M.J. & Kirsten, W.F.A., 1998. Mineralogical evolution of three toposequences developed from Archaean granite. Combined Congress, January 1998, Natal. Abstract Volume p. 29.
Bühmann, C., 1996. Extrapolation of short-term observations to time periods for isolation of long-lived radioactive wastes.CRP Meeting of the International Atomic Energy Agency, Mumbai, India, pp.21. 
Sobczyk, M.E., Bühmann, C. & Botha, M.J., 1998. Textural and chemical characteristics of granite derived soils in relation to topography and climate. Combined Congress, January 1998, Natal. Abstract Volume p. 71. 
Van der Merwe, G.M.E., Laker, M.C. & Bühmann, C., 1998. Melanic soils in South Africa: Parameters that govern their formation. Combined Congress, January 1998, Natal. Abstract Volume p. 79.
Bühmann, C., Samadi, M & Kirsten, W.F.A., 1998. Compositional characteristics of granite-derived soils in relation to topography and climate. 16ème Congrès Mondial de Science du Sol, Montpellier, France. 20-26 Aug. 1998. Abstract Sym. 15, Nr. 1899.
Bühmann, C., 1998. Contact metamorphic illitization: a natural analogue to backfill barriers in high level radioactive waste repositories. CRP Meeting of the International Atomic Energy Agency, Greenway Woods, South Africa, pp. 10. 
Bühmann, C., van der Merwe, G.M.E., Rapp, I. & Laker, M.C., 1999. Water infiltration and crust formation characteristics of South African soils. 2nd Intern. Conference on Lan Degradation, January 1999, Khon Kaen, Thailand. Abstract volume p. 140. (Second prize for best poster)
Bühmann, C. & Nel J.P., 1999. Clay mineral formation and transformation processes in soils from the Western Cape Province. 22nd Congress of the SSSSA, 28 06 - 01 07, 1999, Pretoria, Programme and Abstract Volume p. 11-14. (Medal for best paper of a senior author)
Bühmann, C. & Nel J.P., 1999. Clay mineral associations in South African soils formed under a mediterranean-type climate.6th International meeting on soils with a Mediterranean- type of Climate, July 1999, Barcelona, Spain. Extended Abstracts p. 700-702.
Bühmann, C., Kertész, A. & Papp, S., 2000. Soil erosion: a mineralogist's viewpoint. Erosion workshop, Hammanskraal, Pretoria, 12-13 July 2000. 
Van der Merwe, G.M.E., van Zyl, A.J., Bühmann, C., Kertész, A., Papp, S. & Huszár, T., 2000. Erodibility of South African Mollisols. Erosion workshop, Hammanskraal, Pretoria, 12-13 July 2000.
Van der Merwe, G.M.E., van Zyl, A.J., Bühmann, C., Kertész, A., Papp, S. & Huszar, T., 2001. Interrrill erodibility of melanic soils from South Africa. 23rd annual SSSSA conference, Pretoria, 15-19 January 2001. Abstract volume p. 269.
Bühmann, C. & Beukes, D.J., 2001. Potential sources for increased Al in KwaZulu/Natal subsoils. Int. Symp. on Plant-Soil Interactions at low pH, 12-16 March, 2001, Natal, South Africa, Abstract volume p.25.

REPORTS (unpublished)

Bühmann, C., 1987. Sedimentary petrology of coal-bearing Ecca sediments. Department of Geology and Mineralogy; University of Natal, Pietermaritzburg; pp: 27
Bühmann, C., 1988. Changes in mineralogical composition of Karoo sedimentary rocks from core SR1/75. Department of Geology and Mineralogy, Univ. of Natal, Pietermaritzburg. pp: 24.
Bühmann, C., 1989. The Mineral matter in the Nr. 2 coal seam of the Witbank Coal Field. Geological Survey, Pretoria. pp: 25.
Bühmann, C., 1997. Extrapolation of short-term observations to time periods for isolation of long-lived radioactive wastes: The composition of illite/smectite interstratifications in relation to contact metamorphic temperatures in the vicinity of a dolerite sill. Annual report to the IAEA, Vienna. pp: 18.
Bühmann, C., 1996. Holocene denudation in South Africa: Variations in clay mineral associations of borehole cores H 2-7. pp: 5.
Bühmann, C., 1998. Extrapolation of short-term observations to time periods for isolation of long-lived radioactive wastes: Swelling capacity of illite/smectite interstratifications. Annual report to the IAEA, Vienna. pp: 28.


Last modified 30 October 2003 by EG