References of "Roisin, Christian"
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See detailAn indicator for organic matter dynamics in temperate agricultural soils
Wesemael, Bas Van; Chartin, Caroline; Wiesmeier, Martin et al

in Agriculture, Ecosystems and Environment (2019), 274

The heterogeneity of soil organic matter (SOM) and the small changes in soil organic carbon (SOC) compared to large total SOC stocks hinder a robust estimation of SOC turnover, in particular for more ... [more ▼]

The heterogeneity of soil organic matter (SOM) and the small changes in soil organic carbon (SOC) compared to large total SOC stocks hinder a robust estimation of SOC turnover, in particular for more stable SOC. We developed a simple fractionation protocol for agricultural topsoils and tested it extensively on a range of soils in southern Belgium, including farmed soils, soils from long-term field trials, and paired sites after recent conversion to conservation farming. Our simple fractionation involves shaking the soil, wet sieving over 20 μm and analysing the SOC concentration in the soil as well as in the fine fraction (<20 μm). Eight biological indicators measured in an earlier study across the same monitoring network for the 0–10 cm topsoil were analysed in a conditional inference forest model in order to investigate the factors influencing the SOC fractions. Soil microbial biomass N explained the largest proportion of variation in both fractions. The fine fraction was also associated with factors explaining the regional trend in SOC distribution such as farmyard manure input, precipitation, land use and flow length. The variation in SOC content between treatments both in long-term trials and in farmers’ fields converted to conservation management was mainly attributed to changes within the coarse fraction. Thus, this fraction proves to be sensitive to management changes, although care should be taken to sample deep enough to represent the former plough layer inherited from the conventional tillage practice. Furthermore, the ratio between the coarse and the fine fraction showed a linear relationship (r² = 0.66) with the relative changes in SOC concentration over the last ten years. These fractions derived from a simple analytical approach are thus useful as an indicator for changes in SOC concentration. In analogy to biological indicators such as the soil microbial biomass C, the relationship between the fractions and relative changes in SOC concentration are likely to depend on climate conditions. Our methodology provides an indicator for use in routine analysis of agricultural topsoils, which is capable of predicting the effects of management practices on SOC concentrations in the short to mid-term (5–10 years). [less ▲]

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See detailImpact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils
Hiel, Marie-Pierre ULiege; Barbieux, Sophie; Pierreux, Jérome ULiege et al

in PeerJ (2018), 6(e4836),

Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important ... [more ▼]

Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (NO−3), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the NO−3 content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies. [less ▲]

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See detail1. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Bodson, Bernard; Watillon, Bernard (Eds.) Livre Blanc Céréales (2017, September 14)

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See detailCharacterisation of Luvisol compaction under two different tillage systems and field traffic zones by assessing soil mechanical properties
Taguem Ngoualadjio, Eric Martial ULiege; Destain, Marie-France ULiege; ROISIN, Christian et al

Conference (2017, June 20)

Compaction of arable soils is a consequence of tillage systems and agricultural machinery traffic year after year. Its negative effects on crop production and on the environment have been put into ... [more ▼]

Compaction of arable soils is a consequence of tillage systems and agricultural machinery traffic year after year. Its negative effects on crop production and on the environment have been put into evidence by several studies. However, soil compaction is a complex phenomenon and the understanding of the involved mechanisms related to agricultural practices still remains limited. This contribution aims to study the influence of the interaction between traffic intensity and tillage system on soil compaction. Soil samples were taken from topsoil (0.07-0.25 m), plough pan (0.30-0.35 m) and subsoil (0.35 – 0.52 m), on plots under long-term reduced tillage (RT) and conventional tillage (CT). For each tillage system, intensive traffic zones (IT) and non-intensive traffic zones (NT) were considered. Swelling index (Cs), compression index (Cc), precompression stress (Pc) obtained by oedometer test, porosity (n) and water content obtained by gravimetric determination were chosen to characterise the soil mechanical properties. An analysis of covariance (ANCOVA) was performed to study the effect of the depth, the tillage and the traffic intensity on the variables measured, with the water content as covariable. The results show that, after ten years of reconversion from CT to RT, the plough pan is still present in RT and its compaction appears as important as in CT ( nRT-30cm = 36.9% , nCT-30cm = 38.0%, p-value = 0.098). In subsoil, the compression index was high in CT, as well as in RT (CcRT = 0.150 kPa-1, CcCT = 0.148 kPa-1, p-value = 0.617), involving that this layer remains susceptible to compaction under heavy loads. Moreover, the mean value of the precompression stress (meanPc = 92±34 kPa) remains lower than stresses induced by heavy machines such as beet harvesters. The results also show that the presence of two traffic zones induces a spatial heterogeneity in the field (CcIT = 0.138 kPa-1; CcNT = 0.154 kPa-1, p-value = 0.031). These main results could be used in computational modelling to develop decision support systems to mitigate the effects of soil compaction. [less ▲]

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See detail2. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Bodson, Bernard; Watillon, Bernard (Eds.) Livre Blanc Céréales (2017, February 22)

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See detail10. 1. Impact de la gestion des résidus de cultures sur la fertilité des sols et la production agricole
Hiel, Marie-Pierre ULiege; Barbieux, Sophie ULiege; Pierreux, Jérome ULiege et al

in Bodson, Bernard; Watillon, Bernard (Eds.) Livre Blanc Céréales (2017, February 22)

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See detail1. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Bodson, Bernard; Watillon, Bernard (Eds.) Livre Blanc Céréales (2016, September 08)

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See detailSolindic: Etude de l'activité biologique du système "Sol-Plante" en vue de préserver les fonctionnalités des sols agricoles
Blondel, Alodie; Durenne, Bastien ULiege; Mingeot, Dominique et al

Report (2016)

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See detail10.1. L'intérêt de la culture en association de froment et de pois protéagineux d'hiver dans un objectif d'autonomie protéique
Pierreux, Jérome ULiege; Delaplace, Pierre ULiege; Roisin, Christian et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2016, February 24)

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See detail4. La fumure azotée
Meza Morales, Walter ULiege; Monfort, Bruno; Dumont, Benjamin ULiege et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2016, February 24)

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See detail2. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2016, February 24)

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See detailEffect of wheel traffic on the physical properties of a Luvisol
Destain, Marie-France ULiege; Roisin, Christian; Dalcq, Anne-Catherine ULiege et al

in Geoderma (2016), 262

The effects of machine traffic were assessed on a Luvisol in a temperate climate area in Belgium. Soil samples were taken from topsoil (0.07-0.25 m) and subsoil (0.35-0.50 m), on plots under long-term ... [more ▼]

The effects of machine traffic were assessed on a Luvisol in a temperate climate area in Belgium. Soil samples were taken from topsoil (0.07-0.25 m) and subsoil (0.35-0.50 m), on plots under long-term reduced tillage (RT) and conventional tillage (CT). Cone index (CI), bulk density (BD) and precompression stress (Pc) were chosen as indicators of mechanical strength. Mercury intrusion porosimetry was used to characterize the soil microporosity structure. It was presented in two forms: (i) cumulative pore volume vs. equivalent pore radius r, from which four classes of porosity were defined: r < 0.2 μm, 0.2 ≤ r < 9 µm, 9 ≤ r < 73 µm and r ≥ 73 μm; (ii) pore-size distribution (PSDs). In the reference situation where there had been no recent passage of machines, the voids with 0.2 ≤ r < 9 µm were the most important class in RT topsoil. The voids with r ≥ 73 µm represented the main porosity class in the topsoil of CT. In the subsoil, for both tillage systems, the porosity was almost equally distributed between voids with 0.2 ≤ r < 9 µm and voids with r greater than 9 µm. Machine traffic was carried out when the soil water content was close to the optimum Proctor. Although unfavourable, these wet conditions often occur during the beet harvesting period in Belgium. The highest modifications in soil structure (increase in BD and Pc, reduction of macroporosity r ≥ 73 μm) were observed in the topsoil of CT. More limited modifications were noticed in the soil structure of RT topsoil and subsoil layers but these latter are problematic in that the soil would no longer be loosened by subsequent tillage. These modifications could lead to soil consolidation as a result of wheel traffic year after year. [less ▲]

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See detailImpacts of wheel traffic on the physical properties of a Luvisol under reduced and conventional tillage
Saur, Marie-Laure ULiege; Destain, Marie-France ULiege; Roisin, Christian et al

Poster (2016)

Soil compaction is a complex mechanism which results in a decrease of soil porosity and an increase of soil strength. Such effects may reduce crop yield since they are harmful for root growth, germination ... [more ▼]

Soil compaction is a complex mechanism which results in a decrease of soil porosity and an increase of soil strength. Such effects may reduce crop yield since they are harmful for root growth, germination, mesofauna and bacterial life. Soil compaction may also reduce hydraulic conductivity which increases the risk of runoff, contamination of surface water, erosion and emission of greenhouse gases due to anaerobic processes. In the context of sustainable agriculture, it is crucial to characterise the impact of the agricultural techniques on the compaction state in the arable layer due to machine traffic. For this purpose, Soil samples were taken in a Luvisol at different depths, on plots under longterm reduced tillage (RT) and conventional tillage (CT). The impact of wheel traffic on the physical properties of the soils was also studied. The experimental approach consists in measuring traditional macroscopic soil properties such as bulk density and precompression stress, and combining them with pore size distribution obtained by mercury intrusion porosimetry. Automatic cone index measurements were initially performed to map the soil resistance and easily identify the sampling depths. The measurements revealed a plough pan at 30-cm depth under both CT and RT. Nevertheless, the subsoil under RT showed pieces of evidence of a natural regeneration process of the microporosity. The impact of wheel traffic was studied in RT and CT plots. It was shown that the passage of heavy machine such as beet harvester coupled to water content close to the optimum proctor is clearly unfavourable in terms of compaction. The measurements revealed large modifications of soil structure in the topsoil of CT, whereas the soil structure slightly changes through depth. However, the latter remains the more problematic case since the soil will not be loosened by tillage anymore, resulting in strongly compacted soil years after years. In addition to the experimental approach, numerical modelling was used in order to predict the soil compaction. A finite element method was used and the soil behaviour was modelled by an elastoplastic law (modified Cam-Clay model). The model parameters were calibrated from the experimental measurements. The simulations allowed to compare the porosity and the surface deformation after wheel traffic with the experiments. The variations of machine weight and tyre pressure were numerically studied and it was showed that the machine weight has an influence in the topsoil and the subsoil, whereas the tyre pressure affects only the topsoil. [less ▲]

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See detail2. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Bodson, Bernard; Watillon, Bernard (Eds.) Livre Blanc Céréales (2015, September 10)

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See detailComparison of soil porosity structure under conventional and reduced tillage
Destain, Marie-France ULiege; Roisin, Christian; Marmi, Abdeljalil ULiege et al

Conference (2015, July)

The soil porosity structures under conventional (CT) and reduced tillage (RT) were compared on a Luvisol (Belgium) on a field experiment initiated in 2003. The total porosity n was computed from the bulk ... [more ▼]

The soil porosity structures under conventional (CT) and reduced tillage (RT) were compared on a Luvisol (Belgium) on a field experiment initiated in 2003. The total porosity n was computed from the bulk density (BD) and the microporosity structure was analysed by mercury intrusion porosimetry (MIP) in the range 0.003 to 73μm. It was presented in two forms: (i) cumulative pore volume vs equivalent pore radius r, from which four classes of porosity were defined: r < 0.2μm (microporosity); 0.2 ≤ r < 9µm (mesoporosity); 9 ≤ r < 73µm (MIP macroporosity); r ≥ 73μm (macroporosity); (ii) pore-size distribution (PSD). Besides the MIP measurements, the intrinsic behaviour of soil samples was investigated in one-dimensional compression tests. At 0.10m depth, n was 7% lower under RT than CT and corresponded mainly to a reduction of macroporosity r ≥ 73 μm which corresponds to pores in which water movement is important (P<0.05). The plough pan structure under CT was clearly different from other layers. It presented a higher precompression stress (Pc>160kPa) related to an increased proportion of small voids. When converting CT to RT, this compacted layer was still persistent after 10 years at 0.30m depth. With BD reaching 1.7Mgm-3, this layer could restrict the gas/water fluxes with negative environmental consequences. In the subsoil, n was similar under CT and RT (44%) but the porosity structure of RT was more favourable than under CT. Indeed, the macroporosity r ≥ 73 μm was 10% higher under RT than CT and the radius of the more represented pores was increased (3.2μm in RT versus 2.7μm in CT). This suggested that process of recovering the textural porosity due to long-term climatic and biological processes had begun in the subsoil of RT. [less ▲]

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See detail2. Implantation des cultures
Eylenbosch, Damien ULiege; Meza Morales, Walter ULiege; Monfort, Bruno et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2015, February 25)

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

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

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See detailWhich P inputs are compatible with a sustainable agriculture at short and long-term?
Renneson, Malorie ULiege; Dufey, Joseph; Roisin, Christian et al

Poster (2014, August)

During the past 20 years, there has been a constant reduction in mineral fertilizer use due to price increases and environmental concerns. These changes can lead to a decrease in soil P content, which is ... [more ▼]

During the past 20 years, there has been a constant reduction in mineral fertilizer use due to price increases and environmental concerns. These changes can lead to a decrease in soil P content, which is already observed in some regions in Wallonia. Some new issues are now emerging. Is current cropping systems compatible with yield maintenance? Do organic fertilizers have a similar effect than mineral fertilizers? To answer to these questions, a short-term experiment in controlled conditions and 2 long-term experimental plots were studied. The short-term experiment permitted to study the kinetics of P after an input and differences between fertilizer types, whereas the long-term experiments studied 3 levels of P and K input and different organic compounds. Although an evolution of P content was observed, no difference of yield was found before about 20 years. However, after 47 years, available P levels were considered as low in zero P-input plots and attention must now be focused on these parcels. Zero P-input caused a mean yield decrease of 7%, while a double input increased yield by 2% in comparison to plots with input corresponding to crop export. Thus the zero P-input option is rarely economically profitable in the long-term and providing double the amount of P removed is never financially sustainable. Finally, no difference of P content was observed between organic and mineral fertilizers, except for manure which engendered a higher P content. In conclusion, organic and inorganic fertilizers had a relatively similar effect and overlooking P fertilizer is possible in the short-term but P content has to be followed at the long-term, although yield loss was limited. [less ▲]

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See detailDiversity of Bacterial Communities in a Profile of a Winter Wheat Field: Known and Unknown Members
Stroobants, Aurore ULiege; Degrune, Florine ULiege; 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 detailSoil compaction resulting from different soil tillage systems
Destain, Marie-France ULiege; Roisin, Christian; Mercatoris, Benoît ULiege

in ASABE - CSBE/ASABE Joint Meeting Presentation (2014, July)

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with ... [more ▼]

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with moldboard ploughing to 27 cm depth and (ii) reduced tillage (RT) with a spring tine cultivator to 10 cm depth. The measurements included bulk density (BD) and precompression stress (Pc) chosen as indicators of mechanical strength, and the pore size distribution (PSD) measured by mercury intrusion porosimetry (MIP). The tillage systems, the depth and their interaction had a significant effect on BD, Pc and PSD. In CT, in the topsoil, the soil strength was low and the total porosity n was about 50 %. In the subsoil, n decreased to 43 %. The PSD of CT was uni-modal in topsoil and subsoil in the MIP measurement range. The mean value of the mode rmax diminished from the topsoil toward the subsoil (from 2.5 microns to 1.9 microns). In RT, in the topsoil, the soil strength was higher than CT. BD did not vary much according to the depth. The total porosity n of RT was comprised between 40-45 % in the soil profile. The PSD was uni-modal and rmax increased from topsoil (around 2 microns) to subsoil (> 3 microns). This suggested the agglomeration of fine particles under the long-term action of mechanical loads, climatic agents, biological organisms or clay minerals acting as cementing agents. These phenomena could be at the origin of the increase of Pc with the depth without significant modification of BD. Such high values of Pc could be responsible of negative effects on root-growth leading to a more superficial root lateral development. [less ▲]

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