Countdown to the Africa in Profile exhibition!

We are shifting to high gear with the exhibition ‘Africa in Profile’ opening next week! After endless hours of writing, editing, spending time with the graphic designers, selecting pieces and ordering equipment we are almost ready!

Join in for a sneak-preview!


The stars of the show -30 impregnated soil cores (monoliths) from all over Africa – arrive from ISRIC

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Seppe and Florias Mees in the vast archives of Afrikamuseum, selecting geological samples


Some beautiful termite mounts form the collections at Afrikamuseum will be on display as well – this one looks a bit like a Star Wars character…


The monoliths need a safe home here in Belgium, so Christophe designed a display case fit for a star! This is the prototype


Monolith-case mass-production at the main laboratory at the Geo-Institute… not a sight you see every day!

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Panels, labels, displays and posters are ready! Now all that remains is spreading the word – ISRIC’s Soil Museum is taking the lead! 


Africa in Profile – Spread the word!

Just eleven more days and our exhibition “Africa in Profile” opens its doors! 

The exhibition is centered on the ‘Soil Atlas of Africa’ (EU-JRC). As soils are invisible to most, policy makers often recklessly overlook their importance. Hence, good soil maps are a major asset in land-use planning and sustainable development.

The exhibition brings these soil maps to live for a wide audience: the pride of the exhibition is a set of 30 resin-impregnated soil cores, called ‘monoliths’, from all over Africa. Each shows a vertical section of soil (a profile) exactly as it would look in the field. Together with over these 200 impressive photographs, geological samples and archeological materials, these monoliths tell the story of how soils are critical to livelihoods, land-use and biodiversity and what can be achieved if the public, scientists, farmers, policy makers and industry join forces.

The exhibition will be festively opened on December 4th, by Herman Van Rompuy (former EU president), Alexander De Croo (minister for development cooperation), Rik Torfs (Rector KU Leuven) and Bruno Delveaux (Rector UCL). The exhibition is open for the public from 05/12/2015 to 29/01/2016, in Arenbergbibliotheek KU Leuven (W. De Croylaan 6, Heverlee) between 8.30 am and 10 pm on weekdays and between 10 am and 7 pm during the week-end. Entrance is free.

Please help us spread the word by sharing our poster! A high-resolution version for printing can be downloaded here!  

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Soil of the month September: Phaeozems by Stefaan Dondeyne

During the year of soils, each month we ask a soil researcher to select his or her favorite soil. Next up is Dr. Stefaan Dondeyne:

Currently a research fellow at the University of Leuven in Belgium, Stefaan has been involved in converting the legend of the soil map of Belgium to WRB. Over the last 20 years he has mainly worked on natural resources management projects in tropical Africa.

SSSB: If you have to choose a favourite soil, what would it be?

Stefaan: That’s a hard choice. On a worldwide scale, I would have Andosols as number one. Just because a great part of my childhood was on Andosols and I am fascinated by volcanoes. But, here I want to focus on Belgium, and I will say Phaeozems and Umbrisols.

SSSB: What are the main properties of these soil types?

Stefaan: First, in this context we should not use the word “soil types” but really refer to (reference) soil groups. Both groups have in common their thick, dark surface horizons with high content of organic matter. Having a Mollic horizon, the Phaeozems will have relative high base cations saturation (BS ≥ 50%); the Umbrisols are their acidic brothers, so with a BS < 50%.


Fig. 1 – A Rendzic Phaeozem in the valley of the Hoyoux, near Huy, developed on travertine limestone (from the SSSB excursion of 2010) and showing the thick dark surface horizon with high organic matter content

SSSB: Why do you find this soil type particularly interesting?

Stefaan: As a student, when we learned about Phaeozems, we were taught that these are the typical soils of the slightly more humid areas of the steppes, be it in Ukraine or the central parts of the USA. Of course Phaeozems are surely the dominant soil group in these areas, but as the key property is to have a thick dark surface horizon, we find such soils in very varied environments including tropical environments. So they can be found wherever climate or drainage favours the accumulation of organic matter (Fig. 2). The same goes for the Umbrisols, but note that in the FAO legend these were not yet considered as a separate reference soil group but mostly out as Humic Cambisols.


Fig. 2. – Phaeozems occur worldwide: (a) Luvic Phaeozem in Nebraska, USA at 375 m altitude and used for wheat cultivation; (b) Cambic Phaeozem (Andic) in southern Ecuador at an altitude of 3250 m under pine plantation; (c) Luvic Phaeozem (Chromic) in south-eastern Tanzania at an altitude of 300 m and under miombo woodland

In Belgium both Phaeozems and Umbrisols occur mostly in valleys, where they are found in association with Histosols and Gleysols. In the legend of the soil map of Belgium, however, no particular symbol was foreseen for these soil groups. Hence when correlating the Belgian legend to the World Reference Base for soil resources (WRB) for the Flemish region, we inferred their occurrence based on reports on colour in the booklets and statistics on OC content. The wetland areas where these soils occur are considered of importance for nature conservation. In the Walloon region both Phaeozems (Fig. 1) and Umbrisols (Fig. 3c) also occur. Once the conversion of the Belgian soil legend to WRB will also be completed for Wallonia we will get a better overview on their spread and occurrence in Belgium.


Fig. 3. – Phaeozems and Umbrisols in Belgium (a) Gleyic Phaeozem in Meerbeek on alluvial silt deposits (Vl. Brabant) (b) Gleyic Umbrisol on eolian fine sand deposits (Bree, Limburg); (c) Cambic Umbrisol in Gesves on Psammite (Namur)

SSSB: Do the properties of these soil groups have consequences for its management, e.g. in terms of land use, soil quality, …?

Stefaan: Given their high organic matter content, and in the case of the Phaeozems their favourable pH, these soils are highly valued for their fertility and if not too wet, for their good physical properties. Phaeozems in the Flemish region will be about the most productive soils for poplar for example. These soils are also important for their soil organic carbon stocks and their role in carbon sequestration. Therefore, next to the usual suspects as the Histosols and Gleysols, these soil groups deserve special attention when estimating soil organic carbon stocks. As the spread and occurrence of these soils has been underreported in Belgium this calls for particular attention, and highlight the importance of having the soil map of Belgium correlated to WRB.

For more information on the Reference Soil Groups of the Flemish region and the conversion of the soil map of Belgium to WRB:

  • The soil map of the Flemish region converted to the 3rd edition of the World Reference Base for soil resources – available at
  • De grote bodemgroepen van Vlaanderen: kenmerken van de “Reference Soil Groups” volgens het internationale classificatiesysteem World Reference Base – available at

Thematic Day: International Congress and Exhibition ‘Africa in Profile’!

The International Year of Soils 2015 is drawing to a close. The SSSB, together with KU Leuven, EU-JRC, ISRIC, Africamuseum and the African Soil Science Society, have prepared a series of activities to end the year on a bombshell!

The ‘Africa in Profile / Afrika DoorGrond’ exhibition shows the beauty and variability of Africa’s soils, and their importance for both nature conservation as human land-use. The exhibition will be open to the public from December 5th to January 31th, in the Arenberglibrary in Leuven. Entry is free.

On December 4th, an International Conference will be staged, discussing the importance of Soil Information Systems for Africa. The French edition of the Soil Atlas of Africa will be officially launched during this event, and the exhibition will be festively opened by a.o. Herman Van Rompuy, Alexander de Croo and Rik Torfs. For the full program and registration, please visit our website. Contributions in the form of posters are welcomed.

On December 5th – World Soil Day – free guided tours are organised for all those interested. Both people completely new to soil science as soil professionals are most welcome.

On January 15th, a Strategic forum will discuss opportunities and pitfalls for inter-university collaboration and NGO’s regarding sustainable development in Africa. More information can be found here.

Spread the word!


Soil of the month August – Nitisol by Eric Van Ranst

During the year of soils, each month we ask a soil researcher to select his or her favorite soil. Next up in line is Prof. Dr. em. Eric Van Ranst of Ghent University, honorary President of the Society.

Eric Van Ranst (MSc Geology, MSc Soil Science, PhD Earth Sciences) started his professional career in 1976 as an assistant at the International Training Centre for Post-graduate Soil Scientists at Ghent University (ITC-Ghent). After his PhD in 1981 he was fielded for 9 years in Cameroon under the VLIR -Technical University Cooperation as Lecturer in Soil Science at the ‘Ecole Nationale Supérieure Agronomique’ in Yaoundé, and from 1985 until 1990 as Head of Soil Science Department at Dschang University. In 1991 he rejoined Ghent University as Professor and Director of the Laboratory of Soil Science, and since 2001 as Director of ITC-Ghent. His research activities are mainly focusing on understanding the formation and evolution of soils, their properties, functions and quality based on fieldwork and advanced physico-chemical, micromorphological and mineralogical analyses.

SSSB: If you have to choose a favorite soil, what would it be?

EVR: Very difficult question to answer as I do not really have a favorite soil. My so-called favorite soils are time-dependent; in the beginning of my career I was especially focused on Luvisols and Cambisols because of my PhD research, and interested in Podzols under the influence of Frans De Coninck, my supervisor at Ghent University at the time. Once fielded in the humid tropics my research interest turned towards variable charge soils (Ferralsols, Andosols, etc.). So if I have to choose a favorite at present, it will be a Nitisol.

SSSB: What are the main properties of this soil type?

EVR: Nitisols (IUSS Working Group WRB) are deep, well-drained, dusky red to dark reddish brown tropical soils with diffuse horizon boundaries and a clayey ‘nitic’ subsurface horizon that has typical ‘nutty’, polyhedric, blocky structure elements with shiny ped faces; from Latin nitidus, shiny. Nitisols are strongly weathered materials of intermediate to basic parent rock, possibly rejuvenated by recent admixtures of volcanic ash. Nitisols are far more productive than most other highly weathered tropical soils because of their higher fertility and favorable physical properties (good internal drainage, deep rootability and fair water holding properties). Nitisols correlate with the kandic groups of Alfisols and Ultisols of the USDA Soil Taxonomy. More than half of the approximately 200 million hectares of Nitisols world-wide are found in tropical Africa, notably in the highlands (>1000 m) of Ethiopia, Kenya, the Democratic Republic of Congo and Cameroon.

SSSB: Why do you find this soil type particularly interesting?

EVR: The shiny faces of the polyhedral, flat-sided or nutty elements typical for the Nito-argillic horizon of Sombroek and Siderius (1982) and for the nitic properties already attracted my attention during field trips in Africa in the eighties because of the animated discussions on their origin by the experts at the time. Over the last 5 years Nitisols became my favorite soil type during soil surveys in a major Nitisol region in Ethiopia in the frame of a VLIR-IUC project. Why? I was surprised to notice that despite their importance for crop production, Nitisols are a soil group whose nature and genesis are not well documented in the international literature. Published analytical data for these soils seems to be very scarce. The exact origin of the typical morphological characteristics of the nitic horizon is still under debate. So in order to fill this gap and to contribute to a better understanding of the development of nitic horizons, we studied selected soil profiles of a Nitisol region in SW Ethiopia in detail by using advanced analytical techniques.

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Left: A representative Nitisol profile of SW Ethiopia – Right: Typical structure of a nitic horizon showing structure elements that easily fall apart into characteristic polyhedric nut-shaped peds with shiny surfaces.

SSSB: Do the properties of this soil type have consequences for its management, e.g. in terms of land use, soil quality …?

EVR: Our recent research in SW Ethiopia (Geoderma 2015, 243-244: 69-79) reveals several features that contribute to understanding the development of nitic horizon properties and its consequences for soil classification, soil quality and land use. Contributing factors to Nitisol development identified are: (i) the presence of open 2/1 clays, besides dominant kaolinite, resulting in relatively high water-dispersible clay content and high swell-shrink potential, (ii) seasonal cycles of wetting and drying, contributing to strong blocky soil structure development, (iii) recurrent conditions of weak temporary hydromorphism resulting in redistribution of Fe-Mn oxides, and (iv) exceptional Fe oxide characteristics, particularly extremely small particle size. Together with the presence of abundant clay coatings, these Fe oxide characteristics explain the shiny aspect of ped faces that is characteristic of nitic horizons.

Nitisol 3

Micromorphological features of nitic horizons: (a) sub-angular blocky microstructure, with abundant illuvial clay surrounding some of the structural units ( PPL); (b) infilling with granular, partly coalescent, aggregates (PPL); (c) blocky microstructure, showing several generations of planar voids, with clay infillings occupying the older pores, and Fe/Mn hypocoatings superimposed on clay coatings (PPL); (d) same as previous, in XPL; (e) micro-laminated coating/infilling of clay with strong parallel alignment (PPL); (f) same as previous, in XPL.

The studied Nitisols are affected by an admixture of surface-derived volcanic ash components, which might be common in Nitisol regions and which puts into question the use of silt/clay ratio as a requirement for this WRB reference soil group. According to the USDA Soil Taxonomy, the studied soils are classified as Oxyaquic Paleudalf. The oxyaquic criteria are assumed to be met in view of the high annual rainfall (ca. 2000 mm y-1) and concentration in a single rainy season. It is also suggested by the common occurrence of landslides during or shortly after periods of heavy rains, triggered by water saturation. The typical nitic properties, the high rainfall, the cultivation of most parts of the land and to a lesser extent steep slopes, make this Nitisol region very sensitive to landslides. Landslides are a significant problem for the local farmers. Therefore, it is important to look for reliable and sustainable measures. Total reforestation with deep-rooted trees can possibly reduce the landslide risk, although this is not a realistic measure due to the shortage of arable land in this highly populated area.

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Left: A landslide in Nitisols in Ethiopia. Note the tension cracks in the soil beyond the landslide scar. Such features are potential early-warning signs that a possible landslide could be triggered in the near future due to intense rainfall or land clearance – Right: A deforested Nitisol landscape used for arable farming.

SSSB: Can you tell us your most memorable story concerning this soil type?

EVR: My strongest memory related to this soil type is my first field contact with Nitisols (still named Nitosols at that time) in January 1983 during one of the field tours along the slopes of Mount Cameroon. These field tours in the Southwest and Littoral provinces of Cameroon were organized by the Benchmark Soils Project in collaboration with the ‘Institut de la Recherche Agronomique’ (IRA), the Soil Management Support Services (SMSS) and FAO in the frame of the Third International Forum on Soil Taxonomy and Agrotechnology Transfer. I remember very well the first Nitosol profile visited; it was located in the Tole Tea Estate, Saxenhoff Extension, situated on a slope hill at 555 m above sea level; on a fairly old volcanic mudflow and developed in re-deposited pyroclastic materials. This profile was described in December 1980 by the current president of our Society, Bruno Delvaux, FAO expert at the time in the Soil Science Department of IRA at Ekona. At this profile site, I participated for the first time in a discussion on the origin of the ‘irregular, angular, blocky structural elements with common, medium clay skins on shiny ped faces’(as described by Bruno) qualifying the Bt as a Nito-argillic horizon and the soil as Nitosol. During these field trips I became friends with Goro Uehara of the University of Hawaii, who brought me in contact with Gavin Gillman of CSIRO, and both of them were helpful for my further research on Andosols and variable charge soils.

Happy 50th birthday to the soil map of Africa!

In 1965, the first comprehensive Soil map of Africa at a 1: 5.000.000 scale was presented to the Soil Science community in the Bulletin of the International Soil Science Society (which later became the IUSS): read the original announcement here (issue 26, p14). Editor-in-chief of this major endeavour was Jules D’Hoore, former president of the Soil Science Society of Belgium (1976-1977). 

The map was the result of a major correlation exercise, combining all mapping that happened before on the continent and developing a common legend. The map consists of 8 separate sheets, published between 1963 and 1964. The originals are stored at the ISRIC library and scans can be downloaded from the EUDASM archive.

A joint effort of soil specialists of the Commission for Technical Cooperation in Africa of nearly a decade was necessary to tackle this major endeavour, the explanatory monograph mentions over a hundred authors. At the time, Jules D’Hoore was Director of the Inter African Pedological Service.

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Mosaic of the 8 sheets of the Soil Map of Africa by Jules D’Hoore. Source: Soil Atlas of Africa 

While soil names may have changed and boundaries refined, the basic information portrayed on this map proved very reliable. This map has among others formed a solid base for the FAO-Unesco Soil Map of the World at 1:5.000.000 published in 1977 and edited by another SSSB-president: R. Dudal (1994-1995).

The latest major addition to improving our knowledge of the soils of Africa is the Soil Atlas of Africa in 2013. The French edition of this atlas will be launched in december 2015, during the Africa In Profile/Africa DoorGrond exhibition in Leuven.

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Mosaic of the FAO Soil map of Africa (1977) – Map sheets available from the FAO Soils Portal and Soil Map of Africa from the EU-JRC Soil Atlas of Africa (2013)

(by Karen Vancampenhout and Seppe Deckers)

Termite research by UGent finds large mounds may be used on and off for thousands of years

Hans Erens, a researcher from UGent, defended his PhD work on “Origin and implications of variation in properties within Macrotermes falciger mounds” on januari 16th 2015

With this work, supervised by Profs. Eric Van Ranst en Pascal Boeckx, he discovered that termite mounds can be thousands of years old, and that during this period, they are used on and off by different generations of termites. When publishing these remarkable findings in Palaeo3, he caught the attention of the national and international press:

BBC Earth:

De Redactie:

De Standaard:

De Morgen:

Full reference: Erens H., Boudin M., Mees F., Mujinya B. B., Baert G., Van Strydonck M., Boeckx P. & Van Ranst E., 2015. The age of large termite mounds – radiocarbon dating of Macrotermes falciger mounds of the Miombo woodland of Katanga, DR Congo. Palaeogeography, Palaeoclimatology, Palaeoecology 435, 265-271.

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Soil of the month July – Vertisol by Simone Marx

During the year of soils, each month we ask a soil researcher to select his or her favorite soil. Sixth in line is Ir. Simone Marx from the national soil department of Luxemburg of the Ministry of Agriculture, Viticulture and Consumer Protection in Luxemburg.

Simone Marx is head of the soil department since 2007 dealing with soil mapping, profile description, classification and soil analysis. She studied agronomy at the FUSAGX in Gembloux, where she came out with a specialisation in soil science in 1993. Until 2007, she worked for the Chamber of Agriculture in Luxemburg in the farming advice service. Since 2008, several research projects with LIST, UCL, Gembloux Agro-Bio Tech (ULg) as well as contact to belgian and international soil scientists let to a better characterisation, understanding classification and mapping of soils in Luxemburg.

SSSB: If you have to choose a favorite soil, what would it be?

SM: I’m hesitating between sandy soils on the Luxembourg Sandstone (li2) and the clayic soils on Middle Keuper marls and dolomites (km), but my absolute favorite is a Vertisol on a dolomitic marls of the Steinmergelkeuper (km3).

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Endoleptic chromic Vertisol (dolomitic, hypereutric, grumic, endoruptic) in Moesdorf (LU)

SSSB: What are the main properties of this soil type?

SM: Vertisol are not so common in our latitudes. The vertic properties we observe nowadays are inherited from the time these sediments were deposited in the Trias of Mesozoic Area. The main properties are the high content of clay (45-50 %), the shrinking properties of the mixed layered chlorite/smectite (20-25 % of clay fraction) leading in the late spring and summer to opening cracks and self-mulching on the surface. In the pit, you can observe slickensides and wedge shapes aggregates in the Bi horizon (20-80) cm.

Because of the dolomitic substrate, pH is basic. pHwater ranges between 7,5-8,0 and available P, K, Mg concentrations are high. Water content at the wilting point pF 4,2 turns around 20% and reduces available water capacity.

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Slickensides and wedged shapes aggregates


Dryness makes appearing cracks starting on the surface running down to the C-Horizon

SSSB: Why do you find this soil type particularly interesting?

SM: The soil strikes already in the landscape because of the greyish and alternatively reddish colour of the geological material.
Most interesting thing of these soils is their strong structure: because of the shrinking and swelling properties, self-mulching on the 0-2 cm horizon, surface cracks and polygonal pattern of prismatic primary structure breaking into sharp angular blocky aggregate with wedge-shaped ends and slickensides, you literally can observe that the soil is a living body.

SSSB: Do the properties of this soil type have consequences for it’s management, e.g. in terms of land use, soil quality …?

SM: yes, indeed in the first half of the last century, when agriculture was still more depending on the natural fertility of the soils, these soils led to comparatively good yields of wheat because of their naturally alkalinity. But, because of the high clay content, these so-called ‘Minutenböden’ require high skill in cultivation of land and tillage. Minimum tillage should also be best practice. Nowadays, water is pivot of productivity in agriculture and the specific moisture characteristics of these soils (high residual water content, limited water retention capacity) are limiting factors and a natural handicap in a changing world. Nevertheless they stay excellent pasture soils not in terms of quantity but in quality of grass because of high availability of P, K and Mg. Only weathering depth of 40-80 cm can lead to arable land, otherwise permanent grassland is best land use. Very shallow soils on steep slope, oriented south, lead to habitat of Festuco-Brometea. These soils produce also high mineralized wines and tasty fruit. They are eligible for the LFA, less-favoured areas, in Commun Agricultural Policy in Europe because of their clay content and vertic properties.

SSSB: Can you tell us your most memorable story concerning this soil type?

SM: In 2011, we first opened a pit on Vertisol in Moesdorf on Steinmergelkeuper (km3), in the center of Luxemburg, and described it together with Jérôme Juilleret from CRPGL (today LIST –Luxemburgish Institut of Science and Technology). The SSSB visited it in May 2012, but weather conditions were so horribly that nobody could even enter the pit full of water. Therefore, we opened it again this year in spring for visiting purpose. The particularly dry weather of last months creates excellent conditions for seeing vertic structure and vertic properties.

The pit will remain open till September 2015. Contact for visiting: simone  .  marx (at)  asta  .  etat  .   lu   (nvdr: without the spaces).

Visit us in Luxemburg!


Peter Fink (UGent) visiting the profile in Moesdorf in April 2015 with a student group. The profile will remain open for visitors till September 2015. 

Pictures from BDSOL (ASTA& LIST)