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See detailCan Electrical Resistivity Tomography offer us a dynamic view on what happens in the soil-plant continuum?
Garré, Sarah ULg

Conference (2014, December 05)

Root water and nutrient uptake and its relation to environmental factors is one of the least understood components in the terrestrial water balance and is of high importance for water resources management ... [more ▼]

Root water and nutrient uptake and its relation to environmental factors is one of the least understood components in the terrestrial water balance and is of high importance for water resources management, ecology and agriculture. As the processes in the soil-plant continuum are complex and inextricably intertwined, alternative, non-invasive measurement methods are necessary to unravel spatial and temporal dynamics of the system. Electrical resistivity tomography (ERT) has been proposed as a promising technique, since bulk resistivity maps and their temporal evolution may serve as a proxy for changes in soil moisture and pore water salinity, amongst others. However, the variables affecting the measured bulk electrical resistivity often change simultaneously in natural environments and not all influencing factors are yet well understood (e.g. influence of root biomass). Therefore, the method needs field-specific calibration. In addition to limitations due to signal-to-noise ratio and data inversion strategies, this implies that ERT still needs further development and research efforts for its use to characterize the soil-plant continuum. [less ▲]

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See detailIncorporate agroecology within research : The on-going story of four young researchers
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny ULg et al

in Broadening Scopes on Food, Squeezing Urban Hinterlands (2014, November 04)

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See detailSoil infrastructure evolution and its effect on water transfer processes under contrasted tillage systems - overview of methodologies with preliminary results
Parvin, Nargish ULg; Colinet, Gilles ULg; Garré, Sarah ULg et al

Conference (2014, June 10)

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect ... [more ▼]

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect of soil tillage along with residue management on the changing pattern of soil structure. This investigation will help to emphasize the different water flow dynamics especially the preferential flow processes through the soil that are influenced by the changes in structural distribution in the soil profile. The experimentation has been started from June 2013 in the research field in Gembloux. Soil profile description together with soil sampling has been carried out in the four objects of land management. 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 curves with pressure plate technique show significantly (p<0.05) higher water retention (Hwr) in WP than ST at 9.8 to 98 hPa, Hwr in WP than NI at 39 to 14710 hPa, Hwr in ST than NI at 294 to 14710 hPa and Hwr in WP than NO at 69 to 98 hPa. There was no significant difference in the water retention between NO and NI and ST and NO. Since, tillage practices generally increase soil porosity, the correlation between soil hydraulics and porosity distribution would expect to be different for different tillage systems. In our study, WP retains more water due to the increase of macroporosity than ST, NI and NO. As the changes in soil structure are usually noticed in the range of 9.8 to 98 hPa, so, we can conclude that there is certainly structural change between WP and 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 field under 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 experiments will be repeated twice a year. For the specific spatio-temporal comparison, the monitoring results from electrical resistance tomography will be available from the collaborated project of the same faculty. [less ▲]

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See detailIncrease in Soil Macroporosity managed with Winter Ploughing - a preliminary results
Parvin, Nargish ULg; Chelin, Marie ULg; Hiel, Marie-Pierre ULg et al

Poster (2014, February 07)

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the ... [more ▼]

Measurement of soil water retention capacity by the conventional pressure plate technique always gives a substantial view of soil porosity distribution. The structural orientation is observed in the beginning (higher water retention at 9.8 to 98 hPa water head pressure indicates greater proportion of macroporosity) of the soil moisture characteristic curve obtained from the water retention measurement. Since, tillage practices generally increase soil porosity, the correlation between soil hydraulics and porosity distribution would expect to be different for different tillage systems. In general, macroporosity increase with the adoption of conservative tillage or no tillage system but the changes can be varied with the seasonal variation. In our study, winter ploughing retains more water at the range of 9.8 to 98 hPa than Strip tillage, No-till residues in and No-till residues out. So, we can conclude that there is certainly increase in macroporosity in ploughing than other conservation practices of reduced tillage and no tillage. [less ▲]

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See detailAn Integrated Quantitative Method to Simultaneously Monitor Soil Erosion and Non-Point Source Pollution in an Intensive Agricultural Area
Ma, Li; Bu, Zhaozhong; Kerr, Philip et al

in Pedosphere (2014)

In China, some areas with intensive agricultural use are facing serious environmental problems caused by non-point source pollution (NPSP) as a consequence of soil erosion (SE). Until now, simultaneous ... [more ▼]

In China, some areas with intensive agricultural use are facing serious environmental problems caused by non-point source pollution (NPSP) as a consequence of soil erosion (SE). Until now, simultaneous monitoring of both NPSP and SE is difficult due to the intertwined effects of differences in crop type, topography and management in these areas. Based on meteorological data, a Geographic Information System (GIS) database and soil and water samples, we propose a new integrated method to monitor SE and NPSP simultaneously and apply to an intensive agricultural area (Nanjing area, ~6 000 km2) in eastern China. The results showed that the levels of soil total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (AN) and available phosphorus (AP) can be used to assess and predict the extent of NPSP and SE status in the study area. Most SE and the greatest NPSP loads occurred between April to August. The most seriously affected area in terms of SE and NPSP was the Jiangning District, implying that the effective management of SE and NPSP in this area should be considered a priority. The sub-regions with higher vegetation coverage contributed to less SE and NPSP, affirming the conclusions of previous studies, namely that vegetation is an effective factor in controlling SE and NPSP. This study shows that the application of our quantitative method has both high precision and reliability for the simultaneous monitoring of SE and NPSP occurring in intensive agricultural areas. [less ▲]

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See detailAssessing the influence of crop management strategies on the distribution of soil water content by ERT
Chelin, Marie ULg; Parvin, Nargish ULg; Hiel, Marie-Pierre ULg et al

Poster (2013, December 20)

Amongst other functions, cover crops are known to increase the stability of the soil structure. Commonly, their suppression is realized by using conventional tillage, but that it has been demonstrated to ... [more ▼]

Amongst other functions, cover crops are known to increase the stability of the soil structure. Commonly, their suppression is realized by using conventional tillage, but that it has been demonstrated to damage the soil structure, which directly impacts the soil water content. The proposed alternatives vary in terms of date, depth and type of tillage. As the soil water content is a major factor in agriculture, it is essential to better understand the influence of the cover crop management on its spatio-temporal distribution. Recent studies demonstrated the relevancy of the electrical resistivity tomography (ERT) to estimate the three-dimensional soil water content distribution. However, only a few of them were performed under field conditions. This study aims at (i) validating the use of the ERT method to estimate the soil water content distribution under field conditions (ii) quantifying the influence of cover crop management on the dynamic of soil water content along the growing season of a maize crop and on Belgian soil types. Three types of cover crop management content will be daily monitored: strip tillage, spring tillage and winter tillage. In order to assess the impact of plants on the soil water distribution, an additional plot will be burned after winter tillage. ERT will be used on a surface of 2 m² for each cover crop management. The validation of the average soil water content will be attended by using Time Domain Reflectrometers (TDR) and suction cups. The water stock obtained by ERT will be validated by using data from a weather station for the estimation of the evapotranspiration and rainfall and minirhizotrons for the assessment of the root water uptake. [less ▲]

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See detailSoil infrastructure evolution and its effect on water transfer processes under contrasted tillage systems with preliminary results of soil moisture sensor calibration
Parvin, Nargish ULg; Degré, Aurore ULg; Garré, Sarah ULg et al

Poster (2013, December 05)

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect ... [more ▼]

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect of soil tillage along with residue management on the changing pattern of soil structure. This investigation will help to emphasize the different water flow dynamics especially the preferential flow processes through the soil that are influenced by the changes in structural distribution in the soil profile. Mostly the preferential flow of water is addressed by the apparent velocity through the soil but this study will focus on soil structure along with soil moisture dynamics at aggregate scale or more specifically at pedon scale. The experimentation has been started from June 2013 in 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 organic matter restitution (NO)). Soil profile description has been carried out in the four objects of land management. Soil sampling has been done in different depths of soil according to the soil profile description. Soil samples will be used for the measurement of water retention capacity, hydraulic conductivity and x-ray microtomography. In addition, there will be soil moisture sensors (Decagon 10HS, 5TM and ML3 Thetaprobe) in the field under four different trials. The soils from the different trials and also from different depths (0-15, 25-30 and 50-60 cm) were calibrated with the sensors. The calibration results were significantly (p<0.05) different between Solcouvert and Solresidus and there was also significant (p<0.05) difference among depths of same field especially between 0-15 and 50-60 cm. Soil bulk density and textural differences are the main reason for the differences of moisture content of different sites and depths measured by the moisture probes. In addition, the results were inconsistent along with overestimation of moisture content if the manufacturer based equation is used for the calibration. In our study, to capture the total soil moisture networks, the moisture sensors will be in the field in winter to spring and summer to autumn. All the experiments will be repeated twice a year. For the specific spatio-temporal comparison, the monitoring results from electrical resistance tomography will be available from the collaborated project of the same faculty. [less ▲]

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See detailSoil infrastructure evolution and its effect on water transfer processes under contrasted tillage systems
Parvin, Nargish; Degré, Aurore ULg; Garré, Sarah ULg et al

Poster (2013, December 05)

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect ... [more ▼]

The heterogeneity of soil structure and porosity are highly influenced by external factors like tillage systems and other land management approaches. The aim of this project is to investigate the effect of soil tillage along with residue management on the changing pattern of soil structure. This investigation will help to emphasize the different water flow dynamics especially the preferential flow processes through the soil that are influenced by the changes in structural distribution in the soil profile. Mostly the preferential flow of water is addressed by the apparent velocity through the soil but this study will focus on soil structure along with soil moisture dynamics at aggregate scale or more specifically at pedon scale. The experimentation has been started from June 2013 in the research field known as Solcouvert (objects: strip-till versus winter ploughing) and Solresidus (objects: no-till with organic matter restitution versus no-till without organic matter restitution). Soil profile description has been carried out in the four objects of land management. Soil sampling has been done in different depths of soil according to the soil profile description. Soil samples will be used for the measurement of water retention capacity, hydraulic conductivity and x-ray microtomography. In addition there will be soil moisture sensors (Decagon 10HS, 5TM and ML3 Thetaprobe) in the field under four different trials. The soils from the different trials and also from different depths (0-15, 25-30 and 50-60 cm) were calibrated with the sensors. The calibration results were significantly (p<0.05) different between Solcouvert and Solresidus and there was also significant (p<0.05) difference among depths of same field especially between 0-15 and 50-60 cm. Soil bulk density and textural differences are the main reason for the differences of moisture content of different sites and depths measured by the moisture probes. In addition, the results were inconsistent along with overestimation of moisture content if the manufacturer based equation is used for the calibration. We conclude that, site and depth wise calibration of low cost sensors is very essential for the interpretation of results. In our study, to capture the total soil moisture networks, the moisture sensors will be in the field during the crop season. All the experiments will be repeated twice a year. For the specific spatio-temporal comparison, the monitoring results from electrical resistance tomography will be available from the collaborated project of the same faculty. [less ▲]

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See detailT-26. Exploring Root Uptake Under High Frequency Irrigation Using Electrical Resistivity Tomography
Garré, Sarah ULg; Furman, Alex; Assouline, Shmuel et al

Poster (2013, October 22)

Root uptake and its relation to environmental factors, and primarily soil water content, are perhaps the least understood component in terrestrial water balance and is of high importance for water ... [more ▼]

Root uptake and its relation to environmental factors, and primarily soil water content, are perhaps the least understood component in terrestrial water balance and is of high importance for water resources management, ecology and agriculture. In this research we explore the spatial and temporal distribution of soil water in high resolution using electrical resistivity tomography (ERT). Bell peppers were planted in a chamber and irrigated in two different schemes, differing only in irrigation frequency (daily and eight-daily irrigation, where the daily dose is equal for both treatments). This irrigation difference results in very different spatio-temporal distribution of the soil water in the root zone, which in turn derives spatio-temporal differences in root uptake. Experiment was conducted under a screen-house in Mediterranean summer conditions, i.e. very high evapotranspiration. Resistivity surveys, using 96 electrodes placed around the growth chamber and at soil surface (Figure 1) were taken over 10 times daily. Plants subjected to high frequency irrigation generally were faster in growth and matured about a week earlier. This is primarily attributed to the higher water content that exists in the root zone, and primarily during the climatically stressing noon hours. Inverted images (e.g. Figure 2) provide an interesting insight into the spatio-temporal distribution of the root uptake. This in turn can now be correlated to the spatial location of the roots, and to the soil induced water content dynamics. [less ▲]

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See detailÉlaboration du référentiel de compétences du master bioingénieur en Sciences et Technologies de l'Environnement
Colaux-Castillo-Bocanegra, Catherine ULg; Colinet, Gilles ULg; Debouche, Charles ULg et al

in Poulin, Richard (Ed.) Séminaire CITEF 2013 La liaison formation-emploi : l'approche compétences et la formation tout au long de la vie (2013, October 18)

Le département des Sciences et Technologies de l’Environnement (STE) de Gembloux Agro-Bio Tech faculté de l’Université de Liège a profité d’un changement d’intitulé de son diplôme de bioingénieur pour ... [more ▼]

Le département des Sciences et Technologies de l’Environnement (STE) de Gembloux Agro-Bio Tech faculté de l’Université de Liège a profité d’un changement d’intitulé de son diplôme de bioingénieur pour réviser son programme des études. Pour ce faire, il a adopté l’approche compétence. Afin de préparer au mieux ses futurs diplômés aux attentes du monde professionnel actuel et à venir, des anciens diplômés et des employeurs potentiels ont participé à la validation du référentiel de compétences associé à cette formation. Cette publication reprend les étapes clés de la création du référentiel de compétences et son exploitation dans la conception d’un programme des études cohérent. [less ▲]

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See detailLinking stable isotope methods and electrical resistivity tomography imaging: Improving our understanding of competition in poly - culture systems
Hussain, Khalid; Wongleecharoen, Chalemchart; Hilger, Thomas et al

Scientific conference (2013, September)

Poly-cultures are cropping systems using multiple crops in the same space and time, avoiding large stands of sole crops, hence contributing to reconciliation ecology. These land uses have several ... [more ▼]

Poly-cultures are cropping systems using multiple crops in the same space and time, avoiding large stands of sole crops, hence contributing to reconciliation ecology. These land uses have several advantages over monocultures, e.g. increased biodiversity and diversification of agricultural production. Coupled with soil conservation measures, they also contribute to erosion control and resource protection in fragile areas. The viability of such systems often depends on their efficiency under limited resource conditions, which in turn makes them acceptable among the farming community. Most farmers, however, are reluctant to adopt such systems because they may compete for water and nutrients. This study was conducted during 2011 on the Queen Sirikit research farm, Ban Bo Wi village, Ratchaburi province, in North-West Thailand to investigate the competition in maize based soil conservation systems. The soil at the field site ranged from an endoleptic Alisol to ahyper skelletic Leptosol. The treatments were maize under farmer's practice (control) and maize-chili intercropping combined with alley cropping of Leucaena under minimum tillage and Jack bean relay cropping with and without fertiliser application. Plot size was 4 m by 13 m and slope of 18-20%. We used both carbon isotopic discrimination and electrical resistivity tomography (ERT) imaging, a novel non-invasive method, to understand and distinguish the competition for water and nutrients in tropical field conditions. A negative relationship was observed between 13C isotopic discrimination and total nitrogen in grain with R2 ranging from 0.63 (p ≤ 0.01) to 0.70 (p ≤ 0.001) while a positive correlation was found between total nitrogen in grains and total dry matter production with R2 ranging from 0.51 (p ≤ 0.04) to 0.84 (p ≤ 0.001). Nutrient competition induced an increase in δ13C values in maize rows close to Leucaena hedgerows and decreased their total dry matter production. ERT imaging showed different water depletion patterns during the growing season, directly linked with the growth and development of maize such as leaf area index, plant height and canopy cover. This helped explaining the impact of hedgerows on crop growth and yields in maize rows adjacent to the hedges, leading to various spatial patterns along the slope. [less ▲]

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See detailCan we use electrical resistivity tomography to measure root zone competition in fields with multiple crops?
Garré, Sarah ULg; Coteur, Ine; Wongleecharoen, Chalemchart et al

in Procedia Environmental Sciences (2013, June 20)

Contour hedgerow intercropping systems have been proposed to reduce run-off and control soil erosion on steep agricultural land. However, competition for water and nutrients between crops and associated ... [more ▼]

Contour hedgerow intercropping systems have been proposed to reduce run-off and control soil erosion on steep agricultural land. However, competition for water and nutrients between crops and associated hedgerows may reduce the overall performance of these systems. ERT measurements conducted in Thailand showed that the soils of our experimental plots were very heterogeneous both along the slope as with depth. This observation highlighted some constraints of the ERT method for soil moisture monitoring in the field. Nevertheless, the data indeed revealed contrasting water depletion patterns under monocropping and intercropping systems, which could also be related to plant parameters. [less ▲]

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See detailNon-invasive monitoring of soil water dynamics in mixed cropping systems: A case-study in Ratchaburi province, Thailand
Garré, Sarah ULg; Coteur, Ine; Wongleecharoen, Chalemchart et al

in Vadose Zone Journal (2013)

Agriculture on shallow or steep soils in the humid tropics often leads to low resource use efficiency. Contour hedgerow intercropping systems have been proposed to reduce run-off and control soil erosion ... [more ▼]

Agriculture on shallow or steep soils in the humid tropics often leads to low resource use efficiency. Contour hedgerow intercropping systems have been proposed to reduce run-off and control soil erosion. However, competition for water and nutrients between crops and associated hedgerows may reduce the overall performance of contour hedgerow systems. Electrical resistivity tomography (ERT) is a valuable technique used to assess the distribution and dynamics of soil moisture noninvasively. In this study, we demonstrated its potential to measure soil water depletion in the field in distinct cropping patterns in Ratchaburi province, Thailand. The measurements showed that the soils of our experimental plots were very heterogeneous both along the slope as with depth. This observation highlighted some constraints of the ERT method for soil moisture monitoring in the field, such as the difficulty of defining a relationship between electrical conductivity and soil moisture in very heterogeneous soils. Nevertheless, spatial analysis of the data revealed contrasting water depletion patterns under monocropping and intercropping systems. In this way, ERT provides access to information about the vadose zone moisture dynamics that would be unavailable with classical soil moisture measurements. [less ▲]

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See detailEstimating the parameters of a 3-D root distribution function from root observations with the trench profile method: case study with simulated and field-observed root data
Vansteenkiste, Joachim; Van Loon, Jelle; Garré, Sarah ULg et al

in Plant and Soil (2013)

Background and Aims Root length density (RLD) is a parameter that is difficult to measure, but crucial to estimate water and nutrient uptake by plants. In this study a novel approach is presented to ... [more ▼]

Background and Aims Root length density (RLD) is a parameter that is difficult to measure, but crucial to estimate water and nutrient uptake by plants. In this study a novel approach is presented to characterize the 3-D root length distribution by supplementing data of the 3-D distribution of root intersections with data of root length density from a limited number of soil cores. Methods The method was evaluated in a virtual experiment using the RootTyp model and a field experiment with cauliflower (Brassica oleracea L. botrytis) and leek (Allium porrum, L.). Results The virtual experiment shows that total root length and root length distribution can be accurately estimated using the novel approach. Implementation of the method in a field experiment was successful for characterizing the growth of the root distribution with time both for cauliflower and leek. In contrast with the virtual experiment, total root length could not be estimated based upon root intersection measurements in the field. Conclusions The novel method of combining root intersection data with root length density data from core samples is a powerful tool to supply root water uptake models with root system information. [less ▲]

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See detailSoil apparent conductivity measurements for planning and analysis of agricultural experiments: A case study from Western-Thailand
Rudolph, Sebastian; Wongleecharoen, Chalemchart; Marchant, B. et al

E-print/Working paper (2013)

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See detailCan we use Electrical Resistivity Tomography to measure root zone moisture dynamics in fields with multiple crops?
Garré, Sarah ULg; Coteur, Ine; Wongleecharoen, Chalemchart et al

in 2012 Scientific program (2012, December 07)

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See detailNon-invasive monitoring of mixed cropping systems. A case-study in Ratchaburi province, Thailand
Garré, Sarah ULg; Coteur, Ine; Diels, Jan et al

Poster (2012, July)

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See detailEvaluating experimental design of ERT for soil moisture monitoring in contour hedgerow intercropping systems
Garré, Sarah ULg; Günther, Thomas; Diels, Jan et al

in Vadose Zone Journal (2012)

Detailed reference viewed: 32 (2 ULg)