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See detail1. Implantation des cultures
Eylenbosch, Damien ULg; Hiel, Marie-Pierre ULg; Meza Morales, Walter ULg et al

in Bodson, Bernard; Destain, Jean-Pierre (Eds.) Livre Blanc - Céréales (2014, September 11)

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See detailDiversity of Bacterial Communities in a Profile of a Winter Wheat Field: Known and Unknown Members
Stroobants, Aurore ULg; Degrune, Florine ULg; Olivier, Claire et al

in Microbial Ecology (2014)

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known ... [more ▼]

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known about the distribution and composition of bacterial communities through the soil profile, particularly in agricultural soils, as most studies have focused only on topsoils or forest and grassland soils. In the present work, we have used bar-coded pyrosequencing analysis of the V3 region of the 16S rRNA gene to analyze bacterial diversity in a profile (depths 10, 25, and 45 cm) of a well-characterized field of winter wheat. Taxonomic assignment was carried out with the Ribosomal Database Project (RDP) Classifier program with three bootstrap scores: a main run at 0.80, a confirmation run at 0.99, and a run at 0 to gain information on the unknown bacteria. Our results show that biomass and bacterial quantity and diversity decreased greatly with depth. Depth also had an impact, in terms of relative sequence abundance, on 81 % of the most represented taxonomic ranks, notably the ranks Proteobacteria, Bacteroidetes, Actinobacteridae, and Acidobacteria. Bacterial community composition differed more strongly between the topsoil (10 and 25 cm) and subsoil (45 cm) than between levels in the topsoil, mainly because of shifts in the carbon, nitrogen, and potassium contents. The subsoil also contained more unknown bacteria, 53.96 % on the average, than did the topsoil, with 42.06 % at 10 cm and 45.59 % at 25 cm. Most of these unknown bacteria seem to belong to Deltaproteobacteria, Actinobacteria, Rhizobiales, and Acidobacteria. [less ▲]

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See detailEffects of tillage practices and crop residue exportation on earthworm communities and soil physico-­chemical properties in silt loam arable soil (Belgium)
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

Poster (2014, June 08)

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological ... [more ▼]

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological properties of soil environments. Therefore, it is important to understand how earthworm communities are impacted by tillage systems and crop management practices. In the present study, earthworm and soil samples were collected from wheat cultivated fields in Gembloux, Belgium under the following four experimental treatments: (1) conventional tillage with crop residues left in the soil (CT/IN); (2) conventional tillage with crop residues removed from the field (CT/OUT); (3) reduced tillage with crop residues left in the soil (RT/IN); and (4) reduced tillage with crop residues removed from the field (RT/OUT). The different tillage systems were applied for four consecutive years prior to the initiation of the current study. Results indicated soil compaction was significantly higher in RT compared with CT up to a depth of 6–49 cm. Significant differences were not detected between residue incorporation depth systems, where results showed mean earthworm abundance was respectively 182.25 and 180 individuals.m-2 in CT and RT. Mean earthworm biomass was similarly not significantly different between CT and RT, where results were respectively 48.52 and 57.27 g.m-2. However, a significant difference was observed between IN and OUT treatments, suggesting the exportation of wheat residues will limit earthworm abundance and biomass in CT and RT plots. Data showed high representation of the endogeic earthworm ecological category, notably N. c. caliginosus regardless of treatment. Despite tillage system and exportation of crop residues, N. c. caliginosus, L. terrestris, and A. r. rosea exhibited high abundance, indicating tolerance to soil environmental conditions. For each depth, measures of soil physico-chemical properties showed significant differences among treatments. Furthermore, soil chemical property attributes were significantly higher in the first soil centimetres compared to lower soil layers. These results were attributable to earthworm activity and wheat residues, suggesting earthworms contributed to nutrient dynamics, particularly at increased soil depths. Overall, the results emphasise the influence of exportation of crop residues on earthworm community and also, the important influence of earthworm activity on soil physico-chemical properties change, processes which are closely linked. [less ▲]

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See detail2. Implantation des cultures
Eylenbosch, Damien ULg; Hiel, Marie-Pierre ULg; Meza Morales, Walter ULg et al

in Bodson, Bernard; Destain, Jean-Pierre (Eds.) Livre Blanc Céréales (2014, February 26)

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See detailImpact of agricultural practices on soil microbial communities in Belgium
Degrune, Florine ULg; Taminiau, Bernard ULg; Dufrêne, Marc ULg et al

Poster (2013, December 11)

The use of fertilizers in agricultural soils is becoming a real environmental issue (an obvious example is eutrophication caused by leaching of phosphorus and nitrates). Much research has focused on ... [more ▼]

The use of fertilizers in agricultural soils is becoming a real environmental issue (an obvious example is eutrophication caused by leaching of phosphorus and nitrates). Much research has focused on finding ways to reduce the use of chemicals, and investigating microbial life may lead to solutions. We know that bacteria and fungi are deeply involved in nutrient cycles. Recently the emergence of massive parallel sequencing has enabled us to realize that microbial diversity is huger than we expected. With such a tool it should be possible to study how soil management practices affect the microbial diversity of agricultural soils. A few such studies have been conducted, most of them focusing on bacteria. For Belgium in particular, there is a lack of data on this topic. Here the aim was to see how residue management and tillage practices affect communities of both bacteria and fungi in Belgian agricultural soils. For this we used 454 pyrosequencing of 16S bacterial and 28S fungal rRNA genes. Soil samples came from an experiment in which faba beans were grown with four soil management practices (tillage and no tillage, with and without crop residues), each repeated four times in a Latin square. Several chemical and physical characteristics were measured on each sample. The results show that fungi and bacteria are both impacted by Tillage practices. The main soil drivers are Magnesium and Phosphorus for Fungi communities, and Phosphorus and Potassium for bacteria communities. Finally, the fungi variance observed between plots is explained at 38% by Tillage, Magnesium and phosphorus. And the bacteria variance is explained at 28% by Tillage, Phosphorus and Potassium. [less ▲]

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See detail2. Implantation des cultures
Eylenbosch, Damien ULg; Pierreux, Jérome ULg; Dufranne, Delphine et al

in Bodson, Bernard; Destain, Jean-Pierre (Eds.) Livre Blanc - Céréales (2013, February 27)

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See detailImpact of the depth on bacterial diversity in an agricultural soil
Stroobants, Aurore ULg; Degrune, Florine ULg; Lambert, Christophe et al

Poster (2013, February 08)

Bacteria are the most abundant and diverse microorganisms in soils. They play an important role in soil formation, contribute to plant nutrition and are involved in various processes in agroecosystems ... [more ▼]

Bacteria are the most abundant and diverse microorganisms in soils. They play an important role in soil formation, contribute to plant nutrition and are involved in various processes in agroecosystems such as nutrient cycling. The aim of this study was to evaluate the impact of the depth on bacterial diversity and quantity in an agricultural soil. Samples was collected on May 2011 and May 2012 at three different depths : 10, 25 and 45 centimeters. The quantity of total bacteria was measured by real time PCR and the analysis of the diversity was performed by the high throughput sequencing technology. Results obtained by these methods show that the biomass and the bacterial quantity and diversity (Shannon index) decrease with the depth, particularly at 45 centimeters. The biomass is, in average, 6.5 fold less important at 45 cm than at 10 cm and the quantity is 17 fold lower at 45 cm than at 10 cm. Our results also indicate that many taxa, such as Betaprotebacteria, Deltaproterobacteria, Gammaproteobacteria, Acidobacteria and Burkholderiales are influenced by the depth. The results will be presented in more details on the poster. [less ▲]

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See detailIMPACT OF DEPTH AND SOIL COMPACTION ON BACTERIAL DIVERSITY IN SOIL
Stroobants, Aurore ULg; Degrune, Florine; Olivier, Claire et al

Poster (2012, August 19)

Bacteria are the most abundant and diverse microorganisms in soils. The amount of bacteria in soils can reach 10^10 cells per gram of soil. These organisms are involved in various processes in ... [more ▼]

Bacteria are the most abundant and diverse microorganisms in soils. The amount of bacteria in soils can reach 10^10 cells per gram of soil. These organisms are involved in various processes in agroecosystems such as nutrient cycling, contributing to plant nutrition, plant health and soil structure. The knowledge about this diversity is limited because only one percent of these organisms can be cultured by laboratory methods. During the last decades, many molecular-based techniques have been developed to assess the diversity of bacterial communities. The aim of this study was to determine the quantity and diversity of bacteria in two agricultural soils with differents soil management practices (tillage and no tillage) at different depths (10, 30 and 45 centimeters) and different compaction levels (high and low). Quantity was evaluated by real time PCR and diversity was analysed by the DGGE (Denaturing Gradient Gel Electrophoresis) technique. The results show that soil management has an impact on bacterial quantity at 45 centimeters and quantity is higher in till soil. Compaction level affects the bacterial quantity in till soil, quantity is higher in low compaction. And finally, depth influences the bacterial quantity in till and no till soil. In both soils, quantity decreases with the depth. The results will be presented and discussed on the poster. [less ▲]

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See detailLe cloisonnement des interbuttes en culture de pomme de terre : essai réalisé en collaboration avec Bayer CropScience (Huldenberg 2011)
Olivier, Claire; Goffart, Jean-Pierre; Baets, D. et al

in Brochure du Centre Pilote Pomme de terre - FIWAP (2011), 9.5

Detailed reference viewed: 37 (7 ULg)