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See detailDevelopment of a regional-scale library of near infrared reflectance soil spectra for alternative assessment of soil characteristics in Southern Belgium
Genot, Valérie ULg; Dardenne, Pierre; Bock, Laurent ULg et al

Poster (2012)

In Walloon Region (Southern Belgium), five routine soil laboratories are grouped within a network promoting a better quality in analysis (www.requasud.be). The harmonization of protocols as well as ... [more ▼]

In Walloon Region (Southern Belgium), five routine soil laboratories are grouped within a network promoting a better quality in analysis (www.requasud.be). The harmonization of protocols as well as methodological or technical prospective are realized under scientifically supervision of our research laboratory. In this context, a study was conducted to evaluate the ability of the NIRS to predict some soil properties: CEC, TOC, TN and clay content. The initial models were elaborated upon local PLS regression on set of 1 300 soil samples. The local PLS calibration used allows an accurate prediction of the soil properties and precision of NIRS technique is comparable to reference analytical method [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 detailValorisation de la Carte Numérique des Sols de Wallonie et d’une base de données disponible en analyse de sols, dans le cadre de l’évaluation du risque de pollution des eaux souterraines par les pesticides
Bah, Boubacar Billo ULg; Vanclooster, Marnik; Oger, Robert ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(S2), 709-726

This study shows how the Digital Soil Map of Wallonia and the associated soil database Aardewerk can be combined with the MetaPEARL model to assess the sensitivity of agricultural soils to pesticide ... [more ▼]

This study shows how the Digital Soil Map of Wallonia and the associated soil database Aardewerk can be combined with the MetaPEARL model to assess the sensitivity of agricultural soils to pesticide transfer into underground water tables in Wallonia (Southern Belgium). MetaPEARL is based on an analytical expression which describes the concentration of leached pesticides at the soil profile bottom depending on available data on soil characteristics, climate and pesticide properties. The results show an important soil sensitivity to pesticide transfer with a coefficient of retention on organic matter (Kom) very weak (about 10 dm3.kg-1) or with a relatively high half-life time (DT50 about 60 days). In this case, the pesticide is weakly retained by soil organic matter or slowly degraded and then stays available in the soil and can be quickly leached during rainfalls. In other respects, the pesticide sensitivity to leaching is strongly correlated with soil texture and its organic matter content. It is also observed that the concentration of leached pesticide is strongly depending of the rainfall surplus (water flux into the soil or hydrous balance). A sensitivity analysis has shown that the model is very sensitive to soil thickness, to organic matter content, to the bulk density of the mineral fraction by textural classes and of the organic matter. Therefore, these pedological variables have to be assessed with the highest precision to avoid adding further uncertainty to the predictions obtained. On the basis of the most sensitive soil variables, the analysis of “spatial” uncertainty related to the results delivered by MetaPEARL, due to the consideration of an unique representative value by soil type and by region (deterministic approach), shows that this approach tends to under-estimate the concentration of pesticide leached in the soil. And that compared to the use of a stochastic simulation (probabilistic approach) which takes into account the soil characteristic variability within a given soil type. This stochastic approach allows also the calculation of a more relevant threshold of risk probability (percentile) which can be compared to an imposed standard in view to enhance a sustainable management of natural resources. [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 detailApplication de la spectrométrie proche infrarouge à l'analyse de terre
Genot, Valérie ULg; Colinet, Gilles ULg; Bock, Laurent ULg et al

in Actes des 10èmes rencontres de la fertilisation raisonnée et de l'analyse de terre (2011, November)

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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 detailA Methodology for Sampling Design dedicated to the Evaluation of Effects of Soil Type and Land Use on the Fate of Metallic Trace Elements in Contaminated Soils
Liénard, Amandine ULg; Bock, Laurent ULg; Colinet, Gilles ULg

Poster (2011, July 04)

Contaminated soils may present a risk to human health and the environment. The aim of this study is to evaluate the fate of metallic trace elements (Cd, Pb and Zn) brought to soils from atmospheric ... [more ▼]

Contaminated soils may present a risk to human health and the environment. The aim of this study is to evaluate the fate of metallic trace elements (Cd, Pb and Zn) brought to soils from atmospheric fallouts according to soil type and land use. We have developed a sampling soil strategy in order to both map soil contaminations and assess the effects of soils and land use on the mobility of MTE. [less ▲]

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See detailUn conseil de fumure raisonné - le cas du phosphore
Genot, Valérie ULg; Renneson, Malorie ULg; Bock, Laurent ULg et al

Book published by ASBL REQUASUD - Edition 2011 (2011)

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See detailNear infrared reflectance spectroscopy for estimating soil characteristics valuable in the diagnosis of soil fertility
Genot, Valérie ULg; Colinet, Gilles ULg; Bock, Laurent ULg et al

in Journal of Near Infrared Spectroscopy [=JNRIS] (2011), 19(2), 117-138

Soil fertility diagnostics rely not only upon measurement of available nutrients but also upon the soil’s ability to retain these nutrients. Near-infrared reflectance spectroscopy (NIRS) is a rapid and ... [more ▼]

Soil fertility diagnostics rely not only upon measurement of available nutrients but also upon the soil’s ability to retain these nutrients. Near-infrared reflectance spectroscopy (NIRS) is a rapid and non-destructive analytical technique which allows to simultaneously estimate standard soil characteristics and does not require use of chemicals. Previous studies showed that NIRS could be used in local contexts to predict soil properties. The main goal of our research is to build a methodological framework for the use of NIRS at a more global scale. The specific goals of this study were (i) to identify the best spectra treatment and processing –LOCAL versus GLOBAL regression- methods, (ii) to compare NIRS performances to standard chemical protocols and (iii) to evaluate the ability of NIRS to predict soil total organic carbon (TOC), total Nitrogen (TN), clay content and cationic exchange capacity (CEC) for a wide range of soil conditions. We scanned 1,300 samples representative of main soil types of Wallonia under crop, grassland or forest. Various sample preparations were tested prior to NIRS measurements. The most appropriate options were selected according to ANOVA analysis and multiple means comparisons of the spectra principal components. Fifteen pre-treatments were applied to a calibration set and the prediction accuracy was evaluated for GLOBAL and LOCAL modified partial least square (MPLS) regression models. The LOCAL MPLS calibrations showed very encouraging results for all the studied characteristics. On average, for crop soil samples, the prediction coefficient of variation (CVp) was close to 15% for TOC content, 7% for TN content, and 10% for clay content and CEC. The comparisons of repeatability and reproducibility of both NIRS and standard methods showed that NIRS is as reliable as reference methods. Prediction accuracy and technique repeatability allow the use of NIRS within the framework of the soil fertility evaluation and its replacement of standard protocols. LOCAL MPLS can be applied within global datasets, such as the International global soil spectral library. However, the performance of LOCAL MPLS is linked to the number of similar spectra in the dataset and more standard measurements are needed to characterize the least widespread soils. [less ▲]

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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 detailAgro-pedological Assessment of the Traditional Yuanyang Rice Terraces of Yunnan Province, China
Colinet, Gilles ULg; Koulos, Keiko; Wu, Bozhi et al

in Journal of Resources and Ecology (2011), 2(4), 353-361

As a contribution to a long-term evaluation of the sustainability of agro-ecosystems in the Yuanyang rice terraces, this paper reviews the bio-physical environment of the terraced landscape in a small ... [more ▼]

As a contribution to a long-term evaluation of the sustainability of agro-ecosystems in the Yuanyang rice terraces, this paper reviews the bio-physical environment of the terraced landscape in a small catchment around Qingkou village and assesses soil fertility in the village crop growing area. A soillandscape organization pattern was developed using a geomorphopedological approach. Anthropogenic, climatic and topographic factors were identified as the main soil forming factors. Soil capability and associated edaphic constraints were assessed and the main soil types were identified and classified using FAO protocols. Spatial patterns of soil fertility appear quite homogeneous. Soils are acid and cation exchange capacity and nutrient reserves are generally low. The agro-ecosystem has largely been developed by the Hani population. This agro-ecosystem has succeeded in maintaining a relatively dynamic nutrient circulation system. Current research is focusing on: (i) the evaluation of the representativeness of the studied area compared to the whole terraced system in the Yuanyang terraced landscape; (ii) measurements of nutrients flows at the field scale; (iii) the effects of soil properties on crop yields; and (iv) up-scaling field levels results to larger spatial units. [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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