References of "Tychon, Bernard"
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See detailSuivi de l'état de l'AGRIculture WALlonne par TELédétection (projet SAGRIWATEL)
Tychon, Bernard ULg; Istasse, Alain

Conference (2005, May 11)

Le projet de recherche et développement sur le « Suivi de l’Etat l’Agriculture Wallonne par Télédétection (SAGRIWATEL) » entamé en janvier 2003 est réalisé dans le cadre d’une étroite collaboration entre ... [more ▼]

Le projet de recherche et développement sur le « Suivi de l’Etat l’Agriculture Wallonne par Télédétection (SAGRIWATEL) » entamé en janvier 2003 est réalisé dans le cadre d’une étroite collaboration entre une équipe de scientifiques provenant de différents organismes de recherche wallons (Centre Wallon de Recherches Agronomiques, Université de Liège, Université Catholique de Louvain, Faculté Universitaire des Sciences Agronomiques de Gembloux) et l’Administration Wallonne de l’Agriculture (DGA). Il vise à mettre en place pour l’Administration Wallonne de l’Agriculture des outils de suivi de l’agriculture tant pour ce qui concerne ses activités de production que pour ce qui concerne ses activités en lien avec la protection du milieu (mesures agro-environnementales). Ces outils sont conçus, selon les cas, pour du contrôle, de l’encadrement ou encore pour le suivi global de l’évolution de l’agriculture à l’échelle de la région wallonne. Le système vise à valoriser la base de données du Système Intégré de Gestion et de Contrôle (SIGC) qui est en mesure de fournir des informations pour des applications autres que celles pour lesquelles il a été conçu. En association avec de l’information satellite ou aérienne et des modèles de croissance des cultures une série d’applications concrètes ont été élaborées pour : - la prévision des productions agricoles - la délimitation de zones à stress hydrique - le repérage et l’estimation de surfaces ou de longueurs de bandes enherbées, haies,… - le repérage de la couverture hivernale des sols - le repérage du sens du labour - le suivi des successions culturales - le suivi de la diversité des cultures - l’évolution de la taille des parcelles - … Le système bénéficie de l’apport du SIGC graphique qui fonctionne en Belgique de manière opérationnelle depuis 1997. L’utilisation originale qui est faite du SIGC dans cette étude constitue une nouvelle valorisation de ce système cartographique au départ destiné uniquement à du contrôle des déclarations des agriculteurs. L’approche est intéressante car elle permet un meilleur suivi de l’état de l’agriculture pour l’Administration avec un outil dont elle a la maîtrise, lui permettant de répondre rapidement aux demandes, notamment de l’Europe. En outre, l’outil s’est révélé rapidement opérationnel et adaptable à de nouvelles demandes ce qui constitue un avantage non négligeable quand l’on analyse les fréquentes évolutions de la PAC de ces dernières années. Enfin, l’approche optimise les informations transmises par les agriculteurs lors de leur déclaration PAC, leur évitant des pertes de temps dans des demandes de renseignement répétitives conduisant en quelque sorte à une simplification administrative. L’accès à l’information au sein de la Direction Générale de l’Agriculture se fera via une interface WEB-GIS. Un prototype sera opérationnel dans moins de deux mois. Il est prévu qu’à terme, d’autres Institutions Wallonnes et les agriculteurs wallons euxmêmes puissent bénéficier de cette avancée technologique. [less ▲]

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See detailGeoTraceAgri final project report (GTA)
Debord, Michel; Chauchard, Alain; Tychon, Bernard ULg et al

Report (2005)

Are the universalisation and the globalisation of trade exchanges synonymous with a standardization in which agro-food products uprooted of their soil will no longer be differentiated from manufacturers ... [more ▼]

Are the universalisation and the globalisation of trade exchanges synonymous with a standardization in which agro-food products uprooted of their soil will no longer be differentiated from manufacturers or supermarket brands? Original food products belong to the inheritance of the territories and the consumers are attracted more and more by their authenticity. The GeoTraceAgri project resolutely supports agriculture and the sustainable promotion of the territory as opposed to universalisation which standardizes and moves away those who produce for consumers. Geotraceability aims at associating information of geographical nature with the traditional data of traceability. Farming origin and operations have become factual and verifi able data is available everywhere in the world, thus making it possible to bring additional guarantees to the signs of quality. The GeoTraceAgri (GTA) project largely contributed to the realisation of geotraceability. With the implementation from January 1,2005 of the new Common Agricultural Policy and its regulation imposing on the Member States a single system of declaration, all the agricultural parcels now form part of a European database of geographical references. This new regulation reinforces the basis of the concept of geotraceability, whereas throughout the project it was necessary to defi ne geo-indicators for integrated or crop production with very few geographical data on the farming precedents. The development of the GTA prototype rests on a decentralized architecture and Web services. It was indeed necessary to conceive a system which is readily accessible on Internet for farmers, co-operatives and collectors, and potentially with the administrations which have control responsibilities. In term of acceptability, the potential users realise the potential economic benefi ts of the concept and of the indicators of geotraceability in their plan of exploitation, on the other hand sociological acceptability is less evident which induces the need for communication to make for its adoption. This fi nal report fi nal illustrates the fi rst stage : the GeoTraceAgri partners are continuing their research on the defi nition of an integrated system of geotraceability for the Common agricultural policy and the plan of analysis of the results of GeoTraceAgri should lead to the marketing within two years of an application making it possible to integrate the geo-indicators into management software for the actors of the agro food chain. [less ▲]

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See detailMonitoring of the 2003 summer drought in Belgium with the NDWI applied on spot-vegetation data.
Horion, Stéphanie; Eerens, Herman; Tychon, Bernard ULg et al

in Veroustraete, F.; Bartholomé, E.; Verstraeten, W. W. (Eds.) Proceedings of the 2nd international vegetation user conference. 1998-2004 : 6 years of operational activities. (2005)

The summer 2003 was abnormally hot, sunny and dry. The average temperatures from June to August were the highest ever recorded in the Belgian reference meteorological station of Uccle, but also in other ... [more ▼]

The summer 2003 was abnormally hot, sunny and dry. The average temperatures from June to August were the highest ever recorded in the Belgian reference meteorological station of Uccle, but also in other countries of western and central Europe such as Portugal, Germany, Switzerland and the United Kingdom. Many human activities were affected by these particular climatic conditions, among which agriculture.The Normalized Difference Water Index (NDWI) applied on ten-daily SPOT- VEGETATION imagery is one of the drought indicators which could serve for the localisation of drought affected areas in Belgium. In this paper preliminary results show that detection of dry events is possible using historical averages of NDWI. Relative NDWI images can be used to monitor the development of the summer drought.These images are computed by the weighted difference between the NDWI values during this summer and its value at the same period in a reference year, which corresponds to a normal year in terms of rainfall availability. Analysis of the relation between NDWI and NDVI behaviours show that the green biomass influences the NDWI value especially during the growing season. More accurate study has to be done to individualize the specific NDWI behaviour during dry events. In perspectives, index validation with meteorological parameters and with the Relative Soil Moisture Index, which is an output of the Belgian Crop Growth Monitoring System, will improve this study. [less ▲]

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See detailUse of spot/vegetation in different versions of the European crop growth monitoring system.
Piccard, I.; Eerens, H.; Oger, Robert ULg et al

in Veroustraete, F.; Bartholomé, E.; Verstraeten, W. W. (Eds.) Proceedings of the 2nd international vegetation user conference, 1998-2004 : 6 years of operational activities (2005)

The Crop Growth Monitoring System (CGMS) is a GIS-application, developed and operated since 1989 by the MARS-unit of the EU Joint Research Centre. The primary objective is the timely forecasting of the ... [more ▼]

The Crop Growth Monitoring System (CGMS) is a GIS-application, developed and operated since 1989 by the MARS-unit of the EU Joint Research Centre. The primary objective is the timely forecasting of the yields of the main crops on the Pan-European continent.To reach this goal, CGMS combines all available (historical and actual) resources: official crop statistics, daily meteorological data, specific crop and soil parameters, the predictions of the (spatialized) crop growth model WOFOST, and the 10-daily composite images of NOAA-AVHRR and SPOT-VEGETATION. In recent years CGMS has been implemented in different regions of the world, also beyond Europe. This paper gives a brief overview of some of these applications, with emphasis on the remote sensing component, especially SPOT-VEGETATION. In 2000, JRC outsourced the practical operation of CGMS to a consortium composed by Alterra (main tasks, agrometeorological model), MeteoConsult (meteo-provider) and VITO (remote sensing). MARS-STAT delivers the European yield forecasts to the EU statistical office EUROSTAT, in view of the follow-up of market prices and the achievement of the CAP-regulations. MARS-FOOD particularly deals with important food producing areas (Russia, Mercosur) and famine-threatened zones in Africa (IGAD-zone). The long-term goal is to steadily fill the actual data gaps (crop areas, parameters, meteo,…) so that, in time, the full CGMS (incl. the model) could be applied on these areas (or even globally). Specific versions of CGMS emerged in different countries (Finland, Spain, Kazakhstan,…), running with more detailed input data. One example is the so-called B-CGMS which has been operating since 1998 on behalf of the Belgian ministry of agriculture, in a collaboration between ULg-Arlon, CRA-Gembloux and VITO. Since 2002, the B-CGMS group publishes monthly bulletins with forecasts on crop yields, areas and productions. The areas are delivered by the IACS (annually updated GIS of all crop parcels, maintained for the EU-CAP). Together with local partners, the same Belgian group is now implementing CGMS in China’s north-eastern province Heilongjiang, part of former Manchuria and China’s main producer of soybean, maize and singlecropped rice. Special attention is being paid to the steady drying-out of this region, which 50 years ago was mainly covered by wetlands and forests. Climate change and mismanaged paddy irrigation are leading to a dramatic lowering of the water tables. Technically, this paper will focus on the main deliverables derived from NOAA- AVHRR and SPOT- VEGETATION. This includes pre/post-processing, extraction of biophysical vegetation state parameters (NDVI, SAVI, fAPAR, Dry Matter Productivity), differences with regard to the historical year (VCI, VPI, etc.), quicklooks, etc. Of most concern however is the “ unmixing” approach, which attempts to conform the remote sensing data (image format, 1 km-pixels, different crops mixed) to the CGMS-standards (databases with district/crop as spatial/thematic units). If the low/medium resolution sensors (AVHRR, VEGETATION, MODIS, MERIS,..) want to maintain their role in this agricultural domain, this problem has to be solved. Otherwise, the floor is open for new, revolutionary initiatives such as DMC (Disaster Monitoring Constellation: daily global coverage at 32m resolution). [less ▲]

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See detailAnalyse climatique de la région de Gouré, Niger oriental : récentes modifications et impacts environnementaux
Ozer, Pierre ULg; Bodart, Catherine ULg; Tychon, Bernard ULg

in Cybergeo : Revue Européenne de Géographie = Cybergeo - European Journal of Geography (2005)

Since the late 1960s, the Sahel is affected by a dramatic drought. This article analyses climatic variations recorded in the Gouré area, eastern Niger, between 1936 and 2003. It appears that the drought ... [more ▼]

Since the late 1960s, the Sahel is affected by a dramatic drought. This article analyses climatic variations recorded in the Gouré area, eastern Niger, between 1936 and 2003. It appears that the drought ended in the late 1980s. However, the rainfall increase did not lead to an extension of the length of the rainy season. The study of the wind shows that correct data were recorded during the two first years of the station of Gouré (1984 and 1985). Afterwards, wind speed was entached by errors and did not report since 1997. The situation is alarming as we know that neighbouring stations meet the same problems and that no synoptic station currently reports wind values in eastern Niger. However, based on wind speed and deflation data recorded in 1984, a threshold wind speed of 7 m/s was determined in Gouré. Finally, from measurements of horizontal visibility reduced by mineral dust, our results suggest that air quality is reduced because of the high frequency of wind erosion. The confrontation of our results with recent environmental studies in that region show that the end of the drought did not lead to any landscape improvement. Increasing human pressure tends to be the main driving factor of land degradation. [less ▲]

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See detailCan hyperspectral techniques improve estimates of carbon stocks in agricultural soils ?
Stevens, A.; van Wesemael, B.; Touré, Souleymane et al

in Proceedings of the Airborne imaging spectroscopy workshop : Belspo, Bruges 8 octobre 2004 (2004, October 08)

Soil organic carbon (SOC) represents one of the major pools in the global carbon cycle. However, fluxes of CO2 from soils into the atmosphere by respiration or inversely sequestration of CO2 through ... [more ▼]

Soil organic carbon (SOC) represents one of the major pools in the global carbon cycle. However, fluxes of CO2 from soils into the atmosphere by respiration or inversely sequestration of CO2 through photosynthesis and subsequent immobilisation in the form of humus are difficult to quantify. In principle changes in SOC stock over time reflect CO2 fluxes. The detection of these stock changes, however, require intensive sampling mainly due to the large spatial variability of SOC both within individual fields and larger units with similar soils and land use. The aim of this paper is to evaluate the potential of airborne-hyperspectral techniques using a CASI sensor and hand held Near Infrared Spectroscopy (NIRS) with an ASD spectrometer to conduct SOC inventories of individual parcels. During a field campaign in the Belgian Ardennes during Octobre 2003, more than 120 sites on a regular grid within 13 freshly ploughed fields were selected. At these sites, field spectra of the bare soil have been measured and samples from the topsoil were taken. SOC content (Walkley and Black), soil moisture and bulk density of these samples have been determined. As a first step, the soil reflectance has been transformed (log (1/R), Savitsky-Golay smoothing and derivative, gap derivative, moving average) in order to filter the spectral responses and to eliminate noise. Then, we used both stepwise and partial least square (PLS) regression analysis to relate these spectra to measured SOC contents. Regression models performed much better when the data were divided in two sub-groups representing different moisture conditions of the soil surface. These statistical model calibrations were validated on an independent data set. Standard Error of Prediction (SEP) ranged from 0.19 to 0.24 % carbon for the field spectra determined using the ASD depending on soil moisture of the surface layer. This is a little bit more than the reproducibility error inherent to the Walkley and Black analysis. Airborne CASI techniques performed less well mainly due to the narrow spectral range. Tests on airborne CASI+SASI hyperspectral data from a previous field campaign [1] showed better results. Overall, low bias allowed the use of spectral techniques to estimate population means with a high confidence level. The spectral techniques have a strong potential in determining changes in carbon tock change studies. The large within field variability of SOC content precludes the assessment, using conventional soil sampling, of SOC changes as a result of management (1 t C ha-1 yr-1) over a reasonable time period (5 years). Depending on the variance of the SOC content measured in the field ( 2 = 11-166 t C ha-1), we need 16-210 samples to detect a change. Since this number of samples is rarely available for individual fields, conventional sampling methods can only be used for larger spatial units containing many fields. In contrast, the airborne-hyperspectral technique and portable NIRS are able to supply these large amounts of data, and can thus improve the accuracy of SOC stock assessments of individual fields. This in turn will result in a smaller detection limit of SOC stock changes. [less ▲]

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See detailAirborne hyperspectral measurements and superficial soil organic matter
Touré, Souleymane; Tychon, Bernard ULg

in Proceedings of the Airborne Imaging Spectroscopy Workshop (2004, October 08)

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was ... [more ▼]

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was based on a forward stepwise multiple linear regression analysis linking soil organic matter and hyperspectral data from the CASI-2 (Compact Spectrographic Imager-2) airborne sensor working in the visible and near infrared domain. The results were validated successfully from an independent set of sampling points. However, disturbing factors effects are shown on the relationship between soil organic matter and spectral reflectance. It is concluded that the hyperspectral remote sensing approach is promising for soil organic matter prediction but it will require more study to better take account on the disturbing factors affecting the relationship. [less ▲]

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See detailBulletin agrométéorologique - Août 2004
Tychon, Bernard ULg; Ozer, Pierre ULg; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(5), 1-4

Le mois d’août a été caractérisé par des précipitations, des vitesses de vent et une humidité anormalement élevées. Les valeurs de rayonnement étaient par contre anormalement faibles. Les rendements ... [more ▼]

Le mois d’août a été caractérisé par des précipitations, des vitesses de vent et une humidité anormalement élevées. Les valeurs de rayonnement étaient par contre anormalement faibles. Les rendements prévus pour le maïs fourrager sont légèrement inférieurs à ceux observés au cours des cinq années antérieures. Par contre, concernant la betterave sucrière et la pomme de terre mi-hâtive, la tendance est inverse avec des estimations globalement supérieures à la moyenne des cinq dernières années. [less ▲]

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See detailBulletin agrométéorologique - Juillet 2004
Tychon, Bernard ULg; Ozer, Pierre ULg; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(4), 1-4

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See detailBulletin agrométéorologique - Juin 2004
Tychon, Bernard ULg; Ozer, Pierre ULg; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(3), 1-5

Les paramètres climatiques du mois de juin furent tous proches de la moyenne, exception faite de l'ensoleillement qui fut largement déficitaire sur l’est du pays. La situation des céréales d’hiver et de ... [more ▼]

Les paramètres climatiques du mois de juin furent tous proches de la moyenne, exception faite de l'ensoleillement qui fut largement déficitaire sur l’est du pays. La situation des céréales d’hiver et de la pomme de terre est globalement favorable laissant entrevoir des rendements généralement supérieurs à ceux de 2003. Par contre, les prévisions relatives au maïs fourrager et à la betterave sucrière montrent que ces cultures pourraient connaître, au niveau national, une légère baisse par rapport à l’année passée. [less ▲]

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See detailBulletin agrométéorologique - Mai 2004
Tychon, Bernard ULg; Ozer, Pierre ULg; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(2), 1-5

Les températures et l'ensoleillement du mois de mai furent légèrement inférieurs à la moyenne. En revanche, les précipitations déficitaires furent généralisées et les périodes sans pluie ont atteint près ... [more ▼]

Les températures et l'ensoleillement du mois de mai furent légèrement inférieurs à la moyenne. En revanche, les précipitations déficitaires furent généralisées et les périodes sans pluie ont atteint près de trois semaines en certaines régions. La situation des cultures est globalement favorable laissant entrevoir des rendements généralement semblables, voire supérieurs à ceux de 2003. [less ▲]

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See detailBulletin agrométéorologique - Avril 2004
Tychon, Bernard ULg; Ozer, Pierre ULg; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(1), 1-4

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See detailUse of remote sensing imagery for geotraceability in agriculture
Buffet, Dominique; Oger, Robert ULg; Tychon, Bernard ULg

Conference (2004, May 06)

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See detailAnalyse de la campagne agricole 2003 en terme de stress hydrique
De Longueville, Florence ULg; Horion, Stéphanie ULg; Tychon, Bernard ULg et al

in Bulletin de la Société Géographique de Liège (2004), 44

This article presents the evaluation of the crop water stress in 2003 using the Belgian Crop Growth Monitoring System (B-CGMS). The indicator used is the Relative Soil Moisture Index (RSMI), and is based ... [more ▼]

This article presents the evaluation of the crop water stress in 2003 using the Belgian Crop Growth Monitoring System (B-CGMS). The indicator used is the Relative Soil Moisture Index (RSMI), and is based on a calculation integrating soil moisture data. This index shows the differences between needed and effectively available soil water for different crop types. It is one of the outputs of the B-CGMS agrometeorological model. Based on a fixed threshold, days affected by water stress have been identified and computed for specific periods during which lack of soil water is likely to have dramatic impacts on crop production. The cumulative number of days affected by water stress indicator has then been integrated into a GIS to spatially represent the situation of winter wheat and maize during the 2003 crop season. Results suggest that only maize was affected by the water stress in northern and southern Belgium. In the latter area, the lack of water at key periods provoked a yield reduction ranging between 2 and 50%. [less ▲]

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See detailL’enseignement en gestion des risques naturels.
Ozer, Pierre ULg; Tychon, Bernard ULg; Ozer, André ULg et al

in Demarée, Gaston; De Dapper, Morgan; Alexandre, Jean (Eds.) Tropical Climatology, Meteorology and Hydrology: Climate-related risk analysis and sustainable development in tropical areas. (2004)

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See detailMonitoring drought stress in north-eastern China by means of rainfall data and diachrone indices derived from Pathfinder AVHRR-imagery.
Ozer, Pierre ULg; Tychon, Bernard ULg; Eerens, Herman

in Smits, Paul; Bruzzone, Lorenzo (Eds.) Analysis of Multi-Temporal Remote Sensing Images (2004)

For climatic stress detection and monitoring in the Heilongjiang Province, north-eastem China, an indicator on the interannual vegetation state was extracted from the AVHRR Pathfinder image set (1981-2000 ... [more ▼]

For climatic stress detection and monitoring in the Heilongjiang Province, north-eastem China, an indicator on the interannual vegetation state was extracted from the AVHRR Pathfinder image set (1981-2000) and compared to the rainfall variations over the growing season (June to August). The results show that the vegetation status does not closely depend on rainfall variations in this region. Temperatures, which showed a rapid augmentation in the northern high latitudes since the early 1980s, seem to be a more crucial limiting factor for vegetation growth. Rapid land cover change and large natural disasters are also likely to impact the relationship between rainfall and vegetation. [less ▲]

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