envitam phd student day 2014 abstract book

Graduate School onEnvironmental Sciences, Technologies and Management

(ENVITAM)

Proceedings of the

ENVITAM PhD Student Day 2014

March 5, 2014Université catholique de Louvain, Louvain-la-Neuve, Belgium

Editor: Sébastien Lambot

Contents 3

Contents

Program of the Day 5

1 Water and Environment 7Soil piping: detection, hydrological functioning and modelling . . . . . . . . . . . . . . . . . . . . . . . . . 7Factors explaining on-site irrigation performance variability in Triffa’s irrigated perimeter (East Morocco) . . 8Groundwater pressure mapping in Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9In vitro screening for drought tolerant somaclones and genetic diversity in wheat (Triticum durum. Desf.) . . 10Joint Estimation of Soil Moisture Profile and Hydraulic Parameters by Ground-penetrating Radar Data As-

similation with Maximum Likelihood Ensemble Filter . . . . . . . . . . . . . . . . . . . . . . . . . . 11Experiment design for a hydrogeophysical investigation of the unsaturated zone of a karst system . . . . . . . 12Karst hydrogeology of the underground Lesse river in Furfooz (Belgium) Tracer-tests interpretation and mod-

eling : first results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Soil infrastructure evolution and its effect on water transfer processes under contrasted tillage systems with

preliminary results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Rhodococcus erythropolis, a good candidate for an in-situ bioaugmentation starter. . . . . . . . . . . . . . . 15A real-time flow Muskingum forecasting model for three main station of the Medjerda River . . . . . . . . . 16Regionalization and contribution to the study of reservoirs sedimentation: Lakes of Cape Bon and the Tunisia

Central . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Definition of an interaction index between mining activities and groundwwater resources in the Walloon Region. 18Water uptake efficiency of a maize plant - A simulation case study . . . . . . . . . . . . . . . . . . . . . . . 19Vadose zone studies at an industrial contaminated site: the vadose zone monitoring system and cross-hole

geophysics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Transmissive and capacitive behavior of the unsaturated zone in Devonian limestones of the Calestienne

(Belgium) and implications for the functioning of the epikarstic aquifer. . . . . . . . . . . . . . . . . . 21Developping an optimal soil and water quality monitoring network for the Triffa irrigated perimeter (Eastern

of Morocco) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Changes in soil properties after implementation of soil and water conservation measures . . . . . . . . . . . 23

2 Towards Sustainable Agroecosystems 25The potential of reforesting landscapes to restore native floristic biodiversity and enhance livelihoods in Ecaudor 25Carbon associated with clay and fine silt as an indicator for SOC decadal evolution under different residue

management practices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Chemical Hydrolysis of Fagus sylvatica Wood: Dilute Acid vs. Alkaline Treatment . . . . . . . . . . . . . . 27Autonomous robots: a potential weapon for farmers in their battle against weeds? . . . . . . . . . . . . . . . 28Development of formulated elicitors to control bioagressors of wheat: how? . . . . . . . . . . . . . . . . . . 29Development of a hybrid LCA model for the wood construction sector in Walloon region . . . . . . . . . . . 30Characterization of fatty acid and carotenoid production in an Acutodesmus microalga isolated from the

Algerian Sahara . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Some Interesting Sources of Plant Seed Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3 Innovation in Environmental Engineering 33Full-wave modeling of near-field ground-penetrating radar data for imaging root water uptake dynamics . . . 33Non-destructive sensing of tree trunk internal structures and wood properties using microwave radar imaging

and full-wave inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Wildflower strips, an alternative to pesticide? A tool for conservation biological control: impact of functional

diversity and mowing regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Information content in frequency-dependent, multi-offset GPR data for layered media reconstruction using

full-wave inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

List of participants 37

Program of the Day

VenueThe ENVITAM PhD Day 2014 will be held in Louvain-la-Neuve, Place Croix du Sud 4, buildingCarnoy B0 (Floor 0) in Rooms B059 Théodore Schwann (Posters, coffee breaks and lunch) andB091 Jean-Baptiste Carnoy (Oral presentations).

Schedule

• 8h30-9h00: Arrival of the participants.

• 9h00-9h20: Introduction by Sébastien Lambot and Marnik Vanclooster.

• 9h20-9h40: "Factors explaining on-site irrigation performance variability in Triffa’s irri-gated perimeter (East Morocco)" by Nicolas Feltz.

• 9h40-10h00: "Joint Estimation of Soil Moisture Profile and Hydraulic Parameters byGround-penetrating Radar Data Assimilation with Maximum Likelihood Ensemble Filter"by Anh Phuong Tran.

• 10h00-10h20: "Experiment design for a hydrogeophysical investigation of the unsaturatedzone of a karst system" by Arnaud Watlet.

• 10h20-11h20: Coffe break and Poster Session I.

• 11h20-11h40: "Rhodococcus erythropolis, a good candidate for an in-situ bioaugmentationstarter." by Thibaut Masy.

• 11h40-12h00: "Definition of an interaction index between mining activities and ground-wwater resources in the Walloon Region." by Louise Collier.

• 12h00-12h20: "Vadose zone studies at an industrial contaminated site: the vadose zonemonitoring system and cross-hole geophysics" by Natalia Fernandez de Vera.

• 12h20-13h40: Lunch.

• 13h40-14h00: "Carbon associated with clay and fine silt as an indicator for SOC decadalevolution under different residue management practices." by Sylvain Trigalet.

• 14h00-14h20: "Autonomous robots: a potential weapon for farmers in their battle againstweeds?" by Sruthi Moorthy Krishna Moorthy Parvathi.

• 14h20-14h40: "Development of a hybrid LCA model for the wood construction sector inWalloon region" by Vanessa Zeller.

• 14h40-15h00: "Full-wave modeling of near-field ground-penetrating radar data for imag-ing root water uptake dynamics" by Nicolas Mourmeaux.

5

6 Contents

• 15h00-16h00: Coffe break and Poster Session II.

• 16h00-16h20: "Non-destructive sensing of tree trunk internal structures and wood proper-ties using microwave radar imaging and full-wave inversion" by Laurence Mertens.

• 16h20-16h40: "Wildflower strips, an alternative to pesticide? A tool for conservation bio-logical control: impact of functional diversity and mowing regime" by Séverin Hatt.

• 16h40-17h00: "Information content in frequency-dependent, multi-offset GPR data for lay-ered media reconstruction using full-wave inversion" by Albéric De Coster.

• 17h00-17h30: Best poster and best presentation Awards

• 17h30-18h00: Closure and reception

List of posters

• "Soil piping: detection, hydrological functioning and modelling" by Jean-Baptiste Got.

• "Groundwater pressure mapping in Africa" by Ouedraogo Issoufou.

• "In vitro screening for drought tolerant somaclones and genetic diversity in wheat (Triticumdurum. Desf.)" by Nadia Sandra Kacem.

• "Karst hydrogeology of the underground Lesse river in Furfooz (Belgium) Tracer-tests in-terpretation and modeling : first results" by Lorraine Dewaide.

• "Soil infrastructure evolution and its effect on water transfer processes under contrastedtillage systems with preliminary results" by Nargish Parvin.

• "A real-time flow Muskingum forecasting model for three main station of the MedjerdaRiver" by Sahar Abidi.

• "Regionalization and contribution to the study of reservoirs sedimentation: Lakes of CapeBon and the Tunisia Central" by Olfa Hajji.

• "Water uptake efficiency of a maize plant - A simulation case study" by Félicien Meunier.

• "Transmissive and capacitive behavior of the unsaturated zone in Devonian limestones ofthe Calestienne (Belgium) and implications for the functioning of the epikarstic aquifer." byAmaël Poulain.

• "Developping an optimal soil and water quality monitoring network for the Triffa irrigatedperimeter (Eastern of Morocco)" by Karim Andich.

• "Changes in soil properties after implementation of soil and water conservation measures"by Pablo Borja.

• "Chemical Hydrolysis of Fagus sylvatica Wood: Dilute Acid vs. Alkaline Treatment" byKrystian Miazek.

• "Development of formulated elicitors to control bioagressors of wheat: how?" by GeraldineLe Mire.

• "Characterization of fatty acid and carotenoid production in an Acutodesmus microalgaisolated from the Algerian Sahara" by Borhane Samir Grama.

• "Some Interesting Sources of Plant Seed Oil" by Aman Paul.

Section 1

Water and Environment

Soil piping: detection, hydrological functioning and modelling

J.-B. Got, C. Bielders, and S. Lambot

Earth and Life Institute, Environmental Sciences, Université caholique de Louvain, Croix du sud 2, bteL7.05.02, 1348 Louvain-La-Neuve, Belgium

Email: [email protected]

Abstract (Poster)Soil piping remains a relatively unexplored phenomenon despite its substantial impacts onwatershed-scale water and sediments transfer in numerous locations around the world. In verygeneral terms, soil piping refers to the formation of sub-surface pipes or tunnels due to the erosiveaction of water flowing through the soil. Presumably initiated by biopores or desiccation cracks,these natural pipes are often considered as the largest category of macropores (sufficiently largefor water to sculpt their form) and have the potential to provide subterranean networks with thegreatest hydrological connectivity (Jones et al., 2010). Present in a wide range of pedoclimaticenvironments across the globe (Verachtert et al., 2011), these networks act as conduits for water,sediments, gases and solutes (Smart et al., 2012). Over the past forty years, research has demon-strated the important contribution of natural soil pipes in water transfer and especially their role inaccelerating subsurface flows and expanding stormflow contributing area. However, these studiesdo not yet allow to fully assess their hydrological functioning. According to Jones et al. (2010),this deficiency is due to a lack of continuous measurements and the complex characterization ofpipe networks (their underground and heterogeneous nature makes the number of pipes, their di-mensions, positions and connectivity very difficult to estimate). Following these observations, wepropose, in this research project, to develop an integrated methodology that will allow a better un-derstanding of natural soil pipes hydrological behavior at the hillslope scale in the specific contextof Loess-derived soils (Gueule valley, Sippenaeken, Belgium). This novel methodology involves:1. Non-invasive, high-resolution imaging using ground-penetrating radar (GPR) using the latestadvances in signal processing and object detection in order to characterize the pipe network (num-ber of pipes, dimensions, positions and connectivity) as well as the position of any imperviouslayer. 2. The installation of flow meter and piezometer networks to fully characterize the linkbetween pipeflow and the water table (which is crucial but neglected in almost every researchuntil today). These monitoring networks should present high temporal and spatial resolutions.Combining this information at the hillslope scale should not only allow to better understand thehydrological behavior of a pipe network in Loess-derived soil but also to model its hydrologicalfunctioning.

7

8 Proceedings ENVITAM PhD Day 2014

Factors explaining on-site irrigation performance variability in Triffa’sirrigated perimeter (East Morocco)

Nicolas Feltz and Marnik Vanclooster



Abstract (Oral)Irrigated agriculture remains the largest consumer of global freshwater resources, and improvingwater management in irrigated agriculture is a key issue to solve the global water and food crisis.The design, planning and improvement of irrigation often rely on the assessment of irrigation per-formance (IP), using efficiency indicators. However, the use of the efficiency concepts can leadto misinterpretation and is frequently criticized. Moreover, they only include technical, on-siteand time-specific considerations, while socio-economical issues, management and scale effectsare neglected. Actual performances are then likely to be more variable than considered, and thisvariability must be quantified. In this research, we aim to assess and model technical irrigation per-formance for the Triffa’s irrigation perimeter in East Morocco. The objectives are to characterizethe irrigation long term technical performance and to analyze the variability of this performancein terms of technical, agronomic and socio-economical parameters with a particular attention de-voted to the associated uncertainty in order to improve the scaling relationships of performance.For meeting the study objectives, background data (land use and land use pattern, soil data, topog-raphy,..) were collected. A field survey and farm field questionnaire allowed characterizing theirrigation practices in the subregion and collecting additional field data for performance evalua-tion. The data collection step was followed by a modeling step, allowing assessing i) the technicalirrigation performance, ii) the uncertainty associated with the irrigation performance evaluationand iii) the factors and processes explaining the variability of assessed performance. The resultsshow that IP, when including irrigation management practices, is much more variable than usu-ally considered. Observed performance variability is related to total amount of irrigation waterapplied over the year, which can itself be linked to many factors. Some of these are agronomicor technical, such as application technology or cropping pattern, but other are socio-economicaland even nearly psychological. This study indeed shows that, in the study area, IP variabilityis linked to farm size when drip irrigation is practiced and to both crop and "citrus area to farmarea" ratio when traditional surface irrigation is. Those sometimes surprising relationship can beexplained by case specific issues, highlighting the need to include such socio-economic consider-ations into the irrigation evaluation process. The developed method, based on the water balance,can be performed with widely available data.

1. Water and Environment 9

Groundwater pressure mapping in Africa

Ouedraogo Issoufou, Defourny Pierre and Marnik Vanclooster

Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 2, Box 2, B-1348 Louvain-la-Neuve, Belgium.


Abstract (Poster)Africa is the second driest continent of the world after Australia. The continent comprises only9% of the global fresh water resources, but supports 15% of the world population (Mazvimaviet al.; 2013). The booming population in Africa increases considerably the freshwater demandof the domestic, agricultural, and industrial sectors. Parts of these demands are fulfilled by in-creasing groundwater extractions. Yet, the increasing exploitation of groundwater has also re-sulted in significant pressures. As well natural factors, as anthropogenic pressures threaten thesustainability of groundwater exploitation at the continental scale. But the pressures exerted bythe agricultural sector is of primary concern as agriculture is the most important consumer offresh water at the continental and global scale. The general objective of the research is the map-ping of groundwater vulnerability and pressures at the scale of the in African continent usingmodern digital mapping, advanced data fusion and pressure modelling techniques. To achievethis objective, the proposed approach consists of using the most recent continental scale informa-tion on land use, climate, agricultural pressure, soil and groundwater. The methodology will bebased firstly on a detailed study of the literature. Secondly a compilation of existing availabledatabases will be made. Thirdly the modelling methodology will be designed and implementedin a Global Information System (GIS). Finally, smaller scale case studies will be selected allow-ing to validate the methodology. The results of this study will provide theoretical and practicalbases for better management and protection of groundwater resources at the scale of the Africancontinent. Key words: Africa, groundwater, modeling, sustainability, mapping, data fusion, GIS.Mazvimavi D., Maathuis B., Kirugara D., Fernandez D. (2013). Water resources management(http://www.bragma.eu/home/files/GMESAfrica_WaterResourcesManagementChapter_Final.pdf).


In vitro screening for drought tolerant somaclones and genetic diver-sity in wheat (Triticum durum. Desf.)

Kecem N.S. (1, 2) , Delporte F. (1), Djekoun A. (2), Watillon B. (1)

(1) Centre Wallon de Recherches Agronomiques. CRA-W Département Sciences du Vivant, Bâtiment Jean-Baptiste de la Quintinie, Chaussée de Charleroi, 234 B-5030,(2) Université Constantine 1, Faculté des Sciences de la Nature et de la Vie, Département de Biologie etEcologie Végétale B.P. 325 Route Ain El Bey, Constantine 25017, Algérie


Abstract (Poster)Environmental stresses result in water deficiency for the plants, thus impairing its numerous bio-logical roles. In vitro screening for stress tolerance will have its significance in identifying cultivarswith optimal stress tolerance and productivity. In the present study, drought-induced alterationsin callogenesis rate and duration timing, regeneration rate, fresh and dry callus weight, and callusarea were assessed in stressed versus non-stressed mature embryo cultures of three durum wheatgenotypes. Water stress was imposed by increasing concentrations of polyethylene glycol in theinduction medium (PEG 6000) from 0 to 1.5 mPA during a 30 day-period of culture. With theaim of selecting drought tolerant lines in durum wheat, an additional mutagen based approachusing EMS was followed. The three durum wheat varieties characterized by different water stresstolerances in the field, showed distinct behaviors under osmotic stress in vitro. Callus derivedfrom the the most drought tolerant variety Djeneh Khetaifa (DK) exhibited more tolerance in vitrocompared with Oued Zenati (OZ) and Waha (W) varieties. Compared to controls, PEG signifi-cantly affected callus growth resulting in a gradual decrease in all measured growth parameters.Besides, the effect of the osmotic stress on the oxalate oxidase (OXO) enzyme activity and em-bryogenesis ability was evaluated after 8, 15 and 30 days of culture. An intense OXO staining wasobserved after 8 days of culture in all varieties, but was less important in the resistant ones. Thestaining appeared to gradually decrease over culture time. The increase in PEG concentration wasaccompanied by an augmentation of OXO enzyme activity. As far as mutagen based approach isconcerned the lethal EMS dose was determined on 30-day old callus derived from EMS treatedmature embryos. The first obtained results indicate that EMS causes a decrease in callus growth inboth the presence and the absence of PEG, as well as in the regeneration rate, and a few seedlingsdisplayed anomalies. EMS treatment does not seem to have induced increased PEG tolerance intreated calli. A study with a larger number of embryos would be needed to confirm the results.Keys words: Triticum durum, Mature embryo, Drought stress, Callogenesis, Poly Ethylene Glycol(PEG), Ethyl Methyl Sulfonate (EMS).


Joint Estimation of Soil Moisture Profile and Hydraulic Parameters byGround-penetrating Radar Data Assimilation with Maximum Likeli-hood Ensemble Filter

Anh Phuong Tran (1), Marnik Vanclooster (1), Milija Zupanski (2), and Sébastien Lambot (1)

(1) Environmental Sciences, Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve,Belgium.(2) Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, USA.


Abstract (Oral)Ground-penetrating radar (GPR) has recently become a powerful geophysical technique to char-acterize soil moisture at the field scale. Compared to the airborne/spaceborne remote sensingtechniques, GPR can provide soil moisture data with a much higher spatial resolution (around 0.1-1 m). Its characterization depth is also larger for the fact that GPR works near the soil surface. Wedeveloped a data assimilation scheme to simultaneously estimate the vertical soil moisture profileand hydraulic parameters from time-lapse GPR measurements. The assimilation scheme includesa soil hydrodynamic model to simulate the soil moisture dynamics, a full-wave electromagneticwave propagation model and petrophysical relationship to link the state variable with the GPRdata, and a maximum likelihood ensemble assimilation algorithm. The hydraulic parameters areestimated jointly with the soil moisture using a state augmentation technique. The approach allowsfor the direct assimilation of GPR data, thus maximizing the use of the information. The proposedapproach was validated by numerical experiments assuming wrong initial conditions and hydraulicparameters. We compared three scenarios: open-loop (without assimilation), surface soil moistureassimilation and GPR assimilation. The synthetic soil moisture profiles were generated by theHydrus-1D model, which then were used by the electromagnetic model and petrophysical rela-tionship to create "observed" GPR data. The results show that the data assimilation significantlyimproves the accuracy of the hydrodynamic model prediction. Compared with the surface soilmoisture assimilation, the GPR data assimilation better corrects the soil moisture profile and hy-draulic parameters. The results also show that the estimated soil moisture profile in the coarse soilconverges to the "true" state more rapidly than in the fine one. Of the three unknown parametersof the Mualem-van Genuchten model, the estimation of n is more accurate than that of α and Ks.The approach shows great promise to use GPR measurements for the soil moisture profile andhydraulic parameter estimation at the field scale.


Experiment design for a hydrogeophysical investigation of the unsatu-rated zone of a karst system

Arnaud Watlet (1), Michel Van Camp (2), Olivier Kaufmann (1)

(1) University of Mons, Department of Geology and Applied Geology, Mons, Belgium(2) Royal Observatory of Belgium, Seismology-Gravimetry Section, Brussels, Belgium


Abstract (Oral)Karst systems provide 25% of drinkable water in the world. Present knowledge of karsts hasevidenced the importance of the unsaturated zone on the water dynamics. The Karst AquiferReseArch by Geophysics (KARAG) project aims at leveraging our previous experience in karst,hydrogeology, gravimetry and geophysics to understand the water dynamics and storage in theunsaturated zones, and more specifically the epikarst zones, of a karst system, which are often thelesser known part in the karst water balance and dynamics. For a better understanding of the infil-tration processes within the epikarst, insights of spatial and temporal changes in the groundwatercontent are needed. However, high underground heterogeneities of such geologically complexenvironments are major constraints for such a purpose. Geophysical tools used in hydrology arenon-destructive ways to investigate groundwater content characteristics. On one hand, an electri-cal resistivity tomography (ERT) monitoring system is used to image, at least on a daily basis, thespatial variability of resistivities due to the complex geometry of the epikarst. On the other hand,gravimetric measurements can provide valuable insights on changes in the groundwater contentby measuring variations in the underground densities. Coupling surface and in cave measurementslead to crucial information on the water masses stored in the unsaturated zone. Additional mon-itoring tools are required: (1) Flow recorders inside the cave to monitor discharge, temperatureand conductivity of the water that percolate throughout the unsaturated zone. For this purpose,we benefit from the Rochefort Cave Laboratory (Belgium) infrastructures that provide time seriesof data (up to 15 years). (2) A network of time domain reflectometry (TDR) probes to monitorground moisture. (3) Piezometers and other hydrogeological tools to monitor charge of the satu-rated zone. We present the set up of a permanent ERT monitoring system and the first gravimetricobservations at the Rochefort Cave Laboratory site. We will show our design for such experiments,how we intend to put the pieces of the karst puzzle together using indirect measurements (ERT,gravimetry) and direct measurements (dripping rate, moisture content, etc.) and how intricate itcan be to work with such geologically heterogeneous systems.


Karst hydrogeology of the underground Lesse river in Furfooz (Bel-gium) Tracer-tests interpretation and modeling : first results

Dewaide Lorraine

University of Namur, Geology Department, Belgium


Abstract (Poster)In Furfooz, near Dinant (Belgium), the Lesse river is partially infiltrating through a sinkhole (Troudes Nutons) and is re-emerging 800 m downstream at a resurgence called the Trou de La Loutre.According to the hydrological conditions, the discharge of the subterraneous stream varies be-tween 5 and 65 l/s which is rather low. The specificity of this underground system is the existenceof an important volume of standing water (the Puits des Vaux lake) on the flow path. The in-fluence of this reservoir on the hydrogeological behavior of the underground Lesse was neverstudied. In order to understand and to characterize the hydrogeology of the active system, threetracer-tests were performed in mid water (19 l/s) and low water (10,5 l/s and 7 l/s) flow condi-tions. Conservative tracer (fluoresceine or rhodamine) was injected in the sinkhole and automaticsampling devices were installed in several location where the access to the subterraneous river ismade possible by the development of annexed karstic networks. The breakthrough curves (BTC)obtained via the different tests show similarities in particular in the existence of a double peakdownstream the Puits des Vaux lake. Interpretation of the BTC’s along with field observationsand monitoring of various parameters (temperature, conductivity and water level) along the flowpath, suggest that the dual peak is due to the presence of the lake on the tracer route. Indeedthis lake is acting as a pool relatively quiescent at the surface and in which the flow coming fromupstream is running. Two flows are then coexisting: one spreading slowly in subsurface waterscausing temporary detention of the tracer; the other consisting in a more convective and quickerflow which runs downstream at greater depth. The dual flow results in the creation of a dual peakedBTC. Evaluation of the solute-transport parameters was performed by application of a transportmodel called OTIS (One-dimensional Transport with inflow and Strorage) based on the classicaladvection-dispersion equation but including mass transfer processes between mobile and immo-bile zones developed along the whole traced system (two-region non-equilibrium model). Resultsof the three tracer-tests modeling show consistent parameters evaluation in particular in the cali-bration of the mobile and immobile flow sections. Although the geometry of the active system israther constant along the underground stream in various flow conditions, the Puits des Vaux lakeshows important changes in its geometry between the different test. Its geometry seems to have amajor influence on the appearance of the dual peaked BTC’s downstream.


Soil infrastructure evolution and its effect on water transfer processesunder contrasted tillage systems with preliminary results

Parvin N., Chélin M., Hiel MP., Barbieux S., Degrune F., Vandenbol M.,Garré S., Bodson B., Colinet G., and Aurore Degré

Gembloux Agro-Bio Tech


Abstract (Poster)The heterogeneity of soil structure and porosity are highly influenced by external factors liketillage systems and other land management approaches. The aim of this project is to investigate theeffect of soil tillage along with residue management on the changing pattern of soil structure. Thisinvestigation will help to emphasize the different water flow dynamics especially the preferentialflow processes through the soil that are influenced by the changes in structural distribution in thesoil profile. Mostly the preferential flow of water is addressed by the apparent velocity throughthe soil but this study will focus on soil structure along with soil moisture dynamics at pedon scaleor more specifically at aggregate scale. The experimentation has been started from June 2013in the research field known as Solcouvert (objects: strip-till (ST) versus winter ploughing (WP))and Solresidus (objects: no-till with organic matter restitution (NI) versus no-till without organicmatter restitution (NO)). Soil profile description has been carried out in the four objects of landmanagement. Soil sampling has been done in different depths of soil according to the soil profiledescription. Soil samples will be used for the measurement of water retention capacity (done),hydraulic conductivity and x-ray microtomography. The assessment of soil water retention curveswith pressure plate technique show significantly (p<0.05) higher water retention (Hwr) in WPthan ST at 9.8 to 98 hPa, Hwr in WP than NI at 39 to 14710 hPa, Hwr in ST than NI at 294 to14710 hPa and Hwr in WP than NO at 69 to 98 hPa. There was no significant difference in thewater retention between NO and NI and ST and NO. Since, tillage practices generally increasesoil porosity, the correlation between soil hydraulics and porosity distribution would expect to bedifferent for different tillage systems. In our study, WP retains more water due to the increaseof macroporosity than ST, NI and NO. As the changes in soil structure are usually noticed in therange of 9.8 to 98 hPa, so, we can conclude that there is certainly structural change between WPand conservation practices of ST, NI and NO. In our study, there will be also soil moisture sensors(Decagon 10HS, 5TM and ML3 Thetaprobe) to capture the total soil moisture networks in the fieldunder four different trials. The soils from the different trials and also from different depths (0-15,25-30 and 50-60 cm) were used for zone specific calibration of the sensors. All the experimentswill be repeated twice a year. For the specific spatio-temporal comparison, the monitoring resultsfrom electrical resistance tomography will be available from the collaborated project of the samefaculty.


Rhodococcus erythropolis, a good candidate for an in-situ bioaugmen-tation starter.

Thibaut Masy(1), David Caterina(2), Olivier Tromme(3), Serge Hiligsmann(1), Frédéric Nguyen(2),Philippe Thonart(1)

(1) Walloon Center of Industrial Biology, Departement of Chemistry and Bio-Industries, Gembloux Agro-BioTech, University of Liège, Gembloux, Belgium(2) Applied Geophysics, Department ArGEnCo, University of Liège, Liège, Belgium(3) Sanifox SPRL, Chevetogne, Belgium


Abstract (Oral)In-situ bioremediation is as a green and cheap process to clean soils from pollution compared toother techniques which often imply the excavation of soils. Amongst the bacteria used, Rhodococ-cus erythropolis appears as one of the best candidates for bioaugmentation. In fact, this speciesforms biofilms and produces biosurfactants to solubilize hydrocarbons, which are consequentlymore available for this bacterium and the endogenous oil-degrading flora. Moreover, its largegenome allows the degradation of various persistent pollutants, such as polyaromatic hydrocarbonsor sulfur-containing hydrocarbons. In addition to these benefits, our strain Rhodococcus erythro-polis T902.1, isolated from a dried polluted soil, resists to desiccation during industrial processor drought, and maintains its biodegradation capabilities. To test this strain in field conditions,a bioaugmentation experiment at a pilot scale was initiated in partnership with the DepartmentArGEnCo, Applied Geophysics of the University of Liège. The pilot contains 2 m3 of sand, inwhich a vertical lens of highly polluted clayey soil (7200 mg of hydrocarbons/g of dry weight) wasinserted. During the first three months, 75% of the hydrocarbons content was degraded, whereasa previous biostimulation experiment with KNO3 and H2O2 did not lead to any depletion of thepollutant. This degradation was correlated with the increase of total and specific microorganisms(by a factor 13 and 10 respectively) and the almost complete NO3- consumption (from 50 to nearly0 mg/L). Furthermore, electrical resistivity tomography images of the contaminated lens also de-picted a switch in the bulk conductivity values that does not correspond to the trend followed bythe aqueous conductivity. It could be explained by the implementation of the injected bacteria andtheir production of hydrophobic biosurfactants desorbing hydrocarbons from soil particles. Thisassumption is strengthened by the fact that low concentrations of hydrocarbons were detected inpiezometers downstream of the contaminated area. Further experiments will be carried out at asmaller scale to validate this hypothesis. On the one hand, we are currently designing a protocol tofollow the biofilm formation by Rhodococcus erythropolis T902.1 with spectral induced polariza-tion (SIP) signature in sand columns of 1.5 L. On the other hand, the analysis of biosurfactants willbe performed in liquid cultures containing diesel oil, to characterize the hydrophobicity developedby the strain in presence of a common but complex pollutant. To conclude, all these character-istics showed by Rhodococcus erythropolis T902.1 make it an ideal candidate for the productionof a bioremediation starter to quickly treat hydrocarbons-polluted soils. . Furthermore, the bettercomprehension of geophysical signatures associated with such a process may lead in the future touse them as a low-cost monitoring tool for a better visualization of active remediation zones.


A real-time flow Muskingum forecasting model for three main stationof the Medjerda River

ABIDI Sahar (1), and Marnik Vanclooster (2)

(1) National Agronomic Institute of Tunis,(2) Earth and Life Institute, Environmental Sciences, Université catholique de Louvain.


Abstract (Poster (presented by Prof. Marnik Vanclooster))River flow forecasting has always been one of the most important issues in hydrology. Mod-els of flood prediction are varied; there are a big number of algorithms from simple statisticalreceipt to the partial differential equations of Saint-Venant. In Tunisia, the flood problem arisethe only perennial river, Medjerda, in particularly the plain of Ghardimaou-Jendouba-Bou Salem.The Muskingum model is the simple flood propagation model and is numerically equivalent to theSaint-Venant equations via the diffusion equation of a wave. In this research, Muskingum model isused to forecast 21 flood’s hydrographs for three stations in Medjerda River. This model requirestwo data from the upstream station one on the present time and the second on the forecasting timeand a data from the downstream station on the present time. The delays of forecasting were 2,4, 6 and 8 hours. The forecasting operation consisted in choosing reconstitution coefficients byMuskingum model for a previous flood that belong to the same season and had a near humidityindex. To evaluate the quality of 252 forecasting operations, four numeric and three graphic per-formance measures were selected. The standard deviation error ’S’ was chosen to assess the meanquality error. A big difference for the peak flow prediction offer more damage than the little flowin the beginning and the end of flood, for that the peak relative error ’S1’ was calculated. Thedifference time between observed and forecasted peak have to be the minimum, so the peak timedifference ’S2’ was defined. Hydrograph flow, Error flow and correlation between observed andcalculated flow were the graphic criteria selected in this application. In the section Ghardimaou-Jendouba, the standard deviation error ’S’ varied from 2 to 190 m3/s, the peak relative error ’S1’had low value -35 and 23% and the peak time difference ’S2’ 2 and 9 hours. While, for the sectionJendouba-Bou Salem the value of the three criteria varied respectively from 2 to 236 m3/s, -24to 30 % and -2 to 11hours. For the last section Ghardimaou-Bou Salem, the three criteria rangesbetween; 2 and 225 m3/s (for ’S’), -18 and 12% (for ’S1’) and 2 and 10 hours (for ’S2’). Theseresults are satisfactory for the three sections and all delay. That were confirmed by the mean flowerror ’E’ which where for the three section -2 m3/s for the forecasting delay 2 hours, -3 to -4 m3/sfor 4 hours, -6 to -8 m3/s for 6 hours and -8 to -13 m3/s for 8 hours. The propagation modelMuskingum gave adequate results for the flow forecasting.


Regionalization and contribution to the study of reservoirs sedimenta-tion: Lakes of Cape Bon and the Tunisia Central

HAJJI Olfa (1), and Marnik Vanclooster (2)

(1) National Agronomic Institute of Tunis,(2) Earth and Life Institute, Environmental Sciences, Université catholique de Louvain.


Abstract (Poster (presented by Prof. Marnik Vanclooster))In addition to their role as protection of the environment, the hilly lakes appear as local reserves ofwater available for agriculture. Nevertheless these hydraulic infrastructures are rather sensitive tosedimentation due to solid contributions. In Tunisia, water erosion affects nearly 3 million hectaresof agricultural land, and constitutes a threat to the sustainability of these hilly reserves. 26 hillylakes are distributed in the Tunisia central and the Ridge until the Cap Bon. To conserve thesereserves, we had research to find a simple and practical methodology which allows assessing therelative contribution of water erosion in sediment fluxes at the outlet of the small watersheds andto seek preferential links between the various explanatory attributes of sedimentation. To achievethis aims, extract a typology of the sedimentation variability of 26 hilly Lakes, is required. Themain objective of this paper is to form different classes of hilly Lakes, by using statistical method,and to define a representative lake of each class. Based on the correlation table, the correlationsbetween different variables are interpreted. Then three methods of analysis are used: the ACP; adescriptive analysis method to synthesize the most relevant information of the data, the hierarchi-cal Classification to quantify the effect of the data in prioritizing different watersheds and the linearregression type ’Step wise’ or ’Step by step’ to finally get a relationship that expresses the param-eters affecting the erosive process. By crossing the different results we try to identify a typologyof hilly Lakes and to explain the reasons for such assemblies. The results deduct three classes.The first group is the less vulnerable to the silting risk and is located on the southern and easternborders West of the ridge and on the coastal plains. The lakes of this group are characterized by alow rate of silting, a large drainage area, a low relief, hydrographic network relatively hierarchicaland an effect of precipitation and little intense runoff. A second group includes the most degradedenvironments cover almost the entire of the semi-arid zone of Central Tunisia. This group havevery abrasive potential watershed, explained by high flow coefficients related mainly to highererosive rainfall intensities associated with a moderate or accentuate topography, structure of soilover marl and a drainage non occupied and unimproved surface. A third group extends share andother sides north and south of the Ridge, has the catchment characterized by a moderate to highsedimentation rate. The sedimentation rate is governed by a more or less marl soil structure andan intense hydrodynamic compounded by the steep slopes of these basins. This study permitted toextract the preferential links between the various explanatory attributes of siltation, and to developa typology of the reservoir siltation variability.


Definition of an interaction index between mining activities and ground-wwater resources in the Walloon Region.

Louise Collier, Vincent Hallet

UNamur, Geology Department, Namur, Belgium


Abstract (Oral)Definition of an interaction index between mining activities and groundwater resources in theWalloon Region. L. Collier and V. Hallet Department of geology University of Namur - BelgiumGroundwater and rocks are the two important underground resources in Wallonia. For example,in 2010, 380 million m3 of groundwater were exploited; this volume was used to supply 80 % ofthe drinking water of the Walloon population. Rocks, whose average annual production reachesmore than 60 million tons, are extracted from 160 quarries sites. The main extracted materials are:limestone, sandstone, sand, flint, porphyry and clay. Given the high density of population and en-vironmental pressures, the spatial extension of quarries is increasingly limited. Depending of thegeological structure of the deposit, only deepening is often possible. In this context, the extractiveactivity requires groundwater dewatering whose impacts aquifer hydrogeological regime. This isdue to the fact that 75 % of the extracted rocks are classified as aquifer materials. The objectives ofthis study are to estimate the interaction between extractive activities where dewatering operationsoccur and groundwater resources and to calculate an interaction index based on geological and hy-drogeological settings. First, mathematical models are used (Visual Modflow software) to modelthe behavior of groundwater in different hydrogeological contexts. Conceptual models, consist-ing of theoretical representations of all types of situations likely to be encountered in quarriesin Wallonia, are tested. Geological and hydrogeological parameters (as hydraulic conductivities,dewatering depth, boundary conditions, etc.) introduced in the model are modified. Results areused to determine the importance of each parameter in terms of pumped volumes and drawdownextension zones. Various case studies in Wallonia are also characterized and modeled. Based onthe results, an interaction index is calculated to rank quarries according to their deepening andtheir interference on groundwater resources. Its calculation is based on the methods used for theestimation of natural hazards and the assessment of the vulnerability of aquifers. The objective ofthis ranking is to determine, using the quarry extension and simple hydrogeological parameters,the extent of hydrogeological investigations that have to be conducted during a feasibility study.These could be limited to a simple hydrogeological description up to a detailed flow and transportmodel in non-steady conditions.


Water uptake efficiency of a maize plant - A simulation case study

Félicien Meunier (1), Daniel Leitner (2) , Gernot Bodner (3),Mathieu Javaux (4,5), Andrea Schnepf (5)

(1) Faculty of Biological Agricultural and Environmental Engineering, Université catholique de Louvain,Belgique(2) Computational Science Center, Vienna(3) Division of Agronomy, BOKU University of Natural Resources and Life Sciences, Vienna(4) Environmental Sciences, Université catholique de Louvain(5) Forschungszentrum Jülich GmbH, Agrosphere (IBG-3), D-52425 Jülich, Germany


Abstract (Poster)Water uptake by plant roots is a complex mechanism controlled by biological and physical prop-erties of the soil-plant-atmosphere system and affects a major component of the water cycle, tran-spiration. This uptake of water by plants is one of the major factors of plant development. Sincewater uptake occurs at the roots, root architecture and hydraulic properties both play a crucial rolein plant productivity. A fundamental understanding of the main processes of water uptake willenable better breeding of drought resistant plants and the improvement of irrigation strategies. Inthis work we analyzed the differences of root water uptake between idealized genotypes of a plantusing mathematical modelling. The numerical simulations were performed by the R-SWMS soft-ware (Javaux et al., 2008). The model describes 3-D water movement in soil by solving Richard’sequation with a sink term representing root uptake. Water flow within the root xylem networkand between soil and root is modelled based on water pressure gradients and calculated accordingto Doussan’s model. The sink term is calculated by integration of local uptakes within rootedrepresentative elementary volumes of soil. The plant water demand is described by a boundarycondition at the base of the shoot. We compare the water uptake efficiency of three types of rootsystem architectures of a maize plant. Two are actual architectures from genotypes showing signif-icant differences regarding the internodal distance, the root growth rate and the insertion angle oftheir primary roots. The third one is an ideotype according to Lynch of the maize plant designed toperform better in one dry environment. We generated with RootBox five repetitions of these threeroot systems with the same total root volume and simulated two drought scenarios at the floweringstage (lack of water at the top or at the bottom of the soil domain). We did these simulations fortwo distinct distributions of local conductivities of root segments based on literature values. Thisnumerical experiment shows significantly different behaviors of the root systems in terms of dy-namics of the water uptake, duration of the water stress or cumulative transpiration. The rankingof the maize architectures varied according to the considered drought scenario. The performanceof a root system depends on the environment and on its hydraulic architecture suggesting that wealways need to take the genotype-environment interaction into account for recommending breed-ing options. This study also shows that an ideotype must be built for a specific environment: theone we created experienced difficulties to transpire when placed in different conditions it has beendesigned for. By mathematical simulation we increased the understanding of the most importantunderlying processes governing water uptake in a root system.


Vadose zone studies at an industrial contaminated site: the vadosezone monitoring system and cross-hole geophysics

Natalia Fernández de Vera (1) Jean Beaujean (1) Pierre Jamin (1) Frédéric Nguyen (1) Ofer Dahan(2) Marnik Vanclooster (3) Serge Brouyère (1)

(1)Université de Liege, Département ArGEnCO, Geo3-Hydrogéologie et Géologie de l’Environnement,Liège, Belgium(2) Zuckerberg Institute for Water Research, Ben-Gurion University of the Negev, Israel(3) Faculté d’ingénierie biologique, agronomique et environnementale, Université catholique de Louvain,Louvain-la-Neuve, Belgium


Abstract (Oral)In order to improve risk characterization and remediation measures for soil and groundwater con-tamination, there is a need to improve in situ vadose zone characterization. However, most avail-able technologies have been developed in the context of agricultural soils. Such methodologiesare not applicable at industrial sites, where soils and contamination differ in origin and composi-tion. In addition, most technologies are applicable only in the first meters of soils, leaving deepervadose zones with lack of information, in particular on field scale heterogeneity. In order to over-come such difficulties, a vadose zone experiment has been setup at a former industrial site inBelgium. Industrial activities carried out on site left a legacy of soil and groundwater contamina-tion in BTEX, PAH, cyanide and heavy metals. The experiment comprises the combination of twotechniques: the Vadose Zone Monitoring System (VMS) and cross-hole geophysics. The VMSallows continuous measurements of water content and temperature at different depths of the va-dose zone. In addition, it provides the possibility of pore water sampling at different depths. Thesystem is formed by a flexible sleeve containing monitoring units along its depth which is installedin a slanted borehole. The flexible sleeve contains three types of monitoring units in the vadosezone: Time Domain Transmissometry (TDT), which allows water content measurements; VadoseSampling Ports (VSP), used for collecting water samples coming from the matrix; the FractureSamplers (FS), which are used for retrieving water samples from the fractures. Cross-hole geo-physics techniques consist in the injection of an electrical current using electrodes installed invertical boreholes. From measured potential differences, detailed spatial patterns about electri-cal properties of the subsurface can be inferred. Such spatial patterns are related with subsurfaceheterogeneities, water content and solute concentrations. Two VMS were installed in two slantedboreholes on site, together with four vertical boreholes containing electrodes for geophysical mea-surements. Currently the site is being monitored under natural recharge conditions. Initial resultsshow the reaction of the vadose zone to rainfall events, as well as chemical evolution of soil waterwith depth.


Transmissive and capacitive behavior of the unsaturated zone in Devo-nian limestones of the Calestienne (Belgium) and implications for thefunctioning of the epikarstic aquifer.

Amaël Poulain (1), Gaëtan Rochez (1), Vincent Hallet (1)

(1) Université de Namur, Département de Géologie, Namur, Belgium


Abstract (Poster)The shallow part of the bedrock is usually referred as the epikarstic area. This zone present aincreased degree of weathering and fracturation and therefore exhibit higher porosity and perme-ability compared with the "fresh" underlying lithologies. Due to this, it may contain a certainamount of water, close to saturation, and then constituting a "perched epikarstic aquifer" whithinthe unsaturated zone. Limestone aquifers represent the majority of global groundwater reserves.Their vulnerability is important, therefore the protection of this ressource is a major issue for thepreservation of the water reserves. The unsaturated zone (including epikarst), which is located be-tween the ground surface and the saturated zone (the aquifer sensu-stricto), represents a significanttransfer path for the aquifer recharge. Transportation and storage capacity features of the unsat-urated zone are poorly understood, mainly due to the lack of direct observational data. One wayto study the behavior of these areas, and particularely the role the epikarstic aquifer, is to recordflows into the open karst of the unsaturated zone. In order to do this, we measure the outflow ofspeleothem drip within caves. Since 2008, three stalactitic drips have been recorded within theHan-sur-Lesse karstic network. The experimental system consists of a self-siphoning reservoircollecting the drips and a pressiometric probe into the reservoir to estimate the dripping rate. Theflow has been estimated on a daily basis for more than 6 years (2008-2014, ongoing) and showsinteresting characteristics and frequent inter-annual correlations. The objective of this study is anattempt to connect the fluctuations of the input signal (daily rainfall and particularly infiltration)to the measured outflow fluctuations in the caves via a transfer function which may be linked toa conceptual model for the unsaturated zone. Several studies established that the flow rate in theunsaturated zone is a fonction of many parameters such as the soil and vegetation behavior, thesaturation state of the system during the infiltration process, the capacitive behavior of the epikarstaquifer, the bedrock fracturation and its implication on the existence of high-transmissivity path-ways through the unsaturated zone, atmospheric pressure, etc. The behavior of the unsaturatedzone also appear to be highly variable, even locally, probably due to the high spatial variability ofthe pre-mentionned parameters. We hope to present our first interpretations as soon as possibleas well as the developement of the first models based on the 2008-2013 dataset. This work willbe a part of a FNRS project in hydrogeology and geophysics (2013-2017). This project (KarstAquifer Research by Geophysics) involves two PhD thesis (UNamur and UMons) and will focuson the epikarstic dynamic via geophysical experimentation coupled with hydrogeological data ofthe saturated and unsaturated part of the karstic aquifer.


Developping an optimal soil and water quality monitoring network forthe Triffa irrigated perimeter (Eastern of Morocco)

K. ANDICH(1), M. VANCLOOSTER (2), B. SOUDI (3), M. JAVAUX (2) and M. SBAA (4)

(1) Centre régional de la recherche agronomique, Oujda, Morocco,(2) Université catholique de Louvain, Earth and life institute, Louvain-la-Neuve, Belgium,(3) Institut agronomique et vétérinaire Hassan II, Rabat, Morocco,(4) Centre oriental des sciences et technologies, UMP, Oujda, Morocco.


Abstract (Poster)In Morocco, the irrigated areas play a key role as real centers for agricultural and rural develop-ment, both at local and regional level. Thus, the irrigated agriculture contributes to about 45% onaverage of the agricultural value added. However, it is noted that the water and soil of differentirrigated areas are excessively exploited and threatened by different degradation problems. In thisstudy, we aim to design an advanced methodology allowing to monitor soil and water quality inthe irrigated perimeter of Triffa. The study area is the most fertile and productive agriculturalregion of north-east Morocco.The surface area of the plain rises to 61 000 ha of which 36 060 haare irrigated. The climate is warm semi-arid. The mean annual rainfall in 28 years is 331 mm.The mean annual temperature is 17.2 ◦C. Recognized by the quality of its clementine, the Triffaplain experienced during the last decade a large and rapid expansion of irrigated areas mainlycitrus through improved irrigation. Recent studies have shown that in this region, soil and waterresources are under pressure due to salinization and groundwater nitrate pollution. The degrada-tion of soil and water resources is largely caused by the increased use of agrochemicals, such asnitrogen fertilizers and pesticides, and the lack of control of irrigation and drainage of the plots.The protection and the preservation of these resources are top priority necessities, particularly inarid zones. We first aim to identify robust indicators of soil and groundwater degradation. Theseindicators should be able to measure the different functions and services provided by the soil andwater system. Subsequently, we will design a spatial network allowing to evaluate the state ofthe soil and water resource. We will use geostatistical and GIS tools to optimize the monitoringnetwork. This study is undertaken within the framework of a CUD-PIC project, aiming to developtools for the management of water and soils resources in the irrigated perimeter of Morocco.


Changes in soil properties after implementation of soil and water con-servation measures

Pablo Borja (1, 2), Veerle Vanacker (2), Gerard Govers (3)

(1) Proyecto CUD - Bélgica, Facultad de Ciencias Agropecuarias, Universidad de Cuenca, Ecuador,(2) University of Louvain, Earth and Life Institute, Georges Lemaître Centre for Earth and Climate Re-search, Belgium,(3) Physical Geography Research Group, KU Leuven, Belgium


Abstract (Poster)The aim of this study was to evaluate the effect of soil and water conservation schemes on thephysical and chemical (C, N and pH) properties of soils and sediments in degraded catchments.Other aspects that may affect soil dynamics, such as slope morphology, land use and vegetationdensity, were equally taken into account. Soil and sediment samples were taken in sites with differ-ent vegetation cover, land use and physiographic position. The following physical and chemicalparameters were measured: volumetric water content (θsat, θact), bulk density, pH, texture, or-ganic matter, C and N content). Five micro-catchments (0.2 up to 5 ha) were selected within a3 km2 area in the lower part of the Loreto catchment (Southern Ecuadorian Andes). The fivemicro-catchments differ in vegetation cover and implementation of soil and water conservationmeasures. The experimental design consisted of three micro-catchments: (1) DI with conserva-tion works, (2) DF with reforestation by Eucalyptus sp and (3) DT with no conservation works.Two micro-catchments have been monitored in an agricultural area: with (AI) and without (AT)bio-engineering works in the active gullies. The construction of checkdams in active gully floorsreduces water and sediment connectivity, and favors sediment accumulation behind small dams.The low bulk density and high porosity of the accumulated sediment leads to favorable conditionsfor root development. Pioneer species of plants from the Poaceae and Fabacea family can quicklydevelop in these setting. On the degraded hill slopes, soils are truncated and outcrops of weath-ered bedrock are frequent. Our first results do not show a clear relationship between volumetricwater content at saturation (θsat), bulk density, or C content. The saturation water content doesnot vary significantly between different sites, or land use types. Vegetation cover (%) appears toexert a strong control on the C content in the mineral soils. The highest C values are found in soilsof forest plantations of Eucalyptus and Pinus species. These plantations are located in areas thatwere previously affected by active gullying. Our results show that the establishment of a protectivevegetation cover is an important factor in soil restoration.

Section 2

Towards Sustainable Agroecosystems

The potential of reforesting landscapes to restore native floristic biodi-versity and enhance livelihoods in Ecaudor

Middendorp, R.S.

Georges Lemaître Center for Earth and Climate Research, University of Louvain, 3 Place Pasteur, B-1348Louvain-la-Neuve, Belgium


Abstract (No presentation)Although tropical deforestation continues, forest regrowth is taking place in several human-dominated landscapes. Reforestation in the form of secondary forest, planted forest, or agro-forestry becomes crucial for conservation due to the continuous expansion of agriculture. This re-search project responds to the current lack of knowledge on the restoration potential of reforestinglandscapes. A major challenge lies in finding ways to enhance biodiversity conservation withoutnegatively affecting local communities (Clough et al. 2011). Conservation dilemmas in human-dominated landscapes can be addressed by introducing market-based instruments, such as pay-ments for ecosystem services and eco-certification schemes. These instruments employ economicincentives that are intended to move farmers towards more sustainable land-uses. Farmer decisionson land-use affect the spatial configuration of habitat in the landscape but little research consideredthe consequences of landscape composition on conservation (Tscharntke et al. 2005). Assessingthe potential ecosystem-level impacts of these instruments is crucial for designing market-basedapproaches for biodiversity conservation that do not conflict with the livelihoods of local commu-nities (Wunder and Wertz-Kanounnikoff 2009; Blackman and Rivera 2010). Therefore, the mainobjective of this research project is to better understand the potential of reforesting landscapesto restore native floristic biodiversity and enhance livelihoods. It concentrates on two researchquestions: (i) How does the landscape-level pattern of reforestation affect the restoration potentialfor native floristic biodiversity in reforesting landscapes?; (ii) How can market-based instrumentsaffect the livelihood of farmers, whilst enhancing biodiversity at the landscape level? This projectfocuses both on reforesting landscapes and cacao agroforestry in Ecuador. To conclude, this re-search project will contribute to the knowledge on the restoration potential of reforesting land-scapes. The proposed methodology could be readily applied to answer similar questions in otherregions where other market-based instruments are in place and it provides important guidelinesfor policies that stimulate sustainable reforestation initiatives.

25


Carbon associated with clay and fine silt as an indicator for SOCdecadal evolution under different residue management practices.

Sylvain Trigalet (1), Kristof Van Oost (1), Christian Roisin (2), Bas van Wesemael (1)

(1) Université catholique de Louvain - Earth and Life Institute, Georges Lemaître Centre for Earth and Cli-mate Research,3, Place Louis Pasteur B-1348 Louvain-la-Neuve, Belgium(2) Walloon Agricultural Research Centre, Rue de Liroux, 9, B-5030 Gembloux, Belgium


Abstract (Oral)In the context of global changes and food security, it is essential to maintain or improve soil or-ganic carbon stocks in agroecosystems. The evolution of these stocks needs to be investigated indetails over decades to assess the sustainability of agricultural practices. Nevertheless, estimatesof soil organic carbon (SOC) sequestration or loss can be biased by large uncertainties due to tem-poral and spatial variability of organic carbon concentrations, even at the field scale. In order toreduce these uncertainties, we used the organic carbon associated with clay and fine silt particles(fine fraction) rather than SOC in bulk soil for assessing decadal changes. This approach limitsthe impact of the inherent variability of labile carbon (carbon non-associated with clay and finesilt) on SOC estimates. We analysed archived soil samples taken in 1970 and recent ones taken in2012 from an on-going long-term experiment in the Hesbaye region in Belgium. The experimentstarted in 1959 and contains three contrasting management practices (3 x 6 replicates): ResidueExport (RE), Farmyard Manure (FYM) and Residue Restitution (RR). After 42 years, there areno significant differences in bulk soil organic carbon concentrations between treatments (RE=9.2gC.kg-1 soil; FYM=10.4 gC.kg-1soil; RR=10.1 gC.kg-1soil). In contrast, there are significantdifferences (p<0.05) in stable carbon concentration between treatments over the same time period(RE=12.6 gC.kg-1 clay and fine silt; FYM=15.8 gC.kg-1 clay and fine silt; RR=14.7 gC.kg-1 clayand fine silt). Moreover, we can be 99% confident that stable carbon in the fine fraction increasedbetween 1970 and 2012 in FYM (+19%) and RR plots (+14%). There was no significant changeof stable carbon in RE plots over the same period. In 1970, no differences in stable carbon con-centration were detected between residue treatments. Labile carbon did not change significantlyfrom 1970 to 2012 but its variability increased for all plots except for the RE treatment. We usedthe Rothamsted Carbon model (RothC-26.3) to describe SOC stock changes under the differentresidue treatments. For bulk soil, observed trends in FYM and RR SOC stocks are in line withthe ones predicted. Modelled SOC stocks changes from 1962 to 2012 are -14% (RE) and +10%(FYM). We also used RothC-26.3 to understand the evolution of the sensitive and slow fractionsover time. On the one hand, we found that RothC was not capable to simulate the range of ob-served SOC stocks inter-annual variability. On the other hand, the increase of the RothC pool withslow decomposition (HUM) was similar to the trend in the carbon associated with the fine fractionobserved in the FYM and RR plots. This finding highlights that residue management can improvecarbon sequestration in agricultural soils, even if no changes are detected in bulk soil C.

2. Towards Sustainable Agroecosystems 27

Chemical Hydrolysis of Fagus sylvatica Wood: Dilute Acid vs. Alka-line Treatment

Krystian Miazek (1), Dorothee Goffin (2), Aurore Richel (3)

(1) University of Liege-Gembloux Agro-Bio Tech, AgricultureisLife Platform, Gembloux, Belgium(2)University of Liege-Gembloux Agro-Bio Tech, Cellule Innovation et Créativité, Gembloux, Belgium(3)University of Liège-Gembloux Agro-Bio Tech, Unit of Biological and Industrial Chemistry, Gembloux,Belgium


Abstract (Poster)Lignocellulosic biomass, found in a large variety of plants such as coniferous trees (Softwood),broad leaved trees (Hardwood), grasses and agricultural or food residues, is the most abundantsource of molecules required for production of biofuels and high value - added products. Lig-nocellulose is composed of three polymers: cellulose, hemicellulose and lignin. Cellulose is anon-branched polymer consisting of glucoses (hexoses). Hemicellulose is a complex carbohydratecontaining pentoses (mainly xyloses in the case of Hardwood, grasses and agricultural wastes) orhexoses (usually mannoses in the case of Softwood) as the main sugars. Lignin is a biopoly-mer with aromatic alcohols as basic monomeric units. Cellulose chains are arranged in bundlesand interlinked with hemicellulose. Lignin is cross-linked with hemicellulose and occupies spacebetween cellulose bundles. Due to complex polymeric structure, lignocellulosic materials are re-sistant to hydrolysis. A number of treatment methods (mechanical, chemical, biochemical) isimplemented to successfully hydrolyse lignocellulose. Amongst chemical methods harnessed tobreak lignocellulose structure, dilute acid and alkaline treatments are commonly mentioned, asthe most efficient ones. The objective of this study was to evaluate the effect of dilute acid andalkaline treatment on hydrolysis rate of polymeric components in Fagus sylvatica wood. Fagussylvatica also known as common beech is a broad leaved, deciduous tree that belongs to the fam-ily of Fagaceae, widely spread in Europe. Beech wood was determined to contain 48 % glucose,18 % xylose and 20 % Klason lignin in its dry material. Results of this study showed that 1 h hy-drolysis at 100 rC with the use of 3% H2SO4 resulted in 71 % removal of xylose and 4 % removalof glucose with Klason lignin remained intact. Additionally, the presence of sugar degradationproducts: 2 - furfural and hydroxymethylfurfural was detected in dilute acid hydrolysate. Releaseof 2 - furfural and hydroxymethylfurfural from beech wood was determined as 0.03 % and 0.1%, respectively. On the other hand, 1 h hydrolysis at 100 rC with the use of 7% NaOH caused59 % xylose removal and 11 % removal of Klason lignin with no effect on glucose. Dilute acidhydrolysis proved to be more efficient in removing xylose, but alkaline hydrolysis additionallyshowed to remove Klason lignin.


Autonomous robots: a potential weapon for farmers in their battleagainst weeds?

Sruthi Moorthy (1), Benoit Mercatoris (1), Bernard Boigelot (2)

(1) Gembloux Agro-Bio Tech , University of Liège , Belgium(2) Institut Montefiore, University of Liège, Belgium


Abstract (Oral)Autonomous robotic weed destruction can play a significant role in crop production as it is aimedat automating one of the few unmechanized and drudging tasks of agriculture i.e., manual weeddestruction. Robotic technology can also contribute to long-term sustainability with both eco-nomic and environmental benefits, by minimising the current dependency on chemicals. The aimof this study is to design a small low-cost versatile robot allowing the destruction of weeds that liebetween the crop rows by navigating in the field autonomously and using a minimum of a prioriinformation. For the robot to navigate autonomously, necessary and sufficient information can besupplied by a computer vision system. One important issue with the machine vision is to develop asystem that recognises the crop rows accurately and robustly and that is tolerant to problems suchas crops at varying growth stages, poor illumination conditions, missing crops, presence of weeds,etc. Aiming at accurate and robust real-time guidance of autonomous robot through the field, theplethora of image processing algorithms like Ostu’s threshold method and Hough transform willbe explored for two main processes, namely the image segmentation and crop row detection re-spectively. In order to overcome the issue of large variabilities encountered in agriculture, such aschanging weather conditions, intelligent stochastic data fusion and machine learning algorithmswill be used in order to combine data from heterogeneous sensors. Besides crop row detection,other major challenges that are foreseen include: mapping the unknown geometry of the field,high-level planning of efficient and complete coverage of the field, controlling the low-level oper-ations of the robot, and ensuring security. Specialised sensors such as GPS will be considered tohelp generating the map of the field enabling Simultaneous Localisation And Mapping (SLAM)in real time on a mobile platform. The generated map will be exploited along with the senso-rial information from crop row detection to efficiently plan and execute the guidance of the robotautonomously in the field, thereby enabling weed elimination.


Development of formulated elicitors to control bioagressors of wheat:how?

Geraldine LE MIRE (1), Magali DELEU (2), Marc ONGENA (3), Marie-Laure FAUCONNIER(4), Haissam JIJAKLI (5)

(1) Université de Liège - Gembloux Agro-BioTech, Phytopathology unit, Gembloux BELGIUM(2) Université de Liège - Gembloux Agro-BioTech, Department of Industrial and Biological Chemistry,Gembloux BELGIUM(3) Université de Liège - Gembloux Agro-BioTech, Bio-industries Unit, Gembloux BELGIUM(4) Université de Liège - Gembloux Agro-BioTech, Department of General and Organic Chemistry, Gem-bloux BELGIUM(5) Université de Liège - Gembloux Agro-BioTech, Phytopathology unit, Gembloux BELGIUM


Abstract (Poster)Major advancements were made these past decades in disease management research to develop ef-ficient biological control methods. Elicitors are currently considered as one of the most promisingtools in agriculture for the induction of plant resistance to various diseases, thereby contributing tothe reduction of chemical inputs in agroecosystems. Although some elicitor products are alreadyavailable on the market, it appears that a variable efficiency in the field, along with an uneasystatus in the current legislation and agricultural strategies, make this new biocontrol agent difficultto use. Besides these limitations, few elicitor treatments have yet been efficiently and specificallydesigned to protect crop plants such as wheat, which is grown and consumed worldwide, againstmajor diseases threatening both their yield and quality. In that context, a research is currentlycarried out in Gembloux Agro Bio-Tech (Agriculture is life platform) to develop a method basedon eliciting agents, tested in greenhouse and field conditions, to protect winter wheat against ma-jor diseases, namely Septoria tritici, Fusarium graminearum and Fusarium culmorum. This projectfocuses on (1) the screening of a large number of elicitors from different origins and structures, (2)the determination of the elicitation pathways of the most efficient molecules tested, (3) the studyof the influence of various factors on elicitation potential, (4) the determination of a formulationand a method of application to enhance the product efficacy, and (5) finally the confirmation oftheir practical efficacy under different systems of production. The advantages and methodology ofthis project will be described. The first tests carried out, previously to elicitor screening, consistin efficient infection of wheat plants with the chosen diseases. Developing a good protocol ofdisease symptom reproduction will indeed be necessary for the subsequent experiments. Futureresults should offer an interesting contribution to pest management strategies. Keywords: WinterWheat, Elicitors, Screening, Septoria tritici, Fusarium graminearum, Fusarium culmorum


Development of a hybrid LCA model for the wood construction sectorin Walloon region

Vanessa Zeller and Marc Degrez

Université libre de Bruxelles


Abstract (Oral)Together with the food and transport sector, the building sector is responsible for the highest en-vironmental impacts in the European Union (Tukker and Jansen 2006). Wood-based products andbuildings are often proposed as a means to reduce environmental impacts because they contributeless to abiotic resource depletion and they have the potential to store carbon temporary. Process-based life cycle assessment (LCA) is an appropriate tool to analyse environmental impacts ofproducts, but due to the fact that a variety of inputs are excluded, it deals with a systematic trunca-tion error that can lead to an underestimation of environmental impacts. Sector-based LCA modelsand input-output-based LCA show economic interactions of whole economies and can thereforeavoid the problem of system truncation. However, sector-based data often show high economicand geographical aggregation and the availability of environmental information at sector level islimited. Linking process-based and IO-based analysis is generally known as hybrid analysis. Thepurpose of this work is to develop a regional LCA model for the wood construction sector that con-siders complete system boundaries and broad environmental extensions. Through the improveddatabase and method, it will be possible to calculate environmental impacts such as global warm-ing potential and resource use at sector level more accurately. The results can help to identifystructural bottlenecks of the wood construction sector. Furthermore, it will be possible to comparethe sector outputs with other building products and to support priority setting in environmentalproduct policy. The proposed method is a hybrid LCA that requires the following implementationsteps: (1) collect primary data from representative wood building products and conduct process-LCA (2) create an environmentally extended input-output table and perform an input-output LCAand (3) create a hybrid model and conduct a hybrid LCA. The first results at sector level (2) showa global warming potential of approximately 169 t CO2-eq. per million EUR average wood prod-uct produced in Belgium in 2005. The majority of impacts are related to upstream emissions, forexample 27.9 % of greenhouse gases are caused by energy inputs, 14.8 % by transport operationsand 9.1 % by chemical products. Only 22.2 % of greenhouse gas emissions are related to the pro-duction step. Inputs which are most commonly excluded in process-LCA such as services accountfor 6.2 %. Comparing the global warming potential of wood products with products from othersectors shows that the wood building sector holds a middle position in the ranking of 60 productgroups (place 27). The methodology is further developed for more regionalized assessments.


Characterization of fatty acid and carotenoid production in an Acu-todesmus microalga isolated from the Algerian Sahara

Borhane Samir Grama (1, 2), Samira Chader (3), Douadi Khelifi (1),Ben Stenuit (2), Clayton Jeffryes (2, 4), and Spiros N. Agathos (2)

(1) Laboratory of Genetic Biochemistry and Plant Biotechnology, Faculty of Nature and Life Sciences,Université Constantine 1, Constantine, Algeria(2) Earth and Life Institute - Bioengineering Laboratory, Université catholique de Louvain, Place Croix duSud 2, bte. L07.05.19, B-1348 Louvain-la-Neuve, Belgium.(3) Algerian Center of Renewable Energy (Centre de Développement des Energies Renouvelables), Unitéde Recherche Appliquée en Energies Renouvelables (U.R.A.E.R.), Ghardaïa, Algeria(4) Research Fellow - Fonds de la Recherche - FNRS (Belgium).


Abstract (Poster)Microalgae are emerging as important cell factories for the production of various commercialproducts such as carotenoids and fatty acids (FA) and the potential still exists to convert algallipids into biofuels. Indeed, several species of microalgae have already demonstrated the capacityto accumulate intracellular concentrations of over 50% lipids on a dry cell weight (DCW) basisunder species-specific stresses such as nitrate or silicon limitation. An Acutodesmus microalgaof the Scenedesmaceae family isolated from the Algerian Sahara was characterized for its abil-ity to produce lipids, fatty acids (FA) and carotenoids under environmental stress conditions thatshould induce this production. Specifically, the combination of osmotic, nutritional and oxidativestress and the interactive effect of light intensity on lipid production and composition during batchgrowth were investigated. We also examined the recovery of the cell culture after the stress con-ditions were removed in order to study the feasibility of a reversible, and thus semi-continuous,cultivation process for the production of algal bioproducts. The FA produced by this strain isolatedfrom an environment typified by extreme heat showed a lower degree of unsaturation than thoseof other Scenedesmus which have been isolated from cold or temperate water environments, withno unsaturated C16 FA and more than 92% of the FA profile being comprised of FA with lessthan three unsaturated bonds. According to the degree of unsaturation and the cetane number, theFA profile from this strain is applicable to biofuel production. Under the highest lipid productionconditions, the fatty acid profile in the present study has a stationary phase degree of unsatura-tion (DU, 97 ± 2) and predicted cetane number (CN, 55 ± 2), two measures of biodiesel quality,comparable to or better than all readily available vegetable oil sources except for palm. Lipoge-nesis and carotenogenesis were easily reversible upon removal of the stress. We determined thatthe principal carotenoid produced by our isolate was canthaxanthin. The production of secondarycarotenoids was proportional to the lipid production suggesting that the primary role for secondarycarotenogenesis in our isolate is to prevent peroxidation of the lipids within OB. Our results rep-resent a step towards the development of strains suitable for biofuel production at the industrialscale.


Some Interesting Sources of Plant Seed Oil

Aman Paul (1), Sabine Danthine (1), Christophe Blecker (1), Stephanie Heuskin (2), GeorgesLognay (2) and Michel Frederich (3)

(1) Gembloux Agro-Bio Tech, Department of Food Science and Formulations, Gembloux, Belgium(2) Gembloux Agro-Bio Tech, Laboratory of Analytical Chemistry, Gembloux, Belgium(3) University of Liege, Department of Pharmacy, Liege, Belgium


Abstract (Poster)There is a growing realization worldwide that biodiversity is fundamental to agricultural produc-tion and food security, as well as a valuable ingredient of environmental conservation. Floweringstrips around the border of the crops serves as an important function to improve the biodiversity,besides this they play a major role in the ruminant nutrition and serve as a source of numer-ous beneficial compounds. It is well known that seeds store their food reserves for next gen-eration mainly in the form of lipids; some of the seeds from these flowering strips could be aninteresting source of lipids. These seed oils could play important role in food, pharmaceutical,cosmetics and other industries. The extraction of seed oil from four such plant species in Bel-gium namely Oregano (Origanum vulgare), Yellow Bedstraw (Galium verum), Common Self-heal(Prunella vulgaris) and Purple loosestrife (Lythrum salicaria) was carried out. Extraction wasdone by a cold extraction technique using chloroform/methanol in 2:1 ratio as solvent. Amountof oil extracted from Oregano, Yellow Bedstraw, Common Self-heal and Purple loosestrife was22.58±0.03 %, 3.28±0.01 %, 14.84±0.12 % and 20.32±0.15 %. The fatty acid profiles of thesefour species were determined by gas chromatography (using methyl esters of their fatty acids);Oleic acid and Linoleic acid were found in all the four species, Gamma-linolenic acid was foundin Purple loosestrife and Alpha-linolenic acid was found in Oregano and Common Self-heal plantspecies. Thermal behaviour of these four plant seed oils were analysed using Differential ScanningCalorimetry (DSC), while some other physicochemical properties of the seed oils were also ana-lyzed. These plant seed oils can be of great commercial importance. Keywords: Flowering Strips,Oil, Physicochemical Properties. For more info visit: www.agricultureislife.be Axis 4- Destinyand valorization of agriculture products Project B- Field border flowering strips as a source offood or non-food compounds

Section 3

Innovation in Environmental Engineering

Full-wave modeling of near-field ground-penetrating radar data forimaging root water uptake dynamics

Mourmeaux Nicolas, Meunier Félicien, Anh Phuong Tran, Lambot Sébastien

Université catholique de Louvain, Earth and Life Institute, Louvain-la-Neuve, Belgium


Abstract (Oral)Root water uptake dynamics at local scale can be studied in laboratory conditions by growingplants in rhizotron containing sand and by imaging the water content evolution of the mediumusing light transmission. This technique allows to accurately retrieve the water content with highresolution but cannot be applied in opaque medium as leaf-mold or clay, which is a major lim-itation for more realistic applications. Recently, ground-penetrating radar (GPR) has proven tobe one of the most promising techniques for high-resolution digital soil mapping at intermediatescale. Particularly, by using a full-wave inverse modeling of near-field GPR with a high frequencyantenna, the electrical properties of soil and their correlated water content with high spatiotempo-ral resolution can be reconstruct. In this study, we applied the approach by using an ultra-widebandfrequency-domain radar with a transmitting and receiving horn antenna operating in the frequencyrange 3-6 GHz for imaging, in near-field conditions, a rhizotron containing sand subject to dif-ferent water contents. Synthetic radar data were also generated to examine the well-posedness ofthe full-waveform inverse problem at high frequencies. Finally, we compared the water contentobtained by GPR and light transmission measurements. The results have shown that the near-fieldmodeled and measured GPR data perfectly match in the frequency and time domain for both dryand wet sand. In the case of dry sand, the estimated water content based on GPR and light trans-mission data was retrieved with small differences. Indeed, the thinness of the sand layer in therhizotron involves a biggest influence of the air in the GPR signal leading to an underestimatevalue of the water content. This research shows the potential of the GPR system and the near-fieldmodel to accurately estimate the water content of different soils with a high spatial resolution.Future studies will focus on the use of GPR to monitor root water uptake dynamics of plants inseveral soils systems.

33


Non-destructive sensing of tree trunk internal structures and woodproperties using microwave radar imaging and full-wave inversion

Laurence Mertens and Sébastien Lambot



Abstract (Oral)Forests cover about 30% of the Earth’s total land area and ensure essential functions such as pro-viding habitat to 80% of the world’s biodiversity, preventing soil erosion, sequestering carbonwithin its global cycle, and ensuring vital needs for populations who rely on trees to build houses,make furniture and paper, and produce energy. As a result of a growing population, increasingpressures and threats have been placed on forests, which have been largely depleted by loggingand conversion to agriculture. Detecting defects and deteriorations in trees and quantifying thequality of its wood for a particular application are therefore of paramount importance for opti-mal and sustainable forest management. Knowledge of eventual trunk deterioration also permitspreventing tree collapses and is thereby important to assure people’s security, such as, e.g., inpublic forests or populated areas. In sawmills, due to recent European laws forcing the producersto certify the quality of the construction wood, there are new needs for a quick and cheap wayto detects defects (especially knots) in wood logs and characterize wood mechanical properties.Some techniques already exist but are really expensive and not suited for practical applications.The main objective of my PhD research (project SENSWOOD, FRIA/FNRS) is to develop a novelmethodology for non-invasive imaging and characterization of standing tree trunks and logs prop-erties based on advanced microwave radar full-wave inverse modeling, thereby providing a rapidmonitoring way to detect hidden decays or defects and quantitatively estimate key wood physi-cal properties such as moisture, mechanical resistance or species-related dielectric signature (e.g.,for wood origin traceability). The originality of the project lies in the application and adaptationof a new near-field radar electromagnetic model using intrinsic transfer functions characterizingthe global reflection and transmission coefficients of the antenna, which has recently shown un-precedented efficiency and accuracy for determining soil and material properties. SENSWOODentails four major challenges: (1) to provide high-resolution and high-quality microwave radarimages of tree trunk sections, (2) to adapt the near-field electromagnetic model to tree structuresfor quantitative reconstructions to localize and quantify the extent of defects and deteriorations,(3) to derive new relationships between wood electromagnetic properties and physical propertiesof interest and (4), to validate the developed approaches for actual key cases. This will be realizedthrough numerical, controlled laboratory, and field experiments. SENSWOOD should result in anew operational method for non-destructive three trunk characterization, thereby allowing scien-tists to observe information that was not available before and providing the concerned actors witha new tool for improved forest management.

3. Innovation in Environmental Engineering 35

Wildflower strips, an alternative to pesticide? A tool for conservationbiological control: impact of functional diversity and mowing regime

Séverin Hatt(1), Roel Uyttenbroeck(1), Sarah Garre(1),Bernard Bodson(2), Arnaud Monty(3), Frédéric Francis(4)

(1) University of Liege, Gembloux Agro Bio-Tech, AgricultureIsLife, Gembloux, Belgium(2) University of Liege, Gembloux Agro Bio-Tech, Crop Science Unit and Experimental Farm, Gembloux,Belgium(3) University of Liege, Gembloux Agro Bio-Tech, Biodiversity and Landscape Unit, Gembloux, Belgium(4) University of Liege, Gembloux Agro Bio-Tech, Functional and Evolutionary Entomology Unit, Gem-bloux, Belgium


Abstract (Oral)Biological control methods are to be developed to ecologically limit pests on crops. Among them,ecological infrastructures such as wildflower strips are settled to attract natural enemies and par-asitoids. The diversity of insects present shall be able to interact and build up trophic relationsto finally limit pests on adjacent crops. Flower mixes, studied by researchers or settled by farm-ers, often present a high flower species diversity. However functional diversity, which means thediversity of flower traits, can be considered because these functional traits are those responsiblefor the attraction of insects. Moreover, wildflower strips are mown to conserve high vegetationdiversity as well as to harvest their biomass. But cutting destroys insect’s shelter and their foodresource. Thus it is a necessity to better know how mowing regime affects insect diversity andabundance and therefore their trophic relations. Experiments will take place at the experimen-tal farm of Gembloux Agro Bio-Tech (University of Liege). On a first one, 4 flower mixes withincreasing functional trait diversity (plus one control) will be settled in a 5 x 5 modalities Latinsquare. This will permit to study how functional trait diversity affects insect diversity, abundanceand their trophic relations. Insects will be trapped, identified and food webs will be built. On asecond experiment, 3 modalities of mowing will be applied on the 4 flower mixes and the control,this repeated 3 times. Insects will be observed on plants, identified and food webs will also bebuilt. These flower strips have been planted with perennial species in spring 2013. Species diver-sity and ground covering are dynamic processes that should be followed through time. Therefore,vegetation will be monitored 3 times a year with 1m x 1m quadrats. Our study has among otherobjectives to better adjust flower mixes for biological pest control. Therefore, crop yield and qual-ity will be measured to assess the efficiency of such a method to ecologically manage pests. ThisPhD work will be of 4 years and experiments will start in spring 2014.


Information content in frequency-dependent, multi-offset GPR datafor layered media reconstruction using full-wave inversion

Albéric De Coster (1), Anh Phuong (1) and Sébastien Lambot (1)

(1) Université catholique de Louvain, Environmental Sciences - Earth and Life Institute, Louvain-la-Neuve,Belgium


Abstract (Oral)Water lost through leaks can represent high percentages of the total production in water supplysystems and constitutes an important issue. Leak detection can be tackled with various techniquessuch as the ground-penetrating radar (GPR). Based on this technology, various procedures havebeen elaborated to characterize a leak and its evolution. In this study, we focus on a new full-waveradar modelling approach for near-field conditions, which takes into account the antenna effectsas well as the interactions between the antenna(s) and the medium through frequency-dependentglobal transmission and reflection coefficients. This approach is applied to layered media forwhich 3-D Green’s functions can be calculated. The model allows for a quantitative estimation ofthe properties of multilayered media by using full-wave inversion. This method, however, provesto be limited to provide users with an on-demand assessment as it is generally computationallydemanding and time consuming, depending on the medium configuration as well as the number ofunknown parameters to retrieve. In that respect, we propose two leads in order to enhance the pa-rameter retrieval step. The first one consists in analyzing the impact of the reduction of the numberof frequencies on the information content. For both numerical and laboratory experiments, this op-eration has been achieved by investigating the response surface topography of objective functionsarising from the comparison between measured and modelled data. The second one involves thenumerical implementation of multistatic antenna configurations with constant and variable offsetsin the model. These two kinds of analyses are then combined in numerical experiments. To per-form the numerical analyses, synthetic Green’s functions were simulated for different multilayeredmedium configurations. The results show that an antenna offset increase leads to an improvementin the response surface topography, which is more or less marked according to the initial infor-mation content. It also highlights the theoretical possibility of significantly reducing the numberof frequencies without degrading the information content. This last statement is confirmed withthe laboratory experiment which incorporates measurements done with a Vivaldi antenna abovea medium composed of one or more sand layers characterized by different water contents. As aconclusion, the offset and frequency analyses highlight the great potential of the model for im-proving the soil parameter retrieval while reducing the computation time for a given antenna(s) -medium configuration. Acknowledgments: This work benefited from networking activities car-ried out within the EU funded COST Action TU1208 "Civil Engineering Applications of GroundPenetrating Radar" and was supported by the Walloon Region through the "SENSPORT" project(Convention n◦1217720) undertook in the framework of the WBGreen research program.

List of participants

1. Jean-Baptiste Got, Université catholique de Louvain ([email protected])

2. Nicolas Feltz, Université catholique de Louvain ([email protected])

3. Ouedraogo Issoufou, Université catholique de Louvain ([email protected])

4. Nadia Sandra Kacem, Centre Wallon de Recherche Agronomique-Gembloux. ([email protected])

5. Anh Phuong Tran, Université catholique de Louvain ([email protected])

6. Arnaud Watlet, Université de Mons ([email protected])

7. Lorraine Dewaide, University of Namur ([email protected])

8. Nargish Parvin, ULg Gembloux Agro-Bio Tech ([email protected])

9. Thibaut Masy, ULg Gembloux Agro-Bio Tech ([email protected])

10. Sahar Abidi, National Agronomic Institute of Tunis ([email protected])

11. Olfa Hajji, National Agronomic Institute of Tunis ([email protected])

12. Louise Collier, Université de Namur ([email protected])

13. Félicien Meunier, Univeristé catholique de Louvain ([email protected])

14. Natalia Fernandez de Vera, Université de Liege ([email protected])

15. Amaël Poulain, Université de Namur ([email protected])

16. Karim Andich, Université catholique de Louvain ([email protected])

17. Pablo Borja, Université catholique de Louvain ([email protected])

18. Romaike Middendorp, Université catholique de Louvain ([email protected])

19. Sylvain Trigalet, Université catholique de Louvain ([email protected])

20. Krystian Miazek, ULg - Gembloux Agro-BioTech ([email protected])

21. Sruthi Moorthy Krishna Moorthy Parvathi, ULg - Gembloux Agro-BioTech ([email protected])

22. Geraldine Le Mire, ULg - Gembloux Agro-BioTech ([email protected])

23. Vanessa Zeller, Université libre de Bruxelles ([email protected])

24. Borhane Samir Grama, Université catholique de Louvain ([email protected])

37


25. Aman Paul, ULg - Gembloux Agro-BioTech ([email protected])

26. Nicolas Mourmeaux, Université catholique de Louvain ([email protected])

27. Laurence Mertens, Université catholique de Louvain ([email protected])

28. Séverin Hatt, ULg - Gembloux Agro-BioTech ([email protected])

29. Albéric De Coster, Université catholique de Louvai ([email protected])

envitam phd student day 2014 abstract book

Documents

soil properties

optimal soil

implementation of soil

soil piping

soil infrastructure

unsaturated zone

water uptake efficiency

water transfer processes