References of "Djaby, Bakary"
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See detailThe Agrometeorological crop yield forecasting System of Armenia - User Manual - December 2013
Tychon, Bernard ULg; Denis, Antoine ULg; Djaby, Bakary ULg et al

Learning material (2013)

« This document was produced under the Agrometeorological component of the “EC/FAO Programme on Information Systems to Improve Food Security Decision-Making in ENP East Area” in Armenia. The objective of ... [more ▼]

« This document was produced under the Agrometeorological component of the “EC/FAO Programme on Information Systems to Improve Food Security Decision-Making in ENP East Area” in Armenia. The objective of the Programme in Armenia is to support government’s priorities to reduce food insecurity and poverty by improving the quality and sharing of information across institutions, and promoting evidence-based analyses and assessments. This User Manual of Crop Yield Forecasting System used in Armenia may be used as a reference document for the future calculation of yield forecasts that HYDROMET will use in the coming years. [less ▲]

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See detailPerformance assessment of the FAO AquaCrop model for irrigated cabbage on farmer plots in a semi-arid environment
Wellens, Joost ULg; Raes, Dirk; Traore, Farid et al

in Agricultural Water Management (2013), 127

Small-scale irrigation initiatives are expanding rapidly in Burkina Faso. However, in many cases optimal yields are not being obtained despite the available water and the required nutrient applications ... [more ▼]

Small-scale irrigation initiatives are expanding rapidly in Burkina Faso. However, in many cases optimal yields are not being obtained despite the available water and the required nutrient applications. Local stakeholders need an easy-to-use decision-support tool to assess irrigation water use and its impact on yield. In this study, a water-driven crop model, AquaCrop, developed by FAO, was adapted for cabbage (Brassica oleracea L.) using a limited dataset and leave-one-out cross-validation (LOOCV). The experiment was conducted in south-western Burkina Faso on small irrigated farmer plots, where optimal managerial conditions could not always be guaranteed. Statistical indicators – normalized root mean square error (nRMSE) and index of agreement (d) – suggested that the model is very reliable for simulating cabbage biomass yield and soil water content (low nRMSE and d-index near 1). The relationship between observed and simulated yield produced a d-index of 0.99 and an nRMSE of 1.39% (or 0.59 ton/ha). The comparison between observed and modeled soil water content gave a d-index of 0.90 and an nRMSE of 4.38% (or 9.13 mm). Also of interest was the indirect link between plant density and yield via maximum canopy cover, which can considerably simplify yield estimation. It was concluded that AquaCrop was a very useful tool for enabling local end-users to evaluate and optimize cabbage yield and irrigation water use. [less ▲]

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See detailÉVOLUTION CLIMATIQUE, PERCEPTION ET ADAPTATION DES COMMUNAUTES RURALES DU PLATEAU D’ABOMEY (BENIN)
Ozer, Pierre ULg; Hountondji, Yvon-Carmen; Ahomadegbe, Mathias et al

in Boko, Michel; Vissin, Expédit W.; Afouda, Fulgence (Eds.) CLIMAT, AGRICULTURE & RESSOURCES EN EAU d'hier à demain (2013, September)

West Africa is extremely vulnerable to climate change. This paper first analyses recent trends in extreme rainfall and temperatures recorded at six synoptic stations in Benin. Results show that rainfall ... [more ▼]

West Africa is extremely vulnerable to climate change. This paper first analyses recent trends in extreme rainfall and temperatures recorded at six synoptic stations in Benin. Results show that rainfall is declining while temperatures are increasing significantly. Cold nights (1st TMin percentile) are decreasing very significantly while hot days (99th TMax percentile) are increasing very significantly. No trend is observed in the frequency of extreme rainfall events. Then, rural populations of the plateau of Abomey were interviewed about their perception of climatic risks. They highlighted that major risks are spatiotemporal rain variability and rainfall shortage / excess (drought / flood), strong winds, and excessive temperature. Confronted with these hazards, local farmers are developing on their own endogenous strategies, which are mostly not rational and far from solving climatic hazards in a sustainable way. More detailed studies are needed in order to identify together with these communities pragmatic and sustainable adaptive options. [less ▲]

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See detailEVALUATION DES EMISSIONS DE METHANE IMPUTABLES AU SECTEUR AGRICOLE EN AFRIQUE DE L’OUEST (1961-2050)
Djaby, Bakary ULg; Ozer, Pierre ULg

in Boko, Michel; Vissin, Expédit W.; Afouda, Fulgence (Eds.) CLIMAT, AGRICULTURE & RESSOURCES EN EAU d'hier à demain (2013, September)

The objective of this study is to review the evolution of methane (CH4) emissions related to agriculture in West Africa over the last fifty years (1961-2010). The main agricultural sources of CH4 are ... [more ▼]

The objective of this study is to review the evolution of methane (CH4) emissions related to agriculture in West Africa over the last fifty years (1961-2010). The main agricultural sources of CH4 are ruminants (enteric fermentation) and rice production (anaerobic decomposition). To do this, we used the FAO statistics for both rice production and livestock. It appears that CH4 emissions are regionally rising although presenting large differences between the Sahelian countries and those of the Gulf of Guinea. Indeed, the countries bordering the Sahara seem to take profit of improving rainfall over the past two decades to increase livestock. On the contrary, wetter countries increase rice development. A close relationship is found between the human population and CH4 emissions from the agricultural sector. Yet, human population increase projected by 2050 is questionable, particularly in relation to the margin of CH4 emissions increase in West Africa. [less ▲]

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See detailSpatial Distribution of Calibrated WOFOST Parameters and Their Influence on the Performances of a Regional Yield Forecasting System
Djaby, Bakary ULg; Louis, Kouadio; El Jarroudi, Moussa ULg et al

in Sustainable Agriculture Research (2013)

We investigate in this study (i) a redefinition of crop variety zonations at a spatial scale of 10x10 km, and (ii) the influence of recalibrated crop parameters on regional yield forecasting of winter ... [more ▼]

We investigate in this study (i) a redefinition of crop variety zonations at a spatial scale of 10x10 km, and (ii) the influence of recalibrated crop parameters on regional yield forecasting of winter wheat and grain maize in western Europe. The baseline zonation and initial crop parameter set was derived from the operational European crop growth monitoring system (CGMS) which involves the agrometeorological model WOFOST. Air temperature data from 325 weather stations over the 1992-2007 period were used to define new zonations in a 300 x 300 km test site. Two parameters which influenced mostly the phenological development stages (i.e. TSUM1 and TSUM2, the effective air temperature sums from emergence to anthesis, and from anthesis to maturity, respectively) were chosen and calibrated. The CGMS was finally run based on these new recalibrated parameters and simulated crop status indicators were compared with official statistics over the 2000-2007 period. Our results showed that the days of anthesis and maturity were simulated with coefficients of determination (R2) ranging from 0.22 to 0.87 for both crops over the study site. A qualitative assessment of maximum leaf area index and harvest index also revealed a more consistent spatial pattern than the initial zonation in the simulation results. Finally, recalibrated TSUM1 and TSUM2 led to improved relationships between official yield and simulated crop indicators (significant R2 in 17 out of 28 and in 14 out of 59 NUTS3 regions with respect to the best predictor for grain maize and winter wheat, respectively). [less ▲]

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See detailEstimating crop-specific evapotranspiration using remote-sensing imagery at various spatial resolutions for improving crop growth modelling
Sepulcre-Cantó, Guadalupe; Gellens-Meulenberghs, Françoise; Arboleda, Alirio et al

in International Journal of Remote Sensing (2013)

By governing water transfer between vegetation and atmosphere, evapotranspiration (ET) can have a strong influence on crop yields. An estimation of ET from remote sensing is proposed by the EUMETSAT ... [more ▼]

By governing water transfer between vegetation and atmosphere, evapotranspiration (ET) can have a strong influence on crop yields. An estimation of ET from remote sensing is proposed by the EUMETSAT ‘Satellite Application Facility’ (SAF) on Land Surface Analysis (LSA). This ET product is obtained operationally every 30 min using a simplified SVAT scheme that uses, as input, a combination of remotely sensed data and atmospheric model outputs. The standard operational mode uses other LSA-SAF products coming from SEVIRI imagery (the albedo, the downwelling surface shortwave flux, and the downwelling surface longwave flux), meteorological data, and the ECOCLIMAP database to identify and characterize the land cover. With the overall objective of adapting this ET product to crop growth monitoring necessities, this study focused first on improving the ET product by integrating crop-specific information from high and medium spatial resolution remote-sensing data. A Landsat (30 m)-based crop type classification is used to identify areas where the target crop, winter wheat, is located and where crop-specific Moderate Resolution Imaging Spectroradiometer (MODIS) (250 m) time series of green area index (GAI) can be extracted. The SVAT model was run for 1 year (2007) over a study area covering Belgium and part of France using this supplementary information. Results were compared to those obtained using the standard operational mode. ET results were also compared with ground truth data measured in an eddy covariance station. Furthermore, transpiration and potential transpiration maps were retrieved and compared with those produced using the Crop Growth Monitoring System (CGMS), which is run operationally by the European Commission’s Joint Research Centre to produce in-season forecast of major European crops. The potential of using ET obtained from remote sensing to improve crop growth modelling in such a framework is studied and discussed. Finally, the use of the ET product is also explored by integrating it in a simpler modelling approach based on light-use efficiency. The Carnegie–Ames–Stanford Approach (CASA) agroecosystem model was therefore applied to obtain net primary production, dry matter productivity, and crop yield using only LSA-SAF products. The values of yield were compared with those obtained using CGMS, and the dry matter productivity values with those produced at the Flemish Institute for Technological Research (VITO). Results showed the potential of using this simplified remote-sensing method for crop monitoring. [less ▲]

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See detailImportance of a Well-distributed Frequency of Measurements in the Senescence Monitoring of Winter Wheat and Yield Estimates
Kouadio, Louis; Djaby, Bakary ULg; El Jarroudi, Moussa ULg et al

in Journal of Agricultural Science and Technology (2012), 2

Theoretical frequencies of green area index (GAI) measurements were assessed in order to bring out the optimum frequencies for the monitoring of the senescence of winter wheat as well as the relationships ... [more ▼]

Theoretical frequencies of green area index (GAI) measurements were assessed in order to bring out the optimum frequencies for the monitoring of the senescence of winter wheat as well as the relationships between metrics which could be derived and the final grain yield. Several profiles of GAI decreasing curves were elaborated based on field measurements. Two functions, usually employed in green leaf area decreasing curves fitting (i.e., modified Gompertz and logistic functions) were then used to characterize the senescence phase and to calculate their metrics. These analyses showed that the two curve fitting functions satisfactorily described the senescence phase on frequencies of four to six GAI measurements, well distributed throughout a period of 30-35 days. The regression-based modeling showed that those involving metrics from logistic function (i.e., maximum value of GAI, green area duration and senescent rate) were more suitable than that of the modified Gompertz function for wheat yield estimates. Such results could be useful for studies at larger scales (involving remote sensing airplane or satellite data) and focused on the senescence in terms of optimum number of measurements and frequencies for developing models for yield estimates. [less ▲]

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See detailCinétique de décroissance de la surface verte et estimation du rendement du blé d’hiver
Kouadio, Amani Louis ULg; Djaby, Bakary ULg; Grégory, Duveiller et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 179-191

A large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. However, the current development of models for wheat yield forecasting ... [more ▼]

A large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. However, the current development of models for wheat yield forecasting does not always reflect the inclusion of the loss of valuable green area and its relation to biotic and abiotic processes in production situation. In this study the senescence phase of winter wheat (Triticum aestivum L.) is monitored through the GAI (Green Area Index), calculated from digital hemispherical photography taken over plots in Belgium, Grand-Duchy of Luxembourg and France. Two curve-fitting functions (modified Gompertz and modified logistic) are used to describe the senescence phase. Metrics derived from these functions and characterizing this phase (i.e. the maximum value of GAI, the senescence rate and the time taken to reach either 37% or 50% of the green surface in the senescent phase) are related to final grain yields. The regression-based models calculated with these metrics showed that final yield could be estimated with a coefficient of determination of 0,83 and a RMSE of 0,48 t.ha-1. Such simple models may be considered as a first yield estimates that may be performed in order to provide a better integrated yield assessment in operational systems. Indeed, estimation of cereal-crop production, particularly wheat, is considered as a priority in most crop research programs due to the relevance of food grain to world agricultural production. [less ▲]

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See detailEstimating regional wheat yield from the shape of decreasing curves of green area index temporal profiles retrieved from MODIS data
Kouadio, Amani Louis ULg; Duveiller, Gregory; Djaby, Bakary ULg et al

in International Journal of Applied Earth Observation and Geoinformation (2012), 18

Earth observation data, owing to their synoptic, timely and repetitive coverage, have been recognized as a valuable tool for crop monitoring at different levels. At the field level, the close correlation ... [more ▼]

Earth observation data, owing to their synoptic, timely and repetitive coverage, have been recognized as a valuable tool for crop monitoring at different levels. At the field level, the close correlation between green leaf area (GLA) during maturation and grain yield in wheat revealed that the onset and rate of senescence appeared to be important factors for determining wheat grain yield. Our study sought to explore a simple approach for wheat yield forecasting at the regional level, based on metrics derived from the senescence phase of the green area index (GAI) retrieved from remote sensing data. This study took advantage of recent methodological improvements in which imagery with high revisit frequency but coarse spatial resolution can be exploited to derive crop-specific GAI time series by selecting pixels whose ground-projected instantaneous field of view is dominated by the target crop: winter wheat. A logistic function was used to characterize the GAI senescence phase and derive the metrics of this phase. Four regression-based models involving these metrics (i.e., the maximum GAI value, the senescence date and the thermal time taken to reach 50% of the green surface in the senescent phase) were related to official wheat yield data. The performances of such models at this regional scale showed that final yield could be estimated with an RMSE of 0.57 ton ha−1, representing about 7% as relative RMSE. Such an approach may be considered as a first yield estimate that could be performed in order to provide better integrated yield assessments in operational systems. [less ▲]

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See detailImages hémisphériques et leur analyse pour prévoir le rendement du blé d’hiver. Comment la phase de décroissance de la surface verte de la plante nous renseigne-t-elle sur le rendement final ?
Kouadio, Amani Louis ULg; Djaby, Bakary ULg; Giraud, Frédéric et al

in Phytoma : La Défense des Végétaux (2011), 648

The prediction of cereal-crop yield is considered as a priority in most crop research programmes due to the relevance of food grain to feeding the world population. Today, a large number of ... [more ▼]

The prediction of cereal-crop yield is considered as a priority in most crop research programmes due to the relevance of food grain to feeding the world population. Today, a large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. But, currently the development of wheat yield forecasting models in conventional operational systems do not reflect the loss of active green leaf area and its relation to biotic and abiotic processes implicated in the crop production situation. In 2009 a large field campaign in the Grand-Duchy of Luxembourg was realized to assess the validity of leaf-green-area approach to further improve yield prediction. Hemispherical photography were taken on winter wheat fields during the crop cycle, preferentially from inflorescence emergence to maturity. The variable of interest, the Green Area Index (GAI), was retrieved after image analyses using the CAN-EYE software. The regression-based models calculated with metrics derived from the decreasing curves of GAI showed that final yield could be better estimated with satisfactory precision: range of the coefficient of determination (R²) varies from 0.73 to 0.86 and RMSE (root mean square error) is varying between 0.43 and 0.56 t/ha. The validation of such approach at the scale of an agricultural zone or region is currently under progress, by using green area index temporal profiles and information on the phenology of winter wheat. Such simple models may be considered as a first step towards yield estimation that may be completed by other agrometeorological models in order to provide a better integrated yield assessment. [less ▲]

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See detailLes systèmes agropastoraux :viabilité et adaptation aux risques climatiques
Djaby, Bakary ULg

Scientific conference (2010, November 04)

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See detailBulletin agrométéorologique - Situation au 1er septembre 2010
Tychon, Bernard ULg; Djaby, Bakary ULg; Denis, Antoine ULg et al

in Bulletin Agrométéorologique (2010), 8(4), 1-4

La période d’avril à août 2010 fut marquée par une forte alternance de périodes sèches et humides avec des épisodes froids succédant à des vagues de chaleur. La période sèche de mi-juin à mi-juillet fut ... [more ▼]

La période d’avril à août 2010 fut marquée par une forte alternance de périodes sèches et humides avec des épisodes froids succédant à des vagues de chaleur. La période sèche de mi-juin à mi-juillet fut particulièrement remarquable et la fin de cette période s’est accompagnée de températures très élevées accentuant encore les besoins en eau des plantes. Les cultures à système racinaire superficiel ou situées dans des terrains peu profond ont largement souffert de cette période. Cependant le mois d’août très pluvieux a permis à la plupart des cultures de printemps de récupérer leur retard de croissance. Les rendements prévus par nos modèles sont bons pour les cultures de betterave sucrière, pomme de terre et maïs. [less ▲]

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See detailWheat Yield Estimates at NUTS-3 level using MODIS data: an approach based on the decreasing curves of green area index temporal profiles
Kouadio, Amani Louis ULg; Duveiller, Gregory; Djaby, Bakary ULg et al

in Cawkwell, Fiona (Ed.) Proceedings of RSPSoc2010 Annual Conference. 1st-3rd September 2010, Cork, Ireland (Nottingham: RSPSoc) (2010, September)

Wheat is the most widely-grown food crop in the world and the most important cereal crop traded on international markets. An early prediction of its yield prior to harvest at regional, national and ... [more ▼]

Wheat is the most widely-grown food crop in the world and the most important cereal crop traded on international markets. An early prediction of its yield prior to harvest at regional, national and international scales can play a crucial role in global markets, policy and decision making. Many models for yield forecasting are available with varying levels of complexity and empiricism. The use of remote sensing technology for monitoring crop condition and predicting crop yields at regional scales have been studied extensively during these last decades. Earth observation data, owing to their synoptic, timely and repetitive coverage, have been recognized as a valuable tool for yield and production forecasting. At field level, studies on crop breeding showed that a close correlation exists between green leaf area during maturation and grain yield in wheat. Thus, the onset and rate of senescence appeared as important factors for determining grain yield of this crop. The aim of this research is to explore a simplified approach for wheat yield forecasting at the European NUTS-3 administrative level, based on metrics derived from the senescence phase of green area index (GAI) estimated from remote sensing data. This study takes advantage of considerable recent improvements in sensor technology and data availability through the opportunity of applying medium/coarse spatial resolution data for deriving crop specific GAI time series by selecting pixels whose ground-projected instantaneous field of view is constituted by a high cover fraction of winter wheat. This approach is tested on 2 crop growing season over a 300 by 300 km study site comprising Belgium and northern France within the framework of the GLOBAM (GLObal Agricultural Monitoring systems by integration of earth observation and modelling techniques) project. The validation of such an approach will involve the comparison with official wheat yield data at NUTS-3 level. [less ▲]

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See detailModélisation spatiale des flux organiques et minéraux assurant la productivité durable des agroécosystèmes culture-élevage dans le sahel nigérien
Djaby, Bakary ULg

Doctoral thesis (2010)

Agriculture (including crop and livestock) employs more than 80% of the work force in semi-arid regions of West Africa and provide most of the food requirements and incomes. In most developing countries ... [more ▼]

Agriculture (including crop and livestock) employs more than 80% of the work force in semi-arid regions of West Africa and provide most of the food requirements and incomes. In most developing countries, soil nutrient depletion is a major issue for soil degradation. Crop-livestock integration is an effective means by which nutrients can be rapidly recycled within and between farms. In West Niger, where mixed farming systems dominate, livestock's role in recycling organic matter and mineral nutrients (nitrogen, phosphorus and potassium) must be better assessed to increase production and ensure sustainable food security. Nutrient flows through forage uptake and excretion deposit by grazing livestock must be assessed at a wider scale than the farm. Organic matter and nutrients balance and fluxes were used as measurable criteria for sustainable agriculture production. This research focuses on these indicators assessments at farm, land use unit and village level. This study was conducted in three agropastoral territories in the Fakara region of western Niger (Dantiandou District) that lies between the Niger River to the west and the Dallol Boboye (Bosso), a fossil valley tributary of the Niger, to the east. The area has homogeneous geological characteristics and rainfall conditions, but land use history, human and animal population density and cropping intensity vary within the region. 461 farms were concerned. In the mixed crop-livestock systems, the duality of the spatial organization, crop management at field level and livestock management with communal rangeland is a major issue for nutrients balance and fertility management modeling. Two models were then used to assess flows and nutrients balances. The NUTMON Toolbox developed by Dutch researchers is used to assess agricultural fluxes at farm parcels level. Spatial modeling was done with NUTPAST, a GIS tool developed in this thesis framework to assess livestock intake and excretion fluxes at land use scale. This tool takes into account the spatiotemporal patterns of vegetation as well as livestock seasonal variation. Quantile regression analysis and multinomial polytomous logistic regression modeling was used to assess soil fertility depletion risk indicator based on farm agriculture viability variables and nutrients partial balance. The results obtained show a less negative partial nutrients balance than in previous studies when the livestock spatio-temporal effect is taken into account. The results bring functional improvement and analytical evaluation of flows and partial nutrients balance calculation, while taking into account the functions of livestock in the organic matter recycling. The overall partial balance of N, P, K are 0.3 ± 0.6, 1.2 ± 0.2, 0.9 ± 0.5 kg/ha. The review highlighted a wide disparity between farms which show a strongly positive balance among livestock owners and negative balance among Fakara small farmers with few land and livestock endowments. Owning animals allows some households to maintain soil fertility by capturing and mobilizing soil nutrients. Risk indicators, based on land pressure indicator at 3x3 km geographic grid level, livestock endowments and land per capita reveal that despite a slow intensification, the trend for a risk of relative depletion of soil fertility is very high. This trend may compromise the sahelian agriculture sustainability. The problems of unequal benefit from communal resources remain a big issue of the sahelian agriculture. With increasing pressure on land, it is necessary to look beyond the traditional free range communal grazing systems to more intensive alternatives and stronger land tenure policies. [less ▲]

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See detailBulletin agrométéorologique - Situation au 30 juin 2010
Tychon, Bernard ULg; Djaby, Bakary ULg; Denis, Antoine ULg et al

in Bulletin Agrométéorologique (2010), 8(2), 1-6

A la fin du mois de juin, les conditions météorologiques peuvent être qualifiées de globalement bonnes sur la plus grande partie du territoire belge. De bons rendements sont annoncés sans toutefois ... [more ▼]

A la fin du mois de juin, les conditions météorologiques peuvent être qualifiées de globalement bonnes sur la plus grande partie du territoire belge. De bons rendements sont annoncés sans toutefois atteindre les rendements exceptionnels comme ceux du blé de l’an dernier. Les analyses spatiales dérivées de la télédétection confirment cette tendance favorable tout en indiquant une hétérogénéité importante dans certaines régions du pays qui peut être mise sur le compte de précipitations orageuses localisées. Les conditions climatiques des prochaines semaines seront déterminantes pour conserver tous les bons potentiels de rendement des cultures et éviter que la situation ne se dégrade pour les zones à plus faible potentiel. [less ▲]

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See detailBulletin agrométéorologique - Situation au 30 avril 2010
Tychon, Bernard ULg; Djaby, Bakary ULg; Denis, Antoine ULg et al

in Bulletin Agrométéorologique (2010), 8(1), 1-4

La période hivernale fut caractérisée par des températures inférieures aux moyennes des 20 dernières années. L’hiver fut également marqué par d’abondantes chutes de neige. Les sommes de températures ... [more ▼]

La période hivernale fut caractérisée par des températures inférieures aux moyennes des 20 dernières années. L’hiver fut également marqué par d’abondantes chutes de neige. Les sommes de températures calculées depuis le début du mois de janvier sont inférieures d’environ 170 degrés.jours par rapport à la situation moyenne, ce qui signifie un retard moyen des cultures d’une bonne semaine, voire davantage. Les images satellites montrent cependant que ce retard calculé à partir du cumul de températures serait en grande partie rattrapé fin avril. En dehors du retard phénologique calculé par une de nos deux méthodes, aucun autre élément agrométéorologique important n’est à signaler. Aucune prévision de rendement n’est faite à ce stade. [less ▲]

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See detailCombining remote sensing imagery of both fine and coarse spatial resolution to estimate crop evapotranspiration and quantifying its influence on crop growth monitoring
Sepulcre-Canto, Guadalupe; Gellens-Meulenberghs, Françoise; Arboleda, Alirio et al

in Geophysical Research Abstracts (2010)

This study has been carried out in the framework of the GLOBAM -Global Agricultural Monitoring system by integration of earth observation and modeling techniques- project whose objective is to fill the ... [more ▼]

This study has been carried out in the framework of the GLOBAM -Global Agricultural Monitoring system by integration of earth observation and modeling techniques- project whose objective is to fill the methodological gap between the state of the art of local crop monitoring and the operational requirements of the global monitoring system programs. To achieve this goal, the research aims to develop an integrated approach using remote sensing and crop growth modeling. This paper concerns the use of MSG geostationnary satellite data for the calculation of Actual Evapotranspiration and its integration into a crop growth model. [less ▲]

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See detailManaging climatic risks for enhanced food security : key information capabilities
Balaghi, Riad; Badjeck, M.-C.; Djaby, Bakary ULg et al

in Procedia Environmental Sciences (2010), 1

Food security is expected to face increasing challenges from climatic risks that are more and more exacerbated by climate change, especially in the developing world. This document lists some of the main ... [more ▼]

Food security is expected to face increasing challenges from climatic risks that are more and more exacerbated by climate change, especially in the developing world. This document lists some of the main capabilities that have been recently developed, especially in the area of operational agroclimatology, for an efficient use of natural resources and a better management of climatic risks. Many countries, including the developing world, now benefit from well-trained staff in the use of climate data, physical and biological information and knowledge to reduce negative climate impacts. A significant volume of data and knowledge about climate–agriculture relationships is now available and used by students, scientists, technicians, agronomists, decision-makers and farmers alike, particularly in the areas of climate characterization, land suitability and agroecological zoning, seasonal climate forecasts, drought early warning systems and operational crop forecasting systems. Climate variability has been extensively modelled, capturing important features of the climate through applied statistical procedures, agroclimatic indices derived from raw climatic data and from remote sensing. Predictions of climate at seasonal to interannual timescales are helping decision-makers in the agricultural sector to deal more effectively with the effects of climate variability. Land suitability and agroclimatic zoning have been used in many countries for agricultural planning, thanks to the availability of new and comprehensive methodologies; developments in climate, soil and remote sensing data collection and analysis; and improved applications in geographic information systems (GIS). Drought early warning systems are available worldwide at both national and international levels. These systems are helping decisionmakers and farmers to take appropriate decisions to adapt to short-term climatic risks. Also, operational crop forecasting systems are now becoming available at the regional and national levels. In some developed countries, several efficient and well tested tools are now available for optimizing on-farm decisions based on the combination of crop simulation models and seasonal forecasts. However, in developing countries few tools have been developed to efficiently manage crops at the farm level to cope with climate variability and climate risks. Climate change impacts on agriculture and food security have been assessed in international studies using specific and efficient methodologies and tools. Adaptation to climate change and variability can also be facilitated through effective planning and implementation of strategies at the political level. The role of technological progress, risk transfer mechanisms and financial instruments and their easy accessibility to rural people are critical elements of climate risk management. [less ▲]

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See detailExploring the potential of crop specific green area index time series to improve yield estimation at regional scale
Duveiller, Gregory; de Wit, Allard; Kouadio, Amani Louis ULg et al

in Sobrino, J. A. (Ed.) Proceedings of the 3rd International Symposium on Recent Advances in Quantitative Remote Sensing (RAQRS'III) (2010)

Crop status, such as the Green Area Index (GAI), can be retrieved from satellite observations by modelling and inverting the radiative transfer within the canopy. Providing such information along the ... [more ▼]

Crop status, such as the Green Area Index (GAI), can be retrieved from satellite observations by modelling and inverting the radiative transfer within the canopy. Providing such information along the growing season can potentially improve crop growth modelling and yield estimation. However, such approaches have proven difficult to apply on coarse resolution satellite data due to the fragmented land cover in many parts of the World. Advances in operational crop mapping will sooner or later allow the production of crop maps relatively early in the crop growth season, thereby providing an opportunity to sample pixels from medium/coarse spatial resolution data with relatively high cover fraction of a particular crop type to derive crop specific GAI time series. This research explores how to use such time series derived from MODIS to produce indicators of crop yield using two approaches over part of Belgium. The first method consists in looking at metrics of the decreasing part of the GAI curves when senescence occurs. Such metrics, like the position of the inflexion point, have been shown to be significantly correlated to yield. The second approach is to optimize the WOFOST model used in the European Crop Growth Monitoring System (CGMS) based on the GAI time series. Results show that, although the optimized model shows considerably better performance than the model running on the default parameter, the model is sometimes outperformed by the simpler metric approach. In all cases, indicators including remote sensing information provide better estimates that the average yield of previous years. [less ▲]

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