Diagnostic agronomique et agro-environnemental des successions culturales en Wallonie (Belgique)

Agronomical and agro-environmental diagnosis of crop sequences in Wallonia (Belgium). Crop sequence, recognized as a fundamental concept providing a balance both agronomic at parcel level and agro-environmental at the agro-ecosystem level, is analyzed on the scale of the Walloon agricultural regions (Belgium). This study aims to make a diagnosis of the qualitative performances of crop sequences, through the individual analysis of some of their explanatory components such as the effect of the previous crop on the next one, the observed return time of the re-occuring crops, the number of crops observed during the sequence and finally the duration of intercrop period. These four components are analyzed at parcel level, the results being aggregated at regional level. Study concerns both a spatial analysis based on a period of 7 years, and a temporal analysis aiming to observe a possible evolution, region by region, during two successive and equivalent periods. The drawn up appraisal reveals spatial differences in terms of practices linked to crop sequences, on the other hand, one quasi temporal stability of the analyzed parameters emerges from obtained results. Besides, these results constituting a contribution to an appraisal of the agriculture in Wallonia may serve as reference values for an evolution of regional agricultural practices global follow-up

Effects of grassed buffer strip management on potential denitrification in a belgian agricultural watershed

Riparian buffer strips are managed for the enhancement of water quality through control of non point source pollution. Denitrification in riparian buffer strips is thought to be the major process -with nitrate uptake by plant growth- that reduces nitrate input in surface water. We investigated the Denitrifier Enzyme Activity (DEA) to test how the buffer strip management modifies the denitrification process. The experimental site is composed of a crop field and a 11 m wide grassed buffer strip at the border between the crop field and a tributary to the Attert river, South-East Belgium. Soil samples from the crop field and the buffer strip have been submitted to different imposed conditions combining glucose, nitrate and water saturation to investigate how antecedent water regime, nitrate and carbon content affect denitrification. The work included DEA measurements on undisturbed soil cores freshly sampled. Experiments on undisturbed soil cores identify the buffer strip as more effective in denitrification (p < 0.001) than the cropped field. However, experiments on samples conditioned under imposed carbon and/or nitrate contents emphasised the importance of micro-topography

On the Use of Decision-Support Tools for Improved Irrigation Management: AquaCrop-Based Applications

Feeding more people with less water is putting efficient irrigation practices worldwide high on the agendas. As a reaction, over the last decades, numerous irrigation decision-support tools have been developed. For several reasons, the gap between farmer and modeler remained in most cases too large. The Food and Agriculture Organization of the United Nations (FAO) contributes to alleviate the encountered adoption limitations with AquaCrop and its stand-alone AquaCrop plug-in. This simple and robust field-crop-water balance has been successfully tested for a wide range of crops and regions, and its database is still expanding through worldwide contributions. The present chapter describes how AquaCrop can help irrigation advisory services draft efficient irrigation calendars that are easily applicable and adoptable: either by the elaboration of site-specific irrigation schedule calendars in chart format when the user has no access to the needed data or by the integration of its plug-in in a server/client ICT application offering centralized data management. As for the irrigation charts, studies prove 10-30% water savings, while maintaining yield and requiring minimum data. The server/client application offers an all-in advice tool, including real-time irrigation advice and yield forecasts. No adoption assessments have yet been carried out, but several ongoing pilot studies are promising

VEGETATION potentialities in food early warning systems in the Sahelian region.

peer reviewe

Spatial aggregation of low resolution satellite data for the monitoring of vegetation response to climatic stresses : analysis of the spatial heterogeneity of aggregated entities.

peer reviewedOur PhD research consists in analysing and modelling the vegetation response or sensitivity to climatic stresses with low satellite imagery. In that framework, the selection of optimal calibration sites is very important. These sites should be characterised by a stable and homogenous land cover over large area. Here we analyse the spatial heterogeneity of the aggregation entities (EU-NUTS 2) used by the MARSFOOD programme for the extraction of regional NDVI-means

Performance of leaf wetness sensor used in winter wheat disease management

Wetness on crop leaves has particular epidemiological significance because many fungal diseases affect plants only when free moisture is present on leaves. The leaf wetness sensor detects the presence of wetness on a leaf’s surface, enabling researchers and producers to forecast disease and protect plant canopies, and consequently to optimize fungicide application and often reduce environmental load. This research project aimed at better understanding the leaf wetness duration and its influence in winter wheat disease. Measurement of surface wetness duration by three electronic flat-plate sensors (Model 237-Campbell Scientific, Inc) in wheat fields were compared with tactile and visual observations in replicated field experiments at the site of Arlon (Belgium) during the period May-July 2006 and April-July 2007. Performances of the sensor were evaluated against SWEB model outputs and visual observations of disease symptoms. On the field, dew-onset and dry-off of wetness on leaves were observed visually (with a flash light for dew-onset) at 15-minute intervals. Each sensor was placed close the flag leaf. For the three sensors, the two dew-onset and dry-off times measured in both 2006 and 2007 crop seasons gave a leaf wetness duration (LWD) which was on average one hour less than visual observations. In order to establish a relationship between the surface wetness periods and wheat foliar diseases, LWD was compared with the Septoria leaf blotch (SLB) development risk (main winter wheat disease). A minimal surface wetness duration favourable to infection for SLB was established.Weather-radar data ; Rainfall ; Septoria tritici ; Forecasting system ; Winter wheat ; Epidemiological model ; Surface wetness duration ; Spatializatio

Rouille brune du blé, un modèle pour évaluer les risques

peer reviewedL’article présente un outil de prévision de la rouille brune au G.-D. de Luxembourg. De 2000 à 2003, cette maladie apparaissait à la fin de l’épiaison, mais depuis 2003, elle apparaît de plus en plus tôt (GS45 stade gonflement). Cette apparition précoce est probablement liée à des températures printanières supérieures par rapport à la normale 1971-2000. Une analyse des données météorologiques nocturnes et des données d’observation de la maladie sur quatre sites expérimentaux (Everlange, Christnach, Burmerange et Reuler) entre 2000 et 2003 a révélé une forte corrélation positive entre la prédiction de la maladie basée sur le critère d’au moins 12 heures consécutives avec une température comprise entre 8 et 16°C et une humidité supérieure à 60% et la maladie observée sur la F1 (R = 0.93 ; P < 0.05) et sur la F2 (R = 0.87 ; P < 0.05). Les sorties de ce modèle qui a été développé sur base d’une approche stochastique ont été utilisées dans les bulletins d’avertissements diffusés conjointement par le Centre de Recherche Public – Gabriel Lippmann et l’Université de Liège-Campus d’Arlon à partir de 2004. La mise en application de ce modèle a montré un taux de réussite oscillant entre 80 et 85% pour la simulation de la rouille brune au G.-D. de Luxembourg. L’effort se poursuit pour spatialiser les sorties du modèle sur tout le territoire luxembourgeois et faciliter son utilisation par tous les vulgarisateurs agricoles