Evaluation of an electronic nose for the early detection of organic overload of anaerobic digesters

in Bioprocess and Biosystems Engineering (2012)

This study aims at the analysis of the utilization of an electronic nose (e-nose) to serve as a specific monitoring tool for anaerobic digestion process, especially for detecting organic overload. An ... [more ▼]

This study aims at the analysis of the utilization of an electronic nose (e-nose) to serve as a specific monitoring tool for anaerobic digestion process, especially for detecting organic overload. An array of non specific metal oxide semiconductor gas sensors were used to detect process faults due to organic overload events in twelve anaerobic semi-continuous reactors of 1.8 L. Three different load strategies were followed (i) a cautious organic load (1.3 gVS•L-1•day-1); (ii), an increasing load strategy (1.3 to 5.3 gVS∙L-1•day-1) and (iii) a cautious organic load with load pulses of up to 12 gVS•L-1•day-1. A first monitoring campaign was conducted with three different substrates : sucrose, maize oil, and a mix of sucrose/oil during 60 days. The second campaign was run with dry sugar beet pulp during 45 days. Hotelling's T²-value and upper control limit to a reference set of digesters fed with a cautious OLR (1.3 gVS•L-1•day-1), was used as indirect state variable of the reactors. Overload situations were identified by the e-nose apparatus with Hotelling’s T²-values at least 4-times higher in magnitude than the upper control limit of 23.7. These results confirmed that the e-nose technology appeared promising for online detection of process imbalances in the domain of anaerobic digestion. [less ▲]

Images 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 ?

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 ▲]

Gas sensor array applied to the monitoring of biogas process

in Gouma, Perena (Ed.) Proceedings of the International Symposium on Olfaction and Electronic Nose 2011 (2011, May)

There is a lack of simple online monitoring system to control the performances of biogas reactors. The electronic nose technology appears to be an adapted device to deliver fast information about process ... [more ▼]

There is a lack of simple online monitoring system to control the performances of biogas reactors. The electronic nose technology appears to be an adapted device to deliver fast information about process disturbances in anaerobic reactors as it is adequate for online monitoring. In this study, twelve anaerobic mini-reactors were supervised with a home-made e-nose to observe process reaction in relation to organic overloads events. Usually, to avoid overload situations, on farms reactors are not fed at maximum load capacity, resulting in non optimized biogas production. The objective of the experiment was to determine if the gas sensors array feature can be related to the process state and if an indirect state variable, giving early warning of process faults, can be derived from the e-nose response. The results demonstrated that focusing on gas phase of anaerobic reactors with a simple device composed of an array of non-specific gas sensors helped in the warning of disorders of the anaerobic digestion process. Mahalanobis distance from a cautious feeding group (group of observations indicating a good process) can be used as an indirect variable to evaluate the intensity of the state disorder. Euclidean distance has been also calculated but it was less informative than the Mahalanobis distance. [less ▲]

Prévoir la septoriose : un modèle belge au Luxembourg

in Phytoma : La Défense des Végétaux (2011), 642

Septoria leaf blight caused by Septoria tritici Roberge ex Desmaz. (anamorph of Mycosphaerella graminicola) is one of the most serious foliar diseases on winter wheat which farmers in Luxembourg. It need ... [more ▼]

Septoria leaf blight caused by Septoria tritici Roberge ex Desmaz. (anamorph of Mycosphaerella graminicola) is one of the most serious foliar diseases on winter wheat which farmers in Luxembourg. It need to take into account when deciding upon fungicide application during stem elongation. Management of S. tritici aims at keeping the top two leaf layers free from infection, as these leaves contribute most to grain yield. The model PROCULTURE has been developed to simulate the progress of the Septoria leaf blotch disease on winter wheat during the cropping season. The model has been validated in Luxembourg for 3-years (2000 to 2002) at distinct representative sites. Proculture forecasts have been shown to be correct in about 85% of all cases. This model has since 2004 been used in the Grand-Duchy of Luxemburg in order to find the optimum time of fungicide spray in fields. On average, no spray of fungicides or only one application is required to efficiently control Septoria leaf blotch. In the Oesling (north of G-D of Luxembourg), treatments based on the Septoria risk simulation model were recommended only once, in 2007. The climatic conditions of the Oesling tend to favour organic farming in a region where foliar disease pressure is very weak. [less ▲]

Regional-based typology of the main fungal diseases affecting winter wheat in the Grand-Duchy of Luxembourg

in Phytopathology (2011), 101

Despite its small territory size, the Grand-Duchy of Luxembourg (GDL) has several microclimates that result in a variability of disease severity between the South (Gutland) and the North (Oesling ... [more ▼]

Despite its small territory size, the Grand-Duchy of Luxembourg (GDL) has several microclimates that result in a variability of disease severity between the South (Gutland) and the North (Oesling). Septoria leaf blotch disease of wheat is an important disease in the GDL. Over 2003–2009, the severity was strong in Gutland (51% on average over the last two upper leaves at the late milk growth stage) and low in the Oesling (16% for the same leaves). For the years 2006, 2008 and 2009, the disease severity was less than 6% in the Oesling while it exceeded 40% in the Gutland. The second fungal disease that has become economically important is the wheat leaf rust. Over the same period, the Gutland and the Oesling showed consistently the highest and lowest disease severity respectively. In 2003 and 2007, the Gutland showed the highest disease severity with 66% and 57% respectively, whereas the lowest severity (<1%) was observed in the Oesling. Another important disease is wheat powdery mildew. The 2003 and 2009 cropping seasons showed the highest disease severity with 15% and 40%, respectively, in the Oesling whereas less than 1% severity was registered in the Gutland. Fusarium head blight was also present in the eastern part of the Gutland showing the highest prevalence and severity in 2007 and 2008 (8.5% and 8.3% respectively). These prevalence and severity percentages were significantly higher compared to the Oesling (% prevalence % severity, p = 0.049 and p = 0.012, respectively, Tukey’s test). [less ▲]

First report of the breakdown of the YR17 resistance gene to wheat stripe rust in the Grand Duchy of Luxembourg

in Journal of Plant Pathology [=JPP] (2011), 93(1), 243

Rouille brune du blé, un modèle pour évaluer les risques

in Phytoma-la défense des végétaux (2010), 637

L’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 ... [more ▼]

L’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. [less ▲]

Modelling plant diseases impact with the Belgium Crop Growth Monitoring System.

in Wery, Jacque; Shili-Touzi, I.; Perrin, A. (Eds.) PROCEEDING OF AGRO2010 the XIth ESA Congress (2010, September)

Time spray strategies for Septoria leaf blotch disease progress on winter wheat: The use of forecasting model

in Phytopathology (2010), 100

A mechanistic model, PROCULTURE, for assessing in real time the risk of progression of Septoria tritici (teleomorph Mycosphaerella graminicola) on winter wheat (Triticum aestivum L.) was used in Grand ... [more ▼]

A mechanistic model, PROCULTURE, for assessing in real time the risk of progression of Septoria tritici (teleomorph Mycosphaerella graminicola) on winter wheat (Triticum aestivum L.) was used in Grand-Duchy of Luxemburg over 2003 to 2009 to simulate disease progression in the canopy at four-replicated field experiments located in three villages (Diekirch district: Reuler; Grevenmacher district: Burmerange and Christnach), representative of the different agroclimatological zones of Luxembourg. This model has been developed in order to guide field observations on the different leaf layers and to find the optimum time of fungicide spray in fields. The model provides information which explains disease progression on the upper leaves. The relationship between disease control by fungicides and yield loss varies from site-to-site and from season-to-season. A weekly PROCULTURE recalibration is routinely done using actual disease levels observed on site. On average, no spray of fungicides or only one application is required to control efficiently the septoria leaf blotch disease. The PROCULTURE forecasts have been validated to be correct in about 85% of all cases. The treatment defined with the simulation model over 2003 to 2009 gave an earning grain yield (80%) more than the other treatments tested and as important as the double treatment for Everlange, Christnach and Burmerange. At Reuler, over 2003 to 2009, treatments based on the Septoria risk simulation model were recommended only in 2007. The climatic conditions of this site tend to favour organic farming in this region where the evolution of the foliar disease is very weak. [less ▲]

Fusarium head blight and associated mycotoxin occurrence on winter wheat in Luxembourg in 2007/2008

in Food Additives & Contaminants (2010), 27

Fusarium head blight (FHB) is among the major causes of reduced quality in winter wheat and its products. In addition, the causal fungi produce a variety of toxins. A relatively high FHB infection rate in ... [more ▼]

Fusarium head blight (FHB) is among the major causes of reduced quality in winter wheat and its products. In addition, the causal fungi produce a variety of toxins. A relatively high FHB infection rate in winter wheat was observed in 2007 and 2008 in Luxembourg. A fusariotoxin survey was carried out in 17 different geographical locations. Three groups of Fusarium mycotoxins (trichothecenes A and B and zearalenone) were analysed by a multi-detection HPLC–MS/MS method. Fusarium strains were also investigated by morphological and molecular methods. In addition, questionnaires relating to cultural practices were sent to the farmers managing the 17 fields investigated. FHB prevalence ranged from 0.3 to 65.8% (mean: 8.5%) in 2007 and from 0 to 24.5% (mean: 8.3%) in 2008. Results of morphological and molecular identification showed that the most common species isolated from diseased wheat spikes was F. graminearum (33.1%), followed by F. avenaceum (20.3%) and F. poae (17.8%). The chemical analysis revealed that 75% of the investigated fields were contaminated by deoxynivalenol (DON, range 0–8111 mg/kg). The preceding crop was highly and significantly correlated to the number of grains infected and had a significant impact on disease prevalence ( p¼0.025 and 0.017, respectively, Fisher’s F-test). A trend was found for maize as the preceding crop ( p¼0.084, Tukey’s test) to predict the amount of DON in the fields. This is the first report on the occurrence of DON and ZON in naturally infected wheat grains sampled from Luxembourg. [less ▲]