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See detailSpatial patterns and morphology of termite ( Macrotermes falciger ) mounds in the Upper Katanga, D.R. Congo
Mujinjya, Baile Baziraké; Adam, Marielle; Mees, Florias et al

in Catena (2014), 114

This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were ... [more ▼]

This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were assessed using high-resolution satellite images for 24 plots of variable size (3 to 27 ha). Soil morphological features were described for five termite-mound profiles of 5 to 9 m depth/height. A mean areal number density of 2.9 ± 0.4 mounds ha−1 is estimated for the degraded miombo woodland of the study area. Spatial statistical analyses document that termite mounds are regularly distributed in all studied plots. The overall mean nearest-neighbour distance between termite mounds is 44.6 ± 0.6 m. The high relative number of inactive mounds in the region, with regular distribution patterns, suggests that current termite mound occurrences are largely relict features.There are no clear indications for an impact of the nature of the parent material on the spatial distribution of the mounds. One aspect of differences in morphology between the studied mounds is that the stone layer occurs at greater depth in topographic low areas than at crest and slope positions. This is interpreted as being mainlyconditionedbyerosion.Mn–Fe oxideconcentrationsoccurringinallstudiedtermite moundprofiles reflect a seasonally high perched water table beneath the mound, which is more pronounced at lower landscape positions. In summary, mound positions in the habitat are consistent with intraspecific competition rather than soil and substrate characteristics as controlling factor, whereas variation in morphological characteristics between termite-mound profiles appears to be a function of the parent material [less ▲]

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See detailSoil classification, map legends and GIS logic: experiences from converting the legend of the soil map of Belgium into WRB
Dondeyne, Stefaan; Legrain, Xavier ULg; Deckers, Jozef et al

Conference (2013, October 04)

A systematic soil survey of Belgium was conducted from 1948 to 1991. The purpose was to have a soil information base adequate for boosting agricultural production after the Second World War. Field surveys ... [more ▼]

A systematic soil survey of Belgium was conducted from 1948 to 1991. The purpose was to have a soil information base adequate for boosting agricultural production after the Second World War. Field surveys were done at the detailed scale of 1:5000, while the maps were published at a 1:20,000 scale. To enable soil surveyors to identify soils in the field, an original soil classification was developed based on readily observable physical and morphogenetic characteristics. Within the European Union, the World Reference Base (WRB) for Soil Resources (IUSS Working Group WRB, 2007), has been adopted as the common classification system. As soil surveys in most European countries were conducted independently, the challenge now is to convert the national legends into a common WRB legend. In Belgium, such a conversion is being implemented and we present some lessons learned in relation to classification and map legends. The legend of the soil map of Belgium is based primarily on soil texture, drainage status and profile development. “Soil series” are defined in an open and non-hierarchical structure by combining these three categorical variables, and to which modifiers can be added such as parent material, stoniness or depth to a substratum. The WRB-2007 classification is based on diagnostic features defined by morphological, physical and chemical properties. The conversion of the legend of the soil map of Belgium to WRB is based on insights gained from classifying, so far, more than 360 legacy soil profiles in combination with field observations. From these insights, heuristic rules have been deduced regrouping soil series into Reference Soil Groups (RSG) and for which some qualifiers could also be identified. Other qualifiers were determined by relying on databases of the legacy soil profiles. To take regional variability into account, the conversion is done by physiographic zone. Converting the legend of the soil map of Belgium to WRB actually leads to a regrouping of soil series into broader WRB categories and which can neatly be represented on 1:50,000 scale maps. Hence, it does not imply substituting one classification with another one. Users, who would need the detailed information, can still refer to the detailed symbols of the soil series. The regrouping of soil series has been made possible thanks to the flexibility of WRB for combining various qualifiers. However, as the WRB-2007 classification leads to a varying number of qualifiers it is less practical for constructing map legends. Therefore, the WRB-2010 guidelines (IUSS Working Group WRB, 2010) propose to organise qualifiers in main and optional ones with priority rules for the main qualifiers. As illustrated in Table 1, this approach may highlight, or hide, some qualifiers inconsistently. When for example only two qualifiers are retained in a map legend, the qualifier Endogleyic of stony, poorly drained Albic Podzols will not be indicated, while it will be indicated when such soils are not stony (Table 1). Moreover, the proposed hierarchy is sometimes also inconsistent when compared across Reference Soil Groups (RSG) as illustrated for the Arenosols and Regosols (Table 1). These drawbacks could be avoided if qualifiers would be organised into thematic groups ― such as profile development, texture, drainage, depth of substratum and fertility ― rather than by ranking them. Grouping qualifiers thematically would have the advantage to give more flexibility to the map user working with GIS, and indeed, it would render WRB a more “GIS logic” classification system. [less ▲]

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See detailConverting the legend of the Soil Map of Belgium into the World Reference Base for Soil Resources: Lessons from correlating national soil survey data to an international soil classification system
Bouhon, Antoine; Dondeyne, Stefaan; Legrain, Xavier ULg et al

Poster (2012, July 03)

Soils in Belgium were mapped between 1947 and 1991 and published at a 1:20000 scale. These maps are used in land consolidation projects and for assessing soils’ vulnerability to erosion and pollution ... [more ▼]

Soils in Belgium were mapped between 1947 and 1991 and published at a 1:20000 scale. These maps are used in land consolidation projects and for assessing soils’ vulnerability to erosion and pollution. Integration of land-use and environmental policies within the European Union however requires a harmonization of different national soil classification systems. With the World Reference Base for Soil Resources (WRB) as common classification system within the Union, the authorities of Flanders and Wallonia commissioned a study to elaborate a methodology for converting the Belgian soil legend into WRB. The Belgian legend is based on field properties such as texture, drainage status and profile development. The WRB classification is based on diagnostic features defined by morphological, physical and chemical properties. A key and software programme have been developed to convert the Belgian units into WRB units. However, as many Belgian units could not unequivocally be translated into WRB units, additional guidelines had to be derived based on soil survey data classified according to WRB. The data show that principles of the legend shifted over time or were interpreted differently to take regional specificities into account. To overcome resulting ambiguities it is proposed to establish a database of reference soil profiles. Whereas, overall WRB is satisfactory for classifying soils at national level, the experience also shows that some WRB concepts may benefit from revisions to facilitate its correlation with national soil survey data. [less ▲]

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See detailConverting the legend of the Soil Map of Belgium into the World Reference Base for Soil Resources: Strenght and constraints of using WRB as a map legend
Dondeyne, Stefaan; Bouhon, Antoine; Legrain, Xavier ULg et al

Conference (2012, July 03)

Within the European Union, there is a general interest to prepare joint soil maps at a 1:250000 scale in order to harmonise agricultural and environmental policies. The World Reference Base for Soil ... [more ▼]

Within the European Union, there is a general interest to prepare joint soil maps at a 1:250000 scale in order to harmonise agricultural and environmental policies. The World Reference Base for Soil Resources (WRB) has been adopted as the common soil classification system within the EU. As soil surveys in most member states were conducted independently, the challenge is now to convert the national legends into a common WRB legend. Based on our experiences from converting the legend of the Soil Map of Belgium to WRB, we discuss the strengths and constraints of using WRB for both large scale (1:50000) and small scale (1:250000) maps. By using WRB Reference Soil Groups with one or two main qualifiers, the principal soil information of the original 1:20000 scale Soil Map of Belgium can be represented. Inevitably the conversion to WRB leads to some loss of information as details on soil texture, drainage and substratum get generalised into broader categories in WRB. This generalisation however can be neatly presented on 1:50000 scale maps. Being less complex than the original maps, these maps have the advantage to provide better insights into the regional soil geography. Moreover, as they are built on international classification concepts, the historical soil maps are made accessible to a wider audience. The conversion into WRB units also allowed for a straightforward generalisation and production of small scale maps (1:250000) which should be suitable for producing a soil map at European level. [less ▲]

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