References of "Degre, Aurore"
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See detailCrop residue management in arable cropping systems under a temperate climate. Part 2: Soil physical properties and crop production. A review
Hiel, Marie-Pierre ULg; Chelin, Marie ULg; Parvin, Nargish ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (in press)

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See detailÉVOLUTION DE LA TENEUR EN EAU LE LONG D’UNE TOPOSEQUENCE FORESTIERE ARGILO-LIMONEUSE
Deraedt, Deborah ULg; Colinet, Gilles ULg; Degré, Aurore ULg

in Milieux Poreux et Transferts Hydriques (in press)

For the hydrological modeling of forested watersheds, the understanding of the forest hydrodynamic is essential. This study focusses on the hydrology of a Belgian forested plot with high stoniness and ... [more ▼]

For the hydrological modeling of forested watersheds, the understanding of the forest hydrodynamic is essential. This study focusses on the hydrology of a Belgian forested plot with high stoniness and steep slope. The soil water content is monitored at several positions on the toposequence and at different depth. During rain events, peak in soil water content are observed in different depth depending on the position along the toposequence. [less ▲]

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See detailEffect of different tillage systems on aggregate structure and inner distribution of organic carbon
Gao, Lili ULg; Beckers, Eléonore ULg; Liang, Guopeng et al

in Geoderma (2017), 288

Tillage is a common agricultural practice affecting soil structure and biogeochemistry. Pore network geometries are crucial to oxygen concentration, gas diffusivity, water location and water movement ... [more ▼]

Tillage is a common agricultural practice affecting soil structure and biogeochemistry. Pore network geometries are crucial to oxygen concentration, gas diffusivity, water location and water movement. Soil aggregates, 4–6 mm in diameter and collected from silty loam in Belgium and sandy loam in China, were scanned using a micro-computed tomography scanner. Images with a pixel size of 6.9 μm were then processed with ImageJ software for pore network analysis. The treatments were no tillage (C-NT) and conventional tillage (C-CT) in China, and shallow tillage (G-ST) and conventional tillage (G-CT) in Belgium. The results showed that aggregates in conservational tillage (G-ST and C-NT) had numerous connected pores compared with conventional tillage (G-CT and C-CT). The Euler number (Ev) was significantly lower and visible total porosity and surface area (SA) were significantly higher in conservational tillage (G-ST and C-NT) than in conventional tillage (G-CT and C-CT) in both studied locations. The predominant size of pores was significantly higher in conservational tillage (G-ST and C-NT) than in conventional tillage (G-CT and C-CT) (> 150 μm vs 90–120 μm). Pore location within the aggregates also showed differences, with porosity being evenly distributed in the aggregates under conventional tillage (G-CT and C-CT). Under conservational tillage (G-ST and C-NT), the aggregates were heterogeneous, showing higher porosity at the center of the aggregates. There was a higher soil organic carbon (SOC) content in the external layer than in the internal layer in conservational tillage in Belgium (G-ST). In no tillage in China (C-NT), the SOC in the external and internal layers, however, showed similar results. Overall, conventional tillage (G-CT and C-CT) reduced the proportion of the largest pores within soil aggregates, whereas there was no significant relationship between pore morphologies and SOC content. Further investigation is required to measure the active and slow carbon pool distribution in the different layers and under different tillage practices. [less ▲]

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See detailTraining engineers to meet the challenges of a changing world: how a competency framework improves teaching programs and team cohesion
Degré, Aurore ULg; Colaux, Catherine ULg

in Mazijn, Bernard (Ed.) 8th Conference on Education engineering for sustainable development (2016, September 05)

The competency framework is a complex and time-consuming exercise seen by most teachers as an administrative process. When applied, however, it can be a powerful tool for adapting curricula for engineers ... [more ▼]

The competency framework is a complex and time-consuming exercise seen by most teachers as an administrative process. When applied, however, it can be a powerful tool for adapting curricula for engineers to meet the emerging needs of society, including training in sustainable development. This paper looks at how to use the competency framework to generate a tool for bringing teachers together around shared objectives, helping students build their career paths and improving communication with the ‘outside world’. This approach, largely inspired by the Tardif approach, is being used for the Bioengineering Masters Degree in Environmental Sciences and Technology at the Gembloux Agro-Bio Tech Faculty, University of Liège, Belgium. The approach has allowed the teaching staff to build a common educational project aimed at enabling bioengineers to meet the needs of society [less ▲]

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See detailCharacterization of stony soils' hydraulic conductivity using laboratory and numerical experiments
Beckers, Eléonore ULg; Pichault, Mathieu; Pansak, Wanwisa et al

in SOIL (2016), 2

Determining soil hydraulic properties is of major concern in various fields of study. Although stony soils are widespread across the globe, most studies deal with gravel-free soils, so that the literature ... [more ▼]

Determining soil hydraulic properties is of major concern in various fields of study. Although stony soils are widespread across the globe, most studies deal with gravel-free soils, so that the literature describing the impact of stones on the hydraulic conductivity of a soil is still rather scarce. Most frequently, models characterizing the saturated hydraulic conductivity of stony soils assume that the only effect of rock fragments is to reduce the volume available for water flow, and therefore they predict a decrease in hydraulic conductivity with an increasing stoniness. The objective of this study is to assess the effect of rock fragments on the saturated and unsaturated hydraulic conductivity. This was done by means of laboratory experiments and numerical simulations involving different amounts and types of coarse fragments. We compared our results with values predicted by the aforementioned predictive models. Our study suggests that it might be ill-founded to consider that stones only reduce the volume available for water flow. We pointed out several factors of the saturated hydraulic conductivity of stony soils that are not considered by these models. On the one hand, the shape and the size of inclusions may substantially affect the hydraulic conductivity. On the other hand, laboratory experiments show that an increasing stone content can counteract and even overcome the effect of a reduced volume in some cases: we observed an increase in saturated hydraulic conductivity with volume of inclusions. These differences are mainly important near to saturation. However, comparison of results from predictive models and our experiments in unsaturated conditions shows that models and data agree on a decrease in hydraulic conductivity with stone content, even though the experimental conditions did not allow testing for stone contents higher than 20 %. [less ▲]

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See detailGiser: Gestion intégrée sol-érosion-ruissellement - Rapport d'activités 2015-2016
Bielders, Charles; Degré, Aurore ULg; Demarcin, Pierre ULg et al

Report (2016)

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See detailSoil-specific calibration of capacitance sensors considering clay content and bulk density
Parvin, Nargish ULg; Degré, Aurore ULg

in Australian Journal of Soil Research (2016)

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See detailContraintes Socio-économiques de Répartition des Terres et Impacts sur la Conservation des Sols dans les Hauts Plateaux de l’Ouest du Cameroun
Djoukeng, Henri Grisseur ULg; Dogot, Thomas ULg; Tankou, Christopher Mubeteneh et al

in Tropicultura (2016), 34(3), 231-241

This article combines the social survey data on access to land and those of the adoption of tied ridging as soil conservation technique to help better understand the management of erosion and runoff by ... [more ▼]

This article combines the social survey data on access to land and those of the adoption of tied ridging as soil conservation technique to help better understand the management of erosion and runoff by farmers in the Western Highlands of Cameroon, specifically in the hills of Fongo-Tongo villages’ group. The study focused on 230 plots owned by 157 respondents on 158 people inventoried. Five main modes of access to land were listed as: inheritance, purchase, temporary transfers, donations and rental. The owners and operators of the hills of gentle slopes (between11% and 17%) and steepest slopes (between 22% and 29%) were inventoried. Two main social ranks were identified: the dignitaries (Chiefs, Notables, Elites and heirs) and other (non-heirs son and women). The study showed that the agronomic abilities of plots as recognized by farmers are a key factor in the implementation of soil conservation techniques. The peasant approach of soil fertility has been scientifically proven by the physicochemical analysis of soil samples taken under plant species used locally as indicator of soil fertility (Pennisetum spp on fertile soils and Imperata cylindrica and Melinis minutiflora on poor soils). The study showed that access to land, adoption of tied ridging and slope exploitation were significantly influenced by the socio-economic status of farmers (p <0.05). [less ▲]

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See detailImproving Farmers’ Profitability, Soil and Water Conservation through an Adapted Tillage Technique: Experiences from the Cultivation of Potatoes in Bamiléké’s Hills, Cameroon
Djoukeng, Henri Grisseur ULg; Brostaux, Yves ULg; Tankou, Christopher Mubeteneh et al

in International Journal of Agriculture Innovations and Research (2016), 4(4), 708-716

On farms situated on slopes, such as those in the Western Highlands of Cameroon, the implementation of soil and water conservation techniques remains a major concern. The land preparation methods commonly ... [more ▼]

On farms situated on slopes, such as those in the Western Highlands of Cameroon, the implementation of soil and water conservation techniques remains a major concern. The land preparation methods commonly practiced in the Western Highlands agro-ecological zone of Cameroon are ridging along the steepest slopes (RASS) and the flatbed (FB). Field observations showed FB and RASS promote erosion by runoff, thereby compromising some agriculture functions (environmental function, production function and even social function). In order to ensure soil stability and maintain good water quality for rivers, a new land preparation method, tied ridging (TR), was tested. Erosion by runoff tests were conducted with four blocks of three plots on each of the most commonly exploited slopes, namely 11% and 29% gradient. With the main crop in the area (potato, Solanum tuberosum L.), the performance of RASS, FB, and TR were compared during crop years 2013 and 2014. The water runoff and sediments were collected per plot and per block after every rainfall. The results showed a significant difference between the FB or RASS and TR in terms of soil loss (Fmin(2, 2) = 322.7, p = 0.003), yields (F(2, 2) = 287.7, p = 0.003), and runoff water (Fmin(2, 12) = 2.4x106, p < 0.001). The TR technique generated a 7% increase in seedlings density, a 41% increase in the workforce, and an 81% and 100% increase in yields compared to FB in 11% and 29% slopes, respectively. The TR increased farmer’s profitability by 686 US$.ha-1 and 1420 US$.ha-1 over RASS in 11% and 29% slopes, respectively. The TR showed undeniable advantages: for the producer, the stress of additional work was offset by the gain in yields while creating additional job opportunities and improving the conservation of soil and water. Although the technique has several advantages, the provision of financial means for its implementation could be a negative point. Twelve farmers were involved in the experiment. The test results convinced the participants and other curious farmers who adopted the technology during the second experiment. [less ▲]

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See detailEvaluation of soil structural changes through macroscopic and microscopic measurement
Parvin, Nargish ULg; Degré, Aurore ULg; Chelin, Marie ULg et al

Poster (2015, April 16)

The heterogeneity of soil structure and pore size distribution are highly influenced by external factors like tillage systems and other agricultural management practices. However, changes in soil ... [more ▼]

The heterogeneity of soil structure and pore size distribution are highly influenced by external factors like tillage systems and other agricultural management practices. However, changes in soil hydrodynamic behavior are not fully understood and are still under research. Also, researchers have explained the impact of tillage practices on soil hydraulic properties related to pore size distribution, connectivity and orientation are involved but the characterization of these modifications and consequences remains a challenge. Furthermore, the relation between macroscopic measurements and microscopic investigation of the soil structure remains scarce. Recently, X-ray tomography (X- μCT) has been used in order to characterize changes in soil pore size distribution in various contexts and the method is able to link microtomography information to hydrodynamic measurement. In our study, X-μCT has been used in order to characterize changes in soil pore system. Since, tomography does not count most of the micropores, Richards’ pressure plate and evaporation method was also combined to get complete range of pore size distribution. We found good match between evaporation data with X-μCT at the macropore scale and evaporation data with pressure plate method at micropore scale. X-μCT data refines retention and hydraulic curves near saturation where Richards’ data alone can lead to numerous sets of fitted parameters. On the otherhand, evaporation data (Hyprop apparatus ©) provide comparable datasets with X-μCT. Combining micro and macroscopic measurements allows us to validate X-μCT information, which is otherwise not so obvious. [less ▲]

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See detailSoil porosity in agricultural context: A review of measurement techniques at various scales
Garré, Sarah ULg; Chelin, Marie ULg; Luong, Jeanne ULg et al

Poster (2015, April 13)

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there ... [more ▼]

Soil compaction was identified by European Commission as one of the eight main threats for agricultural soils. In order to address this issue, measurements of soil porosity are critical. However, there are as many techniques to measure as there are definitions of porosity. A single method is not sufficient to obtain a complete image of the soil porosity at various scales and encompassing different levels of complexity. Each existing method is characterized by a unique combination of a specific level of complexity, resolution and scale of measurement. In this review, we started by defining the basic terms linked to soil porosity in an agricultural context. Then we give an overview of relevant measurement techniques, from classical methods to recent advances. We present their advantages and disadvantages, the scales of measurement, the resolution, the expected accuracy and the susceptibility to errors. This work aims at guiding the choice for the best (combination of) technique(s) to answer questions related to agricultural soil porosity, categorizing techniques according to the parameters they focus on: from total porosity over pore size distribution, structure and connectivity up to the quantification of spatio-temporal dynamics. [less ▲]

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See detailGISER- Gestion intégrée Sol Erosion Ruissellement - rapport d'activités année 4
Demarcin, Pierre ULg; Dewez, Arnaud; Maugnard, Alexandre et al

Report (2015)

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See detailDétection de l'érosion dans un bassin versant agricole par comparaison d'images multidates acquises par drone
Lisein, Jonathan ULg; Pineux, Nathalie ULg; Pierrot-Deseilligny, marc et al

Scientific conference (2015, March 26)

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See detailSiltation and Pollution of Rivers in the Western Highlands of Cameroon: a Consequence of Farmland Erosion and Runoff
Djoukeng, Henri Grisseur ULg; Tankou, Christopher Mubeteneh; Degré, Aurore ULg

in International Journal of Agricultural Research and Reviews (2015), 3(3), 206-212

In the Western Highlands agro-ecological zone of Cameroon, rivers are constantly silted and polluted with eroded sediment and waste from cultivated land. This study characterizes and quantifies the amount ... [more ▼]

In the Western Highlands agro-ecological zone of Cameroon, rivers are constantly silted and polluted with eroded sediment and waste from cultivated land. This study characterizes and quantifies the amount of material coming from plots cultivated in the Méloh Watershed. In a natural rocky-bottomed well measuring 0.90 m deep, 3 m long, and 2.5 m wide, for a period of three years we performed the collection, differentiation, and measurement of trapped sediment in the cultivated part of river that runs through the watershed. Both cultivated sides of the watershed had fairly regular slopes of 14% on one side and 17% on the other side. The material retrieved consisted of soil, plant residues, chemical packages, and plastic casing used for irrigation. During the years 2012 and 2013, farmers practiced both flatbed cultivation and ridging along the steepest slopes. These two methods of land preparation are inefficient in terms of water conservation, as evidenced by the collection of 10.429 t.ha-1 average total sediment per year during this period. Tied ridging cultivation method was experimented during the 2013 crop year and adopted on 75% of plots in 2014. We subsequently collected 3.586 t.ha-1 total sediment, a decrease of 65.61% compared to the average of previous years. The tied ridging cultivation method significantly reduced siltation of the Méloh River (p<0.05). This study showed that traditional agricultural practices are a principal cause of siltation and pollution of the Méloh River. By extrapolation, we can state that the problem must occur in almost all rivers in the study area with similar topography and agricultural practices [less ▲]

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See detailGiser: formation à destination des communes
Dewez, Arnaud; Bielders, Charles; Degré, Aurore ULg et al

Learning material (2015)

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