References of "Legrain, Xavier"
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See detailThe Belgium soil survey project: A heritage to preserve
Legrain, Xavier ULg; Dondeyne, Stefaan; Deckers, Jozef et al

Conference (2012, July 06)

Between 1947 and 1991, soils of Belgium were mapped to establish a systematic inventory of the country soil resources. Field observations were done by soil auger to a standard depth of 1.25 m and at a ... [more ▼]

Between 1947 and 1991, soils of Belgium were mapped to establish a systematic inventory of the country soil resources. Field observations were done by soil auger to a standard depth of 1.25 m and at a mean density of 2 points per hectare. Cadastral plans at scale 1:5,000 where used for georeferencing field observations and for delimiting map units, subsequently generalized on the 1:10,000 topographic base map. The final map was published on sheets at scale 1:20,000 along with descriptive texts. Besides, data on about 15,000 described and analyzed soil profiles were reported in technical annexes. With the advent of computers, data on soil profiles have been transfered into relational databases and soil sheets have been digitized. Coding of the data rendered them more accessible, but inevitably implied a standardization and hence a reduction of some information. Still most of the soil surveyors have already passed away, besides their intangible expert knowledge, a wealth of information is also being lost when their field notes, unpublished reports, minutes of meetings and draft maps are being disregarded. The map legend was developed during the first decade of the survey, reflecting state of knowledge on soil formation and their relative importance for agricultural land-use in the 1950s. To guarantee that future generations will be able to appreciate the value and concepts underpinning the soil information, it is important that at least a minimum set of such historical documents would be preserved, analyzed and documented. [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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See detailLa Carte des Sols de la Belgique, outil d'estimation de la pression urbanistique sur les sols
Legrain, Xavier ULg; Michel, Brieuc ULg; Bock, Laurent ULg et al

Conference (2012, March 20)

Ces dernières décennies, des pressions de tout ordre ont induit une forte expansion de l’urbanisation en Europe, à laquelle la Belgique n’échappe pas. L’imperméabilisation des sols a par ailleurs été ... [more ▼]

Ces dernières décennies, des pressions de tout ordre ont induit une forte expansion de l’urbanisation en Europe, à laquelle la Belgique n’échappe pas. L’imperméabilisation des sols a par ailleurs été identifiée comme une des principales menaces pesant sur eux. Au-delà du constat de l’évolution des surfaces artificialisées en Wallonie, l’objectif de cette étude est d’identifier les sols les plus soumis à ce phénomène. L’élaboration de la Carte Numérique des Sols de Wallonie (CNSW) – à partir d’un document historique, la Carte des Sols de la Belgique levée à grande échelle entre 1947 et 1991 – et de la Carte Numérique d’Occupation des Sols de Wallonie ouvre des perspectives intéressantes à ce sujet. Plus spécifiquement, l’utilisation de cartes d’aptitude des sols pour l’agriculture, dérivées de la CNSW, met en évidence l’impact de l’artificialisation sur la réserve en sols de meilleure potentialité agricole (figure 1). Cette dernière a diminué de 5 % à l’échelle de la Wallonie suite à l’artificialisation des sols ces 60 dernières années. La réalité est plus contrastée à l’échelle locale. La moitié des 262 communes wallonnes se situe en deçà, tandis que d’autres ont perdu (du point de vue agricole) jusqu’à 50 % de leurs meilleurs sols, par ailleurs initialement fortement présents sur leur territoire. Autre constat : si la moitié des communes subit une artificialisation uniforme de ses sols, 20 % d’entre elles voient leurs meilleurs sols préférentiellement artificialisés par rapport à ceux de potentialité agricole moindre.Une analyse spatiale fine à plus grande échelle (figure 2) ouvre la voie à la compréhension des phénomènes en jeu et in fine à l’élaboration de recommandations face à la concurrence inévitable entre deux fonctions essentielles des sols : la production agricole et le support des activités humaines. [less ▲]

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See detailSaving our soil information, making our soil map more understandable, usable and useful in the digital era: contribution of the Digital Soil Map of Wallonia Project
Legrain, Xavier ULg; Michel, Brieuc ULg; Bock, Laurent ULg et al

Scientific conference (2011, December 07)

Due to greater awareness of the necessity to preserve soil functions from human pressure on the environment, the need for soil information is increasing. Supported by the evolution of technologies these ... [more ▼]

Due to greater awareness of the necessity to preserve soil functions from human pressure on the environment, the need for soil information is increasing. Supported by the evolution of technologies these last decades, great efforts were achieved to provide up-to-date, high resolution, continuous data on soil properties. These efforts are valuable and necessary, but they are often restricted to limited surfaces. Morevover, each of these data reveals partial picture of the soil and doesn’t give an insight into their genesis, organisation and functionality. Therefore the Soil Map of Belgium remains an essential resource. On the other hand, foreign (soil) scientists frequently claim that we (the Belgium country) have a prodigious soil map and implicitly conclude we don’t need any more soil information. More questionable, many users of the now available digital soil maps think they obtained the « Holy Grail » allowing them to extract all the information they need about soil. This is clearly not the case, many currently « wanted » soil parameters being either missing, or displaying insufficient precision. But the wealthy potential of the Soil Map of Belgium in itself is not enough nor always advisedly used. Here are some of the multiple reasons to underline: (i) the map and its legend are complex and few people take/have time to (properly) learn it before use ; (ii) the great number of legend units is confusing for users, lacking tools for organising and stratifying their data ; (iii) the easygoing use (from a GIS point of view) of the legend units, due to their concatenated structure and facilitated by the split structure of the digital map’s attribute table, leads incidiously to a clearcut « symbol by symbol » use of the map, coupled with strict definition of the symbols. Hence a sharp loss of information and comprehension emerging from the whole legend unit or linked to the interpretation of the symbols ; (iv) without the undeniable expert knowledge of the generation who made the map, the current users don’t have in mind the regional nuance, the numerous implicit information lying into the legend, the concepts used during the survey and reflecting state of knowledge on soil formation and their relative importance for agricultural land-use in the 1950s ; (v) the new generation is desperatly short of practice of soil observation in the field ; (vi) a wealth of information is also being lost when the field notes, unpublished reports, minutes of meetings and draft maps are being disregarded, as well as other legacy data associated with the map (booklets, monographs, …). This presentation will show through selected examples how the Digital Soil Map of Wallonia Project contribute to overcome this situation in order to reach this ambitious but feasible objective : a better understanding and use of the Soil Map of Belgium by the maximum of people. [less ▲]

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See detailLa Carte des Sols de la Belgique, outil d'estimation de l'érosion
Demarcin, Pierre ULg; Legrain, Xavier ULg; Mokadem, Abdel Illah et al

Poster (2011, November 16)

L’érosion des sols a des conséquences très importantes pour la société, d’ordre agronomique (détérioration de la structure, perte en matière organique et en nutriments, diminution des rendements, … ... [more ▼]

L’érosion des sols a des conséquences très importantes pour la société, d’ordre agronomique (détérioration de la structure, perte en matière organique et en nutriments, diminution des rendements, …), économique (coût pour la collectivité, pour les compagnies d’assurance, …) ou environnementale (eutrophisation, contamination des eaux de surface, …). Le Projet de Cartographie Numérique des Sols (PCNSW) met en œuvre une démarche originale d’estimation de l’érosion historique sur les 50 dernières années. Des sondages à la tarière ont été réalisés sur des sites d’étude en Région limoneuse afin d’estimer l’épaisseur des volumes pédologiques. Ces observations ont été comparées à celles des levés de terrain originaux de la Carte des Sols de la Belgique. Si près de 30 % des sondages ne permettent pas de mettre en évidence une évolution en terme d’érosion, la perte en sols sur 50 ans est estimée à plus de 40 cm dans 30 % des cas. [less ▲]

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See detailExploitation of the Soil map in Belgium
Bah, Boubacar Billo ULg; Legrain, Xavier ULg; Colinet, Gilles ULg

Conference (2011, October 14)

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See detailProduction de cartes généralisées à partir de la Carte Numérique des Sols de Wallonie
Legrain, Xavier ULg; Demarcin, Pierre ULg; Mokadem, Abdel Illah et al

Poster (2011, July 07)

La Belgique est parmi les premiers et rares pays à s’être dotée, entre 1947 et 1991, d’une carte des sols à grande échelle (1/20 000) sur l’ensemble de son territoire. Entretemps, le développement actuel ... [more ▼]

La Belgique est parmi les premiers et rares pays à s’être dotée, entre 1947 et 1991, d’une carte des sols à grande échelle (1/20 000) sur l’ensemble de son territoire. Entretemps, le développement actuel des applications numériques d’une part, une prise de conscience accrue de l’importance de préserver les sols d’autre part, ont amené la Région wallonne à entreprendre la digitalisation de la partie wallonne de la Carte des Sols de la Belgique, pour aboutir à la production d’une couche numérique cohérente sur l’ensemble du territoire wallon, accompagnée d’une légende unique et exhaustive : la Carte Numérique des Sols de Wallonie (CNSW). Sa très grande précision, tant spatiale que sémantique, en fait un outil d’analyse puissant, mais également particulièrement complexe à manipuler. Partant du constat qu’une grande partie du territoire peut être couverte à partir d’un nombre limité d’unités cartographiques parmi les 6 000 existantes dans la CNSW, une carte des Principaux Types de Sols de Wallonie à l’échelle du 1/250 000 en a été dérivée, offrant ainsi une vision d’ensemble et une perspective d’intégration européenne. La légende fut conçue à partir de regroupements logiques des sols sur base de trois des quatre critères majeurs des unités cartographiques de la CNSW, à savoir la texture, le drainage naturel et la nature de la charge caillouteuse lorsqu’elle est présente. Adoptant des principes de dominance par l’utilisation des termes « principalement » ou « quasi-exclusivement », elle ne peut néanmoins être qualifiée de carte d’associations de sols du fait des restrictions de regroupement adoptées. Outre le rattachement de chaque plage cartographique à une des classes ainsi définies, un processus de généralisation cartographique a été effectué dans le but d’une meilleure lisibilité à l’échelle du 1/250 000. Cette carte fut utilisée comme support à la sectorisation du territoire wallon en 24 Districts de l’Espace Rural, sur base d’une analyse à caractère géomorphopédologique. Ces Districts sont à leur tour utilisés pour la réalisation de cartes des Principaux Types de Sols à l’échelle du 1/100 000, sur le même principe que la carte à l’échelle du 1/250 000. Ces diverses cartes généralisées permettent d’envisager la confrontation de la CNSW avec plusieurs gisements de données d’analyse disponibles, selon différentes échelles. En tant qu’outil d’intégration, de structuration et de cadrage de l’information pédologique, elles doivent devenir de plus en plus le fondement de Systèmes Régionaux d’Information sur les Sols et leurs propriétés. [less ▲]

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See detailRévision de la Carte Numérique des Sols de Wallonie - Rapport final
Legrain, Xavier ULg; Demarcin, Pierre ULg; Bouhon, Antoine et al

Report (2011)

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See detailMéthodologie de constitution d'une collection d'échantillons de sols en relation avec les principaux matériaux parentaux en Wallonie (Belgique méridionale)
Legrain, Xavier ULg; Renneson, Malorie ULg; Genot, Valérie ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(S2), 683-697

Over the past few years, there has been growing concern about soils and their properties, thanks to greater environmental awareness. Consequently, existing documents on soil are valuable in risk ... [more ▼]

Over the past few years, there has been growing concern about soils and their properties, thanks to greater environmental awareness. Consequently, existing documents on soil are valuable in risk assessment and for the research of well-adapted solutions. In this context, this paper reviews the main stages of soil mapping in Belgium and presents current works to valorize the Digital Soil Map of Wallonia and update associated databases. Belgium is among the first countries to be completely covered by a detailed soil map (1:20,000). The origin of the Soil Map of Belgium, its realisation between 1947 and 1991, the principles and characteristics as well as the related products are described. But since its publication, due to the increasing need of soil information and thanks to the development of geographical information systems the Walloon part of the map was digitalised between 2000 and 2003 by the Digital Soil Map of Wallonia (DSMW) Project. From this early action at regional level, a selection of immediately derived products is presented and briefly commented. However, if these products go beyond the initial objective of agricultural production increase, they do not always meet the environmental challenges nor the future legislation at European, national and regional levels. To fill this gap, the recent tasks carried out by the DMSW team are presented through a description of their methodological and technical framework. The long-term objective is to build Regional Soil Information Systems based on the use of the Digital Soil Map of Wallonia as a tool of integration, structuring and referencing of pedological information. [less ▲]

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See detailPour un échantillonnage et un conseil agronomique raisonné, les outils d'aide à la décision
Genot, Valérie ULg; Buffet, Dominique; Legrain, Xavier ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(S2), 657-668

Environmental and agronomic issues require always more well thought and suited farmer management of agricultural inputs; soil analysis is therefore an essential tool to support decision. However, for a ... [more ▼]

Environmental and agronomic issues require always more well thought and suited farmer management of agricultural inputs; soil analysis is therefore an essential tool to support decision. However, for a soil analysis to provide valuable information, it is essential for the sample to be representative of the studied field. Without this representativeness, an analytical result, as accurate as it could be, would not be of interest if it could mislead the farmer. In practice, the main difficulty for the sampler is the recognition of soil criteria which are essential to provide a fertility advice, especially in Wallonia (Belgium) where soil variability is very important. With the Digital Soil Map of Wallonia (DSMW), drowned at the scale 1/5,000, it seems appropriate to give these information to the samplers in an useful form for routine works. That is why a mapping tool for decision support, named REQUACARTO, was designed to be used for soil analysis by provincial laboratories, members of the REQUASUD laboratories network. This tool responds to a real requirement in Wallonia: achieving a quality sampling for the development of personalized soil fertility advice. [less ▲]

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See detailCartographie des sols en Belgique : aperçu historique et présentation des travaux actuels de valorisation et de révision de la Carte Numérique des Sols de Wallonie
Legrain, Xavier ULg; Demarcin, Pierre ULg; Colinet, Gilles ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(S2), 647-656

Over the past few years, there has been growing concern about soils and their properties, thanks to greater environmental awareness. Consequently, existing documents on soil are valuable in risk ... [more ▼]

Over the past few years, there has been growing concern about soils and their properties, thanks to greater environmental awareness. Consequently, existing documents on soil are valuable in risk assessment and for the research of well-adapted solutions. In this context, this paper reviews the main stages of soil mapping in Belgium and presents current works to valorize the Digital Soil Map of Wallonia and update associated databases. Belgium is among the first countries to be completely covered by a detailed soil map (1:20,000). The origin of the Soil Map of Belgium, its realisation between 1947 and 1991, the principles and characteristics as well as the related products are described. But since its publication, due to the increasing need of soil information and thanks to the development of geographical information systems the Walloon part of the map was digitalised between 2000 and 2003 by the Digital Soil Map of Wallonia (DSMW) Project. From this early action at regional level, a selection of immediately derived products is presented and briefly commented. However, if these products go beyond the initial objective of agricultural production increase, they do not always meet the environmental challenges nor the future legislation at European, national and regional levels. To fill this gap, the recent tasks carried out by the DMSW team are presented through a description of their methodological and technical framework. The long-term objective is to build Regional Soil Information Systems based on the use of the Digital Soil Map of Wallonia as a tool of integration, structuring and referencing of pedological information. [less ▲]

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See detailSoil redistribution in rural catchment: how fifty years old soil survey can help model improvement
Legrain, Xavier ULg; Colard, François ULg; Colinet, Gilles ULg et al

in Geophysical Research Abstracts (2011), 13

In a context of high urbanization’s pressure in rural zones, landscape modelling of erosion opens interesting perspectives in land use planning. In most cases, validation data are the weak point. In this ... [more ▼]

In a context of high urbanization’s pressure in rural zones, landscape modelling of erosion opens interesting perspectives in land use planning. In most cases, validation data are the weak point. In this study, we present how fifty years old soil observations can help progressing towards a more accurate validation of such modelling in rural areas. As of 1947, a comprehensive systematic survey of the Belgian soil cover was initiated. Field observations were done every 75 meters by soil auger to a standard depth of 125cm (if possible). Map units were delineated on cadastral field survey maps at scale 1:5,000, based on auger observations and landscape context, then generalised on the 1:10,000 topographic base map for a publication at 1:20,000 scale. The legend of the map includes more than 6,000 different soil types and variants. More recently, the Walloon part of this map was digitalised to produce the Digital Soil Map of Wallonia (DSMW). A 10m resolution DEM was build up in 2009. Its RMSE is 0.8m. Soil erodibility and runoff production maps were derived at the same resolution. A land use map exists at 1:10,000 scale since 2005 and is updated yearly. We applied the USPED model (Unit Stream Power - based Erosion Deposition) (Moore and Burch, 1986) in a small watershed where first soil observations took place in 1956. New soil observations were done in 2010. The watershed is completely included in a cultivated area. The model was applied considering a transport capacity limitation proposed by Mitasova and Mitas (1996). Furthermore, we slightly modified it, in order to take into account recent advances in RUSLE factors computations like LS computation proposed by Desmet and Govers (1996) and Nearing (1997). The spatial distribution of erosion and deposition area produced by the model on the basis of the current DEM is consistent with a comparison between old and recent pedological observations. Furthermore, a comparison between horizons’ thickness in 1956 and 2010 gives spatially distributed quantitative information on erosion and deposition. Nevertheless, some uncertainties remain since the pedological descriptions are based on thickness classes, due to the variability of soil cartographical units, and since the current DEM is itself affected by an uncertainty on the elevation value. Future research will then focus on more accurate elevation data as starting point and then it will become conceivable to model the evolution of watershed elevation including land use and other local anthropogenic structures like hedgerows, ditches or grass strips. [less ▲]

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See detailDe la Carte des Sols de la Belgique à la Carte Numérique des Sols de Wallonie : vers des Systèmes Régionaux d'Information sur les Sols et leurs propriétés
Legrain, Xavier ULg; Demarcin, Pierre ULg; Colinet, Gilles ULg et al

in Bulletin du groupe francophone humidimétrie et transferts en milieux poreux (2010, November 25), 56

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See detailValorisation de la Carte des Sols dans un cadre inattendu - Le tourisme à caractère scientifique
Rekk, Samantha; Legrain, Xavier ULg; Bock, Laurent ULg et al

Poster (2010, November 24)

Detailed reference viewed: 25 (4 ULg)